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Hore DK. Phase of the second-order susceptibility in vibrational sum frequency generation spectroscopy: Origins, utility, and measurement techniques. J Chem Phys 2024; 161:060902. [PMID: 39132786 DOI: 10.1063/5.0220817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 07/17/2024] [Indexed: 08/13/2024] Open
Abstract
Vibrational sum frequency generation can provide valuable structural information at surfaces and buried interfaces. Relating the measured spectra to the complex-valued second-order susceptibility χ(2) is at the heart of the technique and a requisite step in nearly all subsequent analyses. The magnitude and phase of χ(2) as a function of frequency reveal important information about molecules and materials in regions where centrosymmetry is broken. In this tutorial-style perspective, the origins of the χ(2) phase are first described, followed by the utility of phase determination. Finally, some practical methods of phase extraction are discussed.
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Affiliation(s)
- Dennis K Hore
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada and Department of Computer Science, University of Victoria, Victoria, British Columbia V8W 3V6, Canada
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2
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Ma YH, Wang C, Yang J, Li B, Han X, Lu X. Disulfide-Driven Charge and Hydrophobicity Rearrangement of Remodeled Membrane Proteins toward Amyloid-Type Aggregation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:16145-16150. [PMID: 39054779 DOI: 10.1021/acs.langmuir.4c01201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
As a common pathological hallmark, protein aggregation into amyloids is a highly complicated phenomenon, attracting extensive research interest for elucidating its structural details and formation mechanisms. Membrane deposition and disulfide-driven protein misfolding play critical roles in amyloid-type aggregation, yet the underlying molecular process remains unclear. Here, we employed sum frequency generation (SFG) vibrational spectroscopy to comprehensively investigate the remodeling process of lysozyme, as the model protein, into amyloid-type aggregates at the cell membrane interface. It was discovered that disulfide reduction concurrently induced the transition of membrane-bound lysozyme from predominantly α-helical to antiparallel β-sheet structures, under a mode switch of membrane interaction from electrostatic to hydrophobic, and subsequent oligomeric aggregation. These findings shed light on the systematic understanding of dynamic molecular mechanisms underlying membrane-interactive amyloid oligomer formation.
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Affiliation(s)
- Yong-Hao Ma
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chu Wang
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jingjing Yang
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Bolin Li
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Xiaofeng Han
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xiaolin Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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3
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Dong K, Yang G, Wang M, Bian J, Zhu L, Zhang F, Yu S, Liu S, Xiao JD, Guo X, Jiang X. Impact of Dipole Effect on Perovskite Solar Cells. CHEMSUSCHEM 2024; 17:e202301497. [PMID: 38446050 DOI: 10.1002/cssc.202301497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/23/2024] [Indexed: 03/07/2024]
Abstract
Interface modification and bulk doping are two major strategies to improve the photovoltaic performance of perovskite solar cells (PSCs). Dipolar molecules are highly favored due to their unique dipolarity. This review discusses the basic concepts and characteristics of dipoles. In addition, the role of dipoles in PSCs and the corresponding conventional characterization methods for dipoles are introduced. Then, we systematically summarize the latest progress in achieving efficient and stable PSCs in dipole materials at several key interfaces. Finally, we look forward to the future application directions of dipole molecules in PSCs, aiming at providing deep insight and inspiration for developing efficient and stable PSCs.
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Affiliation(s)
- Kaiwen Dong
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Guangyue Yang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Minhuan Wang
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, China
| | - Jiming Bian
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, China
| | - Lina Zhu
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Fengshan Zhang
- Shandong Huatai Paper Co., LTD & Shandong Yellow Triangle Biotechnology Industry Research Institute Co., LTD, Dongying, 257335, China
| | - Shitao Yu
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Shiwei Liu
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Juan-Ding Xiao
- Institutes of Physical Science and Information Technology, Anhui Graphene Materials Research Center, Anhui University Hefei, Anhui, 230601, P. R. China
| | - Xin Guo
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian, 116023, China
| | - Xiaoqing Jiang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
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4
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Wu Y, Lin T, Santos E, Ahn D, Marson R, Sarker P, Chen X, Gubbels F, Shephard NE, Mohler C, Wei T, Kuo TC, Chen Z. Molecular behavior of silicone adhesive at buried polymer interface studied by molecular dynamics simulation and sum frequency generation vibrational spectroscopy. SOFT MATTER 2024; 20:4765-4775. [PMID: 38841820 DOI: 10.1039/d4sm00407h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Silicones have excellent material properties and are used extensively in many applications, ranging from adhesives and lubricants to electrical insulation. To ensure strong adhesion of silicone adhesives to a wide variety of substrates, silane-based adhesion promotors are typically blended into the silicone adhesive formulation. However, little is known at the molecular level about the true silane adhesion promotion mechanism, which limits the ability to develop even more effective adhesion promoters. To understand the adhesion promotion mechanism of silane molecules at the molecular level, this study has used sum frequency generation vibrational spectroscopy (SFG) to determine the behavior of (3-glycidoxypropyl)trimethoxy silane (γ-GPS) at the buried interface between poly(ethylene terephthalate) (PET) and a bulk silicone adhesive. To complement and extend the SFG results, atomistic molecular dynamics (MD) simulations were applied to investigate molecular behavior and interfacial interaction of γ-GPS at the silicone/PET interface. Free energy computations were used to study the γ-GPS interaction in the sample system and determine the γ-GPS interfacial segregation mechanism. Both experiments and simulations consistently show that γ-GPS molecules prefer to segregate at the interface between PET and PDMS. The methoxy groups on γ-GPS molecules orient toward the PDMS polymer phase. The consistent picture of interfacial structure emerging from both simulation and experiment provides enhanced insight on how γ-GPS behaves in the silicone - PET system and illustrates why γ-GPS could improve the adhesion of silicone adhesive, leading to further understanding of silicone adhesion mechanisms useful in the design of silicone adhesives with improved performance.
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Affiliation(s)
- Yuchen Wu
- Department of Chemistry, University of Michigan, MI 48109, USA.
- Department of Macromolecular Science and Engineering, University of Michigan, MI 48109, USA
| | - Ting Lin
- Department of Chemistry, University of Michigan, MI 48109, USA.
- Department of Macromolecular Science and Engineering, University of Michigan, MI 48109, USA
| | | | - Dongchan Ahn
- The Dow Chemical Company, Midland, MI 48674, USA
| | - Ryan Marson
- The Dow Chemical Company, Midland, MI 48674, USA
| | - Pranab Sarker
- Department of Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA.
- Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA
| | - Xiaoyun Chen
- The Dow Chemical Company, Midland, MI 48674, USA
| | | | | | - Carol Mohler
- The Dow Chemical Company, Midland, MI 48674, USA
| | - Tao Wei
- Department of Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA.
- Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA
| | - Tzu-Chi Kuo
- The Dow Chemical Company, Midland, MI 48674, USA
| | - Zhan Chen
- Department of Chemistry, University of Michigan, MI 48109, USA.
- Department of Macromolecular Science and Engineering, University of Michigan, MI 48109, USA
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5
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Ma YH, Li B, Wang C, Yang J, Han X, Lu X. Unsaturation effects on lipid transmembrane asymmetry. J Chem Phys 2024; 160:215102. [PMID: 38842495 DOI: 10.1063/5.0209950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 05/15/2024] [Indexed: 06/07/2024] Open
Abstract
Within cell plasma membranes, unsaturated lipids are asymmetrically distributed over the inner and outer leaflets, offering an attractive local structural feature. However, the mechanism to keep lipid transmembrane asymmetry and the closely related transmembrane movement (flip-flop) for unsaturated lipids remain poorly understood. Here, we applied sum frequency generation vibrational spectroscopy to investigate this lipid transmembrane asymmetry upon mimicking the cell membrane homeostatic processes. On the one hand, unsaturated lipids were found to hinder the flip-flop process and preserve lipid transmembrane asymmetry in model cell membranes, owing to the steric hindrance caused by their bent tails. On the other hand, local unsaturated lipids in the mixed unsaturated/saturated lipid bilayer were conducive to the formation of the local asymmetry. Therefore, lipid unsaturation can be recognized as an intrinsic key factor to form and maintain lipid transmembrane asymmetry in cell membranes.
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Affiliation(s)
- Yong-Hao Ma
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Bolin Li
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Chu Wang
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jingjing Yang
- Department of Biochemistry and Molecular Biology, School of Medicine and Holistic Integrative Medicine, Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xiaofeng Han
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xiaolin Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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Pei Q, Zheng X, Tan J, Luo Y, Ye S. Probing the Local Near-Field Intensity of Plasmonic Nanoparticles in the Mid-infrared Spectral Region. J Phys Chem Lett 2024; 15:5390-5396. [PMID: 38739421 DOI: 10.1021/acs.jpclett.4c00964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
The enhanced local field of gold nanoparticles (AuNPs) in mid-infrared spectral regions is essential for improving the detection sensitivity of vibrational spectroscopy and mediating photochemical reactions. However, it is still challenging to measure its intensity at subnanometer scales. Here, using the NO2 symmetric stretching mode (νNO2) of self-assembled 4-nitrothiophenol (4-NTP) monolayers on AuNPs as a model, we demonstrated that the percentage of excited νNO2 mode, determined by femtosecond time-resolved sum-frequency generation vibrational spectroscopy, allows us to directly detect the local field intensity of the AuNP surface in subnanometer ranges. The local-field intensity is tuned by AuNP diameters. An approximate 17-fold enhancement was observed for the local field on 80 nm AuNPs compared to the Au film. Additionally, the local field can regulate the anharmonicity of the νNO2 mode by synergistic effect with molecular orientation. This work offers a promising approach to probe the local field intensity distribution around plasmonic NP surfaces at subnanometer scales.
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Affiliation(s)
- Quanbing Pei
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoxuan Zheng
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Junjun Tan
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Yi Luo
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Shuji Ye
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
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Labrague G, Gomez F, Chen Z. Characterization of Buried Interfaces of Silicone Materials in Situ to Understand Their Fouling-Release, Antifouling, and Adhesion Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9345-9361. [PMID: 38669686 DOI: 10.1021/acs.langmuir.4c00615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Poly(dimethylsiloxane) (PDMS) has numerous excellent properties and is extensively used as the main component of many silicone products in a variety of research fields and practical applications such as biomedical materials, aviation, construction, electronic devices, and automobiles. Interfacial structures of PDMS and other components in silicone systems are important for such research and applications. It is difficult to probe interfacial molecular structures of buried solid-liquid and solid-solid interfaces of silicone materials due to the lack of appropriate analytical tools. In this feature article, we presented our research on elucidating the molecular structures of PDMS as well as other additives in silicone samples at buried interfaces in situ at the molecular level using a nonlinear optical spectroscopic technique, sum frequency generation (SFG) vibrational spectroscopy. SFG was applied to study various PDMS surfaces in liquid environments to understand their fouling-release and antifouling activities. SFG has also been used to study buried solid-solid interfaces between silicone adhesives and polymers, elucidating the molecular adhesion mechanisms. Our SFG studies provide important knowledge on interfacial structure-function relationships of silicone materials, helping the design and development of silicone materials with improved properties through optimization of silicone interfacial structures.
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Affiliation(s)
- Gladwin Labrague
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Fernando Gomez
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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Xu Z, Li G, Zhang Y, Wu Y, Lu X. Probing Interfacial Aging of Model Adhesion Joints under a Hygrothermal Environment at a Molecular Level. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9280-9288. [PMID: 38619299 DOI: 10.1021/acs.langmuir.4c00696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Generally, for adhesive joints, the polar water molecules in humid environments can have a critical effect on the interfacial structures and structural evolution adjacent to the solid substrates. Regarding this, it is still a big challenge to detect and understand the interfacial hygrothermal aging process at the molecular level in real time and in situ. In this study, to trace the interfacial hygrothermal aging process of a classical epoxy formula containing diglycidyl ether of biphenyl A (DGEBA) and 2,2'-(ethylenedioxy) diethylamine (EDDA) with sapphire and fused silica in a typical hygrothermal environment (85 °C and 85% RH), sum frequency generation (SFG) vibrational spectroscopy was used to probe the molecular-level interfacial structural change over the time. The structural evolution dynamics at the buried epoxy/sapphire and epoxy/silica interfaces upon hygrothermal aging were revealed directly in situ. The interfacial delamination during hygrothermal aging was also elucidated from the molecular level. Upon hygrothermal aging, the interfacial CH signals, such as the ones from methyl, methylene, and phenyl groups, decreased significantly and the water OH signals increased substantially, indicating the water molecules had diffused into the interfaces and destroyed the original interactions between the epoxy formula and the substrates. Further analysis indicates that when the integrated signals in the CH range declined to their minimum and leveled off, the interfacial delamination happened. The tensile experiment proved the validity of these spectroscopic experimental results. Our study provides first-hand and molecular-level evidence on a direct correlation between the diffusion of the surrounding water molecules into the interface and the evolution/destruction of the interfacial structures during hygrothermal aging. More importantly, it is proved, SFG can be developed into a powerful tool to noninvasively reveal the local interfacial delamination in real time and in situ under extreme hygrothermal conditions, complemented by the mechanic test.
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Affiliation(s)
- Zhaohui Xu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Gaoming Li
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yinyu Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yeping Wu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China
| | - Xiaolin Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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Kumaki J. In Situ Real-Time Atomic Force Microscopy Observations of Chain Mobility at Polymer/Water Interfaces of Poly(methyl methacrylate), Poly(2-hydroxyethyl methacrylate), and Poly(2-methoxyethyl methacrylate) Films in Water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5270-5277. [PMID: 38422988 DOI: 10.1021/acs.langmuir.3c03699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Polymer materials are widely used in water or in contact with an aqueous environment. However, evaluating the chain mobility, a crucial parameter, at a polymer-water interface is challenging. In this study, we, for the first time, observed poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(2-methoxyethyl methacrylate) (PMEMA) film surfaces in water via in situ real-time atomic force microscopy (AFM) in tapping mode and quantified the chain mobility. The average displacement between adjacent images (nm/8.75 min) was evaluated using particle image velocimetry. The displacement of PMMA, which has a high bulk glass-transition temperature (Tg) (108 °C) and exhibits limited water absorption, was low both in air (0.54 nm/8.75 min) and water (0.86), while PHEMA, which has a high bulk Tg (99 °C) and exhibits high water absorption, exhibited low mobility in air (0.40) but two orders of magnitude higher mobility in water (60). PMEMA, which has a low bulk Tg (14 °C) and exhibits limited water absorption, already started to move in air (4.5), and its mobility moderately increased in water (20). These behaviors were reasonable, considering the bulk Tg and water absorption characteristics of the polymers. Further, the chain mobility in water was compared with that of dried samples at high temperatures in air. The mobility of PMMA, PHEMA, and PMEMA in water corresponded to that of the dried samples observed in air below the surface Tg (97 °C) for PMMA, at ∼125 °C for PHEMA, and at ∼35 °C for PMEMA. In situ real-time AFM analysis of polymer materials in water is an effective method for evaluating the chain mobility at the polymer/water interface.
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Affiliation(s)
- Jiro Kumaki
- Emeritus Professor, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
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Mengel SD, Guo W, Wu G, Finlay JA, Allen P, Clare AS, Medhi R, Chen Z, Ober CK, Segalman RA. Diffusely Charged Polymeric Zwitterions as Loosely Hydrated Marine Antifouling Coatings. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:282-290. [PMID: 38131624 DOI: 10.1021/acs.langmuir.3c02492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Polymeric zwitterions exhibit exceptional fouling resistance through the formation of a strongly hydrated surface of immobilized water molecules. While being extensively tested for their performance in biomedical, membrane, and, to a lesser extent, marine environments, few studies have investigated how the molecular design of the zwitterion may enhance its performance. Furthermore, while theories of zwitterion antifouling mechanisms exist for molecular-scale foulant species (e.g., proteins and small molecules), it remains unclear how molecular-scale mechanisms influence the micro- and macroscopic interactions of relevance for marine applications. The present study addresses these gaps through the use of a modular zwitterion chemistry platform, which is characterized by a combination of surface-sensitive sum frequency generation (SFG) vibrational spectroscopy and marine assays. Zwitterions with increasingly delocalized cations demonstrate improved fouling resistance against the green alga Ulva linza. SFG spectra correlate well with the assay results, suggesting that the more diffuse charges exhibit greater surface hydration with more bound water molecules. Hence, the number of bound interfacial water molecules appears to be more influential in determining the marine antifouling activities of zwitterionic polymers than the binding strength of individual water molecules at the interface.
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Affiliation(s)
- Shawn D Mengel
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Wen Guo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48103, United States
| | - Guangyao Wu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48103, United States
| | - John A Finlay
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Peter Allen
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Anthony S Clare
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Riddhiman Medhi
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14583, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48103, United States
| | - Christopher K Ober
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14583, United States
| | - Rachel A Segalman
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department of Materials, University of California, Santa Barbara, California 93106, United States
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States
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11
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Wu Y, Wang T, Fay JDB, Zhang L, Hirth S, Hankett J, Chen Z. Silane Effects on Adhesion Enhancement of 2K Polyurethane Adhesives. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:19016-19026. [PMID: 38085956 DOI: 10.1021/acs.langmuir.3c03166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
With excellent properties such as great flexibility, outstanding chemical resistance, and superb mechanical strength, two-part polyurethane (2K PU) adhesives have been widely applied in many applications, including those in transportation and construction. Despite the extensive use, their adhesion to nonpolar polymer substrates still needs to be improved and has been widely studied. The incorporation of silane molecules and the use of plasma treatment on substrate surfaces are two popular methods to increase the adhesion of 2K PU adhesives, but their detailed adhesion enhancement mechanisms are still largely unknown. In this research, sum frequency generation (SFG) vibrational spectroscopy was used to probe the influence of added or coated silanes on the interfacial structure at the buried polypropylene (PP)/2K PU adhesive interface in situ. How plasma treatment on PP could improve adhesion was also investigated. To achieve maximum adhesion, two methods to involve silanes were studied. In the first method, silanes were directly mixed with the 2K PU adhesive before use. In the second method, silane molecules were spin-coated onto the PP substrate before the PU adhesive applied. It was found that the first method could not improve the 2K PU adhesion to PP, while the second method could substantially enhance such adhesion. SFG studies demonstrated that with the second method silane molecules chemically reacted at the interface to connect PP and 2K PU adhesive to improve the adhesion. With the first method, silane molecules could not effectively diffuse to the interface to enhance adhesion. In this research, plasma treatment was also found to be a useful method to improve the adhesion of the 2K PU adhesive to nonpolar polymer materials.
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Affiliation(s)
- Yuchen Wu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Tianle Wang
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Jonathan D B Fay
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Lu Zhang
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Sabine Hirth
- Material Physics and Analytics - B007, BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen am Rhein, Germany
| | - Jeanne Hankett
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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12
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Kaur S, Tomar D, Chaudhary M, Rana B, Kaur H, Nigam V, Jena KC. Interfacial molecular structure of phosphazene-based polymer electrolyte at the air-aqueous interface using sum frequency generation vibrational spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:105001. [PMID: 37988750 DOI: 10.1088/1361-648x/ad0e94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/21/2023] [Indexed: 11/23/2023]
Abstract
The change induced in the physicochemical properties of polymer while hosting ions provides a platform for studying its potential applications in electrochemical devices, water treatment plants, and materials engineering science. The ability to host ions is limited in very few polymers, which lack a detailed molecular-level understanding for showcasing the polymer-ion linkage behavior at the interfacial region. In the present manuscript, we have employed sum frequency generation (SFG) vibrational spectroscopy to investigate the interfacial structure of a new class phosphazene-based methoxyethoxyethoxyphosphazene (MEEP) polymer in the presence of lithium chloride salt at the air-aqueous interface. The interfacial aspects of the molecular system collected through SFG spectral signatures reveal enhanced water ordering and relative hydrogen bonding strength at the air-aqueous interface. The careful observation of the study finds a synchronous contribution of van der Waals and electrostatic forces in facilitating changes in the interfacial water structure that are susceptible to MEEP concentration in the presence of ions. The observation indicates that dilute MEEP concentrations support the role of electrostatic interaction, leading to an ordered water structure in proximity to diffused ions at the interfacial region. Conversely, higher MEEP concentrations promote the dominance of van der Waals interactions at the air-aqueous interface. Our study highlights the establishment of polymer electrolyte (PE) characteristics mediated by intermolecular interactions, as observed through the spectral signatures witnessed at the air-aqueous interface. The investigation illustrates the polymer-ion linkage adsorption effects at the interfacial region, which explains the macroscopic changes observed from the cyclic voltammetry studies. The fundamental findings from our studies can be helpful in the design and fine-tuning of better PE systems that can offer improved hydrophobic membranes and interface stability for use in electrochemical-based power sources.
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Affiliation(s)
- Sarabjeet Kaur
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Deepak Tomar
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Monika Chaudhary
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Bhawna Rana
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Harsharan Kaur
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Vineeta Nigam
- Defence Materials Stores Research and Development Establishment, Kanpur 208013, India
| | - Kailash C Jena
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
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13
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Gao J, Stengel P, Lu T, Wu Y, Hawker DD, Gutowski KE, Hankett JM, Kellermeier M, Chen Z. Antiadhesive Copolymers at Solid/Liquid Interfaces: Complementary Characterization of Polymer Adsorption and Protein Fouling by Sum Frequency Generation Vibrational Spectroscopy and Quartz-Crystal Microbalance Measurements with Dissipation Monitoring. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12270-12282. [PMID: 37586045 DOI: 10.1021/acs.langmuir.3c01759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Amphiphilic copolymers comprising hydrophilic segments of poly(ethylene glycol) and hydrophobic domains that are able to adhere to solid/liquid interfaces have proven to be versatile ingredients in formulated products for various types of applications. Recently, we have reported the successful synthesis of a copolymer designed for modifying the surface properties of polyesters as mimics for synthetic textiles. Using sum frequency generation (SFG) spectroscopy, it was shown that the newly developed copolymer adsorbs effectively on the targeted substrates even in the presence of surfactants as supplied by common detergents. In the present work, these studies were extended to evaluate the ability of the formed copolymer adlayers to passivate polyester surfaces against undesired deposition of bio(macro)molecules, as represented by fibrinogen as model protein foulants. In addition, SFG spectroscopy was used to elucidate the structure of fibrinogen at the interface between polyester and water. To complement the obtained data with an independent technique, analogous experiments were performed using quartz-crystal microbalance with dissipation monitoring for the detection of the relevant interfacial processes. Both methods give consistent results and deliver a holistic picture of brush copolymer adsorption on polyester surfaces and subsequent antiadhesive effects against proteins under different conditions representing the targeted application in home care products.
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Affiliation(s)
- Jinpeng Gao
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Peter Stengel
- Material Science, BASF SE, RGA/BM - B007, Carl-Bosch-Strasse 38, D-67056 Ludwigshafen, Germany
| | - Tieyi Lu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Yuchen Wu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Dustin D Hawker
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Keith E Gutowski
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Jeanne M Hankett
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Matthias Kellermeier
- Material Science, BASF SE, RGA/BM - B007, Carl-Bosch-Strasse 38, D-67056 Ludwigshafen, Germany
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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14
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Ma Y, Gong J, Zeng P, Liu M. Recent Progress in Interfacial Dipole Engineering for Perovskite Solar Cells. NANO-MICRO LETTERS 2023; 15:173. [PMID: 37420117 PMCID: PMC10328907 DOI: 10.1007/s40820-023-01131-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/26/2023] [Indexed: 07/09/2023]
Abstract
Design and modification of interfaces have been the main strategies in developing perovskite solar cells (PSCs). Among the interfacial treatments, dipole molecules have emerged as a practical approach to improve the efficiency and stability of PSCs due to their unique and versatile abilities to control the interfacial properties. Despite extensive applications in conventional semiconductors, working principles and design of interfacial dipoles in the performance/stability enhancement of PSCs are lacking an insightful elucidation. In this review, we first discuss the fundamental properties of electric dipoles and the specific roles of interfacial dipoles in PSCs. Then we systematically summarize the recent progress of dipole materials in several key interfaces to achieve efficient and stable PSCs. In addition to such discussions, we also dive into reliable analytical techniques to support the characterization of interfacial dipoles in PSCs. Finally, we highlight future directions and potential avenues for research in the development of dipolar materials through tailored molecular designs. Our review sheds light on the importance of continued efforts in this exciting emerging field, which holds great potential for the development of high-performance and stable PSCs as commercially demanded.
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Affiliation(s)
- Yinyi Ma
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, People's Republic of China
| | - Jue Gong
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, People's Republic of China
| | - Peng Zeng
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, People's Republic of China
| | - Mingzhen Liu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, People's Republic of China.
- State Key Laboratory Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 611731, People's Republic of China.
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15
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Rana B, Fairhurst DJ, Jena KC. Ion-Specific Water-Macromolecule Interactions at the Air/Aqueous Interface: An Insight into Hofmeister Effect. J Am Chem Soc 2023; 145:9646-9654. [PMID: 37094217 DOI: 10.1021/jacs.3c00701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
The specificity of ions in inducing conformational changes in macromolecules is introduced as the Hofmeister series; however, the detailed underlying mechanism is not comprehensible yet. We utilized surface-specific sum frequency generation (SFG) vibrational spectroscopy to explore the Hofmeister effect at the air/polyvinylpyrrolidone (PVP)/water interface. The spectral signature observed from the ssp polarization scheme reveals ion-specific ordering of water molecules following the Hofmeister series attributed to the ion-macromolecule interactions. Along with this, the presence of ions does not reflect any significant influence on the structure of the PVP macromolecule. However, the ppp-SFG spectra in the CH-stretch region reveal the impact of ions on the orientation angle of vinyl chain CH2-groups, which follows the Hofmeister series: SO42- > Cl- > NO3- > Br- > ClO4- > SCN-. The minimal orientation angle of CH2-groups indicates significant reordering in PVP vinyl chains in the presence of chaotropic anions ClO4-, and SCN-. The observation is attributed to the ion-specific water-macromolecule interactions at the air/aqueous interface. It is compelling to observe the signature of spectral blue shifts in the OH-stretch region in the ppp configuration in the presence of chaotropic anions. The origin of spectral blue shifts has been ascribed to the existence of weaker interactions between the interfacial water molecules and the backbone CH- and CH2-moieties of the PVP macromolecules. The ion-specific modulation in water-macromolecule interactions is endorsed by the relative propensity of anion's adsorption toward the air/aqueous interface. The experimental findings highlight the existence and cooperative participation of ion-specific water-macromolecule interactions in the mechanism of the Hofmeister effect, along with the illustrious ion-water and ion-macromolecule interactions.
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Affiliation(s)
- Bhawna Rana
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - David J Fairhurst
- Department of Physics and Mathematics, School of Science and Technology, Nottingham Trent University, Clifton Campus, Nottingham NG11 8NS, U.K
| | - Kailash C Jena
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
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16
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Gao J, Khan MR, Wu Y, Hawker DD, Gutowski KE, Konradi R, Mayr L, Hankett JM, Kellermeier M, Chen Z. Probing Interfacial Behavior and Antifouling Activity of Adsorbed Copolymers at Solid/Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4557-4570. [PMID: 36947877 DOI: 10.1021/acs.langmuir.2c03056] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Polymers containing poly(ethylene glycol) (PEG) units can exhibit excellent antifouling properties, which have been proposed/used for coating of biomedical implants, separation membranes, and structures in marine environments, as well as active ingredients in detergent formulations to avoid soil redepositioning in textile laundry. This study aimed to elucidate the molecular behavior of a copolymer poly(MMA-co-MPEGMA) containing antiadhesive PEG side chains and a backbone of poly(methyl methacrylate), at a buried polymer/solution interface. Polyethylene terephthalate (PET) was used as a substrate to model polyester textile surfaces. Sum frequency generation (SFG) vibrational spectroscopy was applied to examine the interfacial behavior of the copolymer at PET/solution interfaces in situ and in real time. Complementarily, copolymer adsorption on PET and subsequent antiadhesion against protein foulants were probed by quartz-crystal microbalance experiments with dissipation monitoring (QCM-D). Both applied techniques show that poly(MMA-co-MPEGMA) adsorbs significantly to the PET/solution interface at bulk polymer solution concentrations as low as 2 ppm, while saturation of the surface was reached at 20 ppm. The hydrophobic MMA segments provide an anchor for the copolymer to bind onto PET in an ordered way, while the pendant PEG segments are more disordered but contain ordered interfacial water. In the presence of considerable amounts of dissolved surfactants, poly(MMA-co-MPEGMA) could still effectively adsorb on the PET surface and remained stable at the surface upon washing with hot and cold water or surfactant solution. In addition, it was found that adsorbed poly(MMA-co-MPEGMA) provided the PET surface with antiadhesive properties and could prevent protein deposition, highlighting the superior surface affinity and antifouling performance of the copolymer. The results obtained in this work demonstrate that amphiphilic copolymers containing PMMA anchors and PEG side chains can be used in detergent formulations to modify polyester surfaces during laundry and reduce deposition of proteins (and likely also other soils) on the textile.
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Affiliation(s)
- Jinpeng Gao
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Md Rubel Khan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yuchen Wu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Dustin D Hawker
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Keith E Gutowski
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Rupert Konradi
- Biointerfaces & Delivery Systems, BASF SE, Carl-Bosch-Strasse 38, Ludwigshafen D-67056, Germany
| | - Lukas Mayr
- Material Physics, BASF SE, RAA/OS - B007, Carl-Bosch-Strasse 38, Ludwigshafen D-67056, Germany
| | - Jeanne M Hankett
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Matthias Kellermeier
- Material Physics, BASF SE, RAA/OS - B007, Carl-Bosch-Strasse 38, Ludwigshafen D-67056, Germany
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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17
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Guo W, Lu T, Crisci R, Nagao S, Wei T, Chen Z. Determination of protein conformation and orientation at buried solid/liquid interfaces. Chem Sci 2023; 14:2999-3009. [PMID: 36937592 PMCID: PMC10016606 DOI: 10.1039/d2sc06958j] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Protein structures at solid/liquid interfaces mediate interfacial protein functions, which are important for many applications. It is difficult to probe interfacial protein structures at buried solid/liquid interfaces in situ at the molecular level. Here, a systematic methodology to determine protein molecular structures (orientation and conformation) at buried solid/liquid interfaces in situ was successfully developed with a combined approach using a nonlinear optical spectroscopic technique - sum frequency generation (SFG) vibrational spectroscopy, isotope labeling, spectra calculation, and computer simulation. With this approach, molecular structures of protein GB1 and its mutant (with two amino acids mutated) were investigated at the polymer/solution interface. Markedly different orientations and similar (but not identical) conformations of the wild-type protein GB1 and its mutant at the interface were detected, due to the varied molecular interfacial interactions. This systematic strategy is general and can be widely used to elucidate protein structures at buried interfaces in situ.
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Affiliation(s)
- Wen Guo
- Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor 48109 Michigan USA
| | - Tieyi Lu
- Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor 48109 Michigan USA
| | - Ralph Crisci
- Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor 48109 Michigan USA
| | - Satoshi Nagao
- Graduate School of Science, University of Hyogo 3-2-1 Koto, Ako-gun Kamigouri-cho Hyogo 678-1297 Japan
| | - Tao Wei
- Department of Chemical Engineering, Howard University 2366 Sixth Street NW Washington 20059 DC USA
| | - Zhan Chen
- Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor 48109 Michigan USA
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18
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Wu Y, Wang T, Gao J, Zhang L, Fay JDB, Hirth S, Hankett J, Chen Z. Molecular Behavior of 1K Polyurethane Adhesive at Buried Interfaces: Plasma Treatment, Annealing, and Adhesion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:3273-3285. [PMID: 36808974 DOI: 10.1021/acs.langmuir.2c03084] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
One-part (1K) polyurethane (PU) adhesive has excellent bulk strength and environmental resistance. It is therefore widely used in many fields, such as construction, transportation, and flexible lamination. However, when contacting non-polar polymer materials, the poor adhesion of 1K PU adhesive may not be able to support its outdoor applications. To solve this problem, plasma treatment of the non-polar polymer surface has been utilized to improve adhesion between the polymer and 1K PU adhesive. The detailed mechanisms of adhesion enhancement of the 1K PU adhesive caused by plasma treatment on polymer substrates have not been studied extensively because adhesion is a property of buried interfaces which are difficult to probe. In this study, sum frequency generation (SFG) vibrational spectroscopy was used to investigate the buried PU/polypropylene (PP) interfaces in situ nondestructively. Fourier-transform infrared spectroscopy, the X-ray diffraction technique, and adhesion tests were used as supplemental methods to SFG in the study. The 1K PU adhesive is a moisture-curing adhesive and usually needs several days to be fully cured. Here, time-dependent SFG experiments were conducted to monitor the molecular behaviors at the buried 1K PU adhesive/PP interfaces during the curing process. It was found that the PU adhesives underwent rearrangement during the curing process with functional groups gradually becoming ordered at the interface. Stronger adhesion between the plasma-treated PP substrate and the 1K PU adhesive was observed, which was achieved by the interfacial chemical reactions and a more rigid interface. Annealing the samples increased the reaction speed and enhanced the bulk PU strength with higher crystallinity. In this research, molecular mechanisms of adhesion enhancement of the 1K PU adhesive caused by the plasma treatment on PP and by annealing the PU/PP samples were elucidated.
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Affiliation(s)
- Yuchen Wu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Tianle Wang
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jinpeng Gao
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Lu Zhang
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Jonathan D B Fay
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Sabine Hirth
- BASF SE, RAA/OS-B007, Carl-Bosch-Strasse 38, 67056 Ludwigshafen am Rhein, Germany
| | - Jeanne Hankett
- BASF Corporation, 1609 Biddle Avenue, Wyandotte, Michigan 48192, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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19
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Wang C, Ma YH, Han X, Lu X. Re-Examining Interaction between Antimicrobial Peptide Aurein 1.2 and Model Cell Membranes via SFG. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:690-699. [PMID: 36576332 DOI: 10.1021/acs.langmuir.2c03068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Aurein 1.2 (Aur), a highly efficient 13-residue antimicrobial peptide (AMP) with a broad-spectrum antibiotic activity originally derived from the Australian frog skin secretions, can nonspecifically disrupt bacterial membranes. To deeply understand the molecular-level detail of the antimicrobial mechanism, here, we artificially established comparative experimental models to investigate the interfacial interaction process between Aur and negatively charged model cell membranes via sum frequency generation vibrational spectroscopy. Sequencing the vibrational signals of phenyl, C-H, and amide groups from Aur has characteristically helped us differentiate between the initial adsorption and subsequent insertion steps upon mutual interaction between Aur and the charged lipids. The phenyl group at the terminal phenylalanine residue can act as an anchor in the adsorption process. The time-dependent signal intensity of α-helices showed a sharp rise once the Aur molecules came into contact with the negatively charged lipids, indicating that the adsorption process was ongoing. Insertion of Aur into the charged lipids then offered the detectable interfacial C-H signals from Aur. The achiral and chiral amide I signals suggest that Aur had formed β-folding-like aggregates after interacting with the charged lipids, along with the subsequent descending α-helical amide I signals. The above-mentioned experimental results provide the molecular-level detail on how the Aur molecules interact with the cell membranes, and such a mechanism study can offer the necessary support for the AMP design and later application.
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Affiliation(s)
- Chu Wang
- State Key Laboratory of Bioelectronics, School of Biomedical Engineering, Southeast University, Nanjing 210096, China
| | - Yong-Hao Ma
- State Key Laboratory of Bioelectronics, School of Biomedical Engineering, Southeast University, Nanjing 210096, China
| | - Xiaofeng Han
- State Key Laboratory of Bioelectronics, School of Biomedical Engineering, Southeast University, Nanjing 210096, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biomedical Engineering, Southeast University, Nanjing 210096, China
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20
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Kaur H, Verma M, Kaur S, Rana B, Singh N, Jena KC. Elucidating the Molecular Structure of Hydrophobically Modified Polyethylenimine Nanoparticles and Its Potential Implications for DNA Binding. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13456-13468. [PMID: 36279506 DOI: 10.1021/acs.langmuir.2c01912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The structural properties of the polyethylenimine (PEI) polymer are generally tuned and selectively modified to reinforce its potential in a broad spectrum of applied domains of medicine, healthcare, material design, sensing, and electronic optimization. The selective modification of the polymer brings about changes in its interfacial characteristics and behavior. The current work involves the synthesis of naphthalimide conjugated polyethylenimine organic nanoparticles (NPEI-ONPs). The interfacial molecular structure of NPEI-ONPs is explored in an aqueous medium at pH 7.4 using surface tensiometry and sum-frequency generation vibrational spectroscopy (SFG-VS). The hydrophobic functionalization rendered a concentration-dependent surface coverage of NPEI-ONPs, where the SFG-VS analysis exhibited the molecular rearrangement of its hydrophobic groups at the interface. The interaction of NPEI-ONPs with double-stranded DNA (dsDNA) is carried out to observe the relevance of the synthesized nanocomposites in the biomedical domain. The bulk-specific studies (i.e., thermal denaturation, viscometry, zeta (ζ) potential, and ATR-FTIR) reveal the condensation of dsDNA in the presence of NPEI-ONPs, making its structure more compact. The interface-sensitive SFG-VS showcased the impact of the dsDNA and NPEI-ONP interaction on the interfacial molecular behavior of NPEI-ONPs at the air-aqueous interface. Our results exhibit the potential of such hydrophobically functionalized ONPs as promising candidates for developing biomedical sealants, substrate coatings, and other biomedical domains.
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21
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Xu Z, Zhang Y, Wu Y, Lu X. Spectroscopically Detecting Molecular-Level Bonding Formation between an Epoxy Formula and Steel. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13261-13271. [PMID: 36254887 DOI: 10.1021/acs.langmuir.2c02325] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The formation of the interfacial adhesion between an epoxy adhesive and a substrate was normally accompanied by the epoxy curing process on the substrate. Although the debate on the formation mechanism of the interfacial adhesion is still ongoing, this issue can causally be resolved by studying the interfacial structural formation between the epoxy adhesive and the substrate. Herein, to reveal the interfacial structural formation of a representative formula composed of epoxy (digylcidyl ether of biphenyl A, DGEBA) and amine hardener (2,2'-(ethylenedioxy) diethylamine, EDDA) with the steel substrate upon curing and postcuring treatments, sum-frequency generation (SFG) vibrational spectroscopy with a sandwiched transparent window/epoxy adhesive/steel setup was applied to detect and track the buried molecular-level structures at the epoxy adhesive/steel interface. An X-ray photoelectron spectroscopic (XPS) experiment was performed to probe the intentionally exposed interface to disclose the occurring interfacial chemical reaction. The reaction between the epoxy groups and the steel-surface OH groups and the molecular reconstruction of interfacial epoxy methyl groups upon curing and postcuring steps were confirmed. The latter also indirectly indicated the formation of the additional hydrogen bonding and the former bonding reaction at the interface. The above two spectroscopic experimental results matched up with the further examination of the adhesion strength. Therefore, this work elucidates the formation of the interfacial bonding between the epoxy formula and the steel substrate upon curing and postcuring treatments at the molecular level, thus providing an in-depth insight into the origin of the interfacial adhesion.
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Affiliation(s)
- Zhaohui Xu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Yinyu Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang621900, China
| | - Yeping Wu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang621900, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
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22
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Lu T, Fu L, Qiu Y, Zhang J, Chen Z. Probing Molecular Interactions of Antibody Drugs, Silicone Oil, and Surfactant at Buried Interfaces In Situ. Anal Chem 2022; 94:14761-14768. [PMID: 36215703 DOI: 10.1021/acs.analchem.2c03425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibody drugs have been rapidly developed to cure many diseases including COVID-19 infection. Silicone oil is commonly used as a lubricant coating material for devices used in the pharmaceutical industry to store and administer antibody drug formulations. However, the interaction between silicone oil and antibody molecules could lead to the adsorption, denaturation, and aggregation of antibody molecules, impacting the efficacy of antibody drugs. Here, we studied the molecular interactions between antibodies and silicone oil in situ in real time. The effect of the surfactant on such interactions was also investigated. Specifically, the adsorption dynamics of a bispecific antibody (BsAb) onto a silicone oil surface without and with different concentrations of the surfactant PS80 in antibody solutions were monitored. Also the possible lowest effective PS80 concentrations that can prevent the adsorption of BsAb as well as a monoclonal antibody (mAb) onto silicone oil were measured. It was found that different concentrations of PS80 are required for preventing the adsorption of different antibodies. Both BsAB and mAB denature on silicone oil without a surfactant. However, for a low surfactant concentration in the solution, although the surfactant could not completely prevent the antibody from adsorption, it could maintain the native structures of adsorbed BsAb and mAb antibodies on silicone oil. This is important knowledge, showing that to prevent antibody aggregation on silicone oil it is not necessary to add surfactant to a concentration high enough to completely minimize protein adsorption.
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Affiliation(s)
- Tieyi Lu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Li Fu
- Sanofi, 1 The Mountain Road, Framingham, Massachusetts 01701, United States
| | - Yu Qiu
- Sanofi, 350 Water St, Cambridge, Massachusetts 02141, United States
| | - Jifeng Zhang
- Sanofi, 1 The Mountain Road, Framingham, Massachusetts 01701, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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23
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Du R, Li X, Ma YH, Luo Y, Wang C, Ma Q, Lu X. Exploring Interfacial Hydrolysis of Artificial Neutral Lipid Monolayer and Bilayer Catalyzed by Phospholipase C. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8104-8113. [PMID: 35749224 DOI: 10.1021/acs.langmuir.2c00995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phospholipase C (PLC) represents an important type of enzymes with the feature of hydrolyzing phospholipids at the position of the glycerophosphate bond, among which PLC extracted from Bacillus cereus (BC-PLC) has been extensively studied owing to its similarity to hitherto poorly characterized mammalian analogues. This study focuses on investigating the interfacial hydrolysis mechanism of phosphatidylcholine (PC) monolayer and bilayer membranes catalyzed by BC-PLC using sum frequency generation vibrational spectroscopy (SFG-VS) and laser scanning confocal microscopy (LSCM). We found that, upon interfacial hydrolysis, BC-PLC was adsorbed onto the lipid interface and catalyzed the lipolysis with no net orientation, as evidenced by the silent amide I band, indicating that ordered PLC alignment was not a prerequisite for the enzyme activity, which is very different from what we have reported for phospholipase A1 (PLA1) and phospholipase A2 (PLA2) [Kai, S. Phys. Chem. Chem. Phys. 2018, 20(1), 63-67; Wang, F. Langmuir 2019, 35(39), 12831-12838; Zhang, F. Langmuir 2020, 36(11), 2946-2953]. For the PC monolayer, one of the two hydrolysates, phosphocholine, desorbed from the interface into the aqueous phase, while the other one, diacylglycerol (DG), stayed well packed with high order at the interface. For the PC bilayer, phosphocholine dispersed into the aqueous phase too, similar to the monolayer case; however, DG, presumably formed clusters with the unreacted lipid substrates and desorbed from the interface. With respect to both the monolayer and bilayer cases, mechanistic schematics were presented to illustrate the different interfacial hydrolysis processes. Therefore, this model experimental study in vitro provides significant molecular-level insights and contributes necessary knowledge to reveal the lipolysis kinetics with respect to PLC and lipid membranes with monolayer and bilayer structures.
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Affiliation(s)
- Rongrong Du
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Xu Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Yong-Hao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Yongsheng Luo
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Chu Wang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Qian Ma
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, P. R. China
- Department of General Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, P. R. China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
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Andre JS, Grant J, Greyson E, Chen X, Tucker C, Drumright R, Mohler C, Chen Z. Molecular Interactions between Amino Silane Adhesion Promoter and Acrylic Polymer Adhesive at Buried Silica Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6180-6190. [PMID: 35512318 DOI: 10.1021/acs.langmuir.2c00602] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this study, the influence of an amino silane (3-(2-aminoethylamino)-propyldimethoxymethylsilane, AEAPS) on the interfacial structure and adhesion of butyl acrylate/methyl methacrylate copolymers (BAMMAs) to silica was investigated by sum frequency generation vibrational spectroscopy (SFG). Small amounts of methacrylic acid, MAA, were included in the BAMMA polymerizations to assess the impact of carboxylic acid functionality on the glass interface. SFG was used to probe the O-H and C═O groups of incorporated MAA, ester C═O groups of BAMMA, and CH groups from all species at the silica interfaces. The addition of AEAPS resulted in a significant change in the molecular structure of the polymer at the buried interface with silica due to specific interactions between the BAMMA polymers and silane. SFG results were consistent with the formation of ionic bonds between the primary and secondary amines of the AEAPS tail group and the MAA component of the polymer, as evidenced by the loss of the MAA O-H and C═O signals at the interface. It is extensively reported in the literature that methoxy head groups of an amino silane chemically bind to the silanols of glass, leaving the amine groups available to react with various chemical functionalities. Our results are consistent with this scenario and support an adhesion promotion mechanism of amino silane with various aspects: (1) the ionic bond formation between the tail amine group and acid functionality on BAMMA, (2) the chemical coupling between the silane head group and glass, (3) migration of more ester C═O groups to the interface with order, and (4) disordering or reduced levels of CH groups at the interface. These results are important for better understanding of the mechanisms and effect of amino silanes on the adhesion between acrylate polymers and glass substrates in a variety of applications.
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Affiliation(s)
- John S Andre
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph Grant
- Dow Coating Materials, Collegeville, Pennsylvania 19426, United States
| | - Eric Greyson
- Dow Coating Materials, Collegeville, Pennsylvania 19426, United States
| | - Xiaoyun Chen
- The Dow Chemical Company, Core R&D, Midland, Michigan 48674, United States
| | - Christopher Tucker
- The Dow Chemical Company, Core R&D, Midland, Michigan 48674, United States
| | - Ray Drumright
- Dow Coating Materials, Midland, Michigan 48674, United States
| | - Carol Mohler
- The Dow Chemical Company, Core R&D, Midland, Michigan 48674, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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25
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Tan J, Pei Q, Zhang L, Ye S. Evidence for a Local Field Effect in Surface Plasmon-Enhanced Sum Frequency Generation Vibrational Spectra. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6099-6105. [PMID: 35499917 DOI: 10.1021/acs.langmuir.2c00457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface plasmon-enhanced vibrational spectroscopy has been demonstrated to be an important highly sensitive diagnostic technique, but its enhanced mechanism is yet to be explored. In this study, we couple femtosecond sum frequency generation vibrational spectroscopy (SFG-VS) with surface plasmon generated by the excitation of localized gold nanorods/nanoparticles and investigate the plasmonically enhanced factors (EFs) of SFG signals from poly(methyl methacrylate) films. Through monitoring the SFG intensity of carbonyl and ester methyl groups, we have established a correlation between EFs and the coupling of localized surface plasmon resonance with SFG and visible beams. It is found that the total enhanced factor is approximately proportional to the square of an enhanced factor of the SFG electromagnetic field and the fourth power of the enhanced factor of the visible electromagnetic field. The local field effect is roughly expressed to be the square of an enhanced factor of the visible electromagnetic field. This finding will help to guide the experimental design of plasmon-enhanced SFG to drastically improve the detection sensitivity and thus provide greater insight into the ultrafast dynamics near plasmonic surfaces.
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Affiliation(s)
- Junjun Tan
- Hefei National Research Center for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Quanbing Pei
- Hefei National Research Center for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Liang Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Shuji Ye
- Hefei National Research Center for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
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26
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Xu Z, Zhang Y, Wu Y, Lu X. Molecular-Level Correlation between Spectral Evidence and Interfacial Bonding Formation for Epoxy Adhesives on Solid Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5847-5856. [PMID: 35441517 DOI: 10.1021/acs.langmuir.2c00470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Interfacial bonding strength of an epoxy-based adhesive depends on the interfacial interaction between the adhesive and the substrate. Normally, the curing process at the interface accompanied by the interfacial bonding formation is different from that in the bulk, and it is still a big challenge to probe the interfacial bonding formation at a molecular level. In this study, to trace the interfacial structural evolution of a representative formula of epoxy (digylcidyl ether of biphenyl A, DGEBA) and amine hardener [1,2-bis(2-aminoethoxy)ethane, EDDA] with the sapphire and silica substrates upon curing and post-curing steps, sum frequency generation (SFG) vibrational spectroscopy is employed to detect the molecular-level interfacial structural information. For the sapphire substrate, upon curing, backbone methylene (CH2) stretching signals decrease, indicating the formation of a rigid chain network structure and thus losing the local methylene order, while vibrational signals of the sapphire surface hydroxyl (OH) groups (including hydrogen-bonded and unbonded) increase significantly, indicating the formation of a strong hydrogen-bonding and polar interaction between the epoxy adhesive and the sapphire surface. Upon post-curing, increased backbone CH2 signals and decreased sapphire OH signals suggest interfacial chemical bonding formation due to the reaction between the epoxy rings and the sapphire surface OH groups. Orientation analysis confirms the enhanced ordering of the sapphire surface OH groups upon curing and post-curing, in comparison to the uncured epoxy formula. As for the fused silica, weak vibrational signals of the methylene (CH2) and methyl (CH3) groups are observed before curing, while both of them increase slightly for the cured and post-cured epoxy formulae, suggesting relatively less hydrophilic nature of the silica surface compared to that of the sapphire surface, also evidenced by the very weak OH signals upon curing and post-curing. Further measurement on the adhesion strength matches up with the above spectroscopic experimental results, substantiating the correlation between the macroscopic bonding strength of the epoxy adhesive and the microscopic molecular-level structure.
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Affiliation(s)
- Zhaohui Xu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yinyu Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yeping Wu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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27
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Early sum frequency generation vibrational spectroscopic studies on peptides and proteins at interfaces. Biointerphases 2022; 17:031202. [PMID: 35525602 DOI: 10.1116/6.0001859] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This paper summarizes the early research results on studying proteins and peptides at interfaces using sum frequency generation (SFG) vibrational spectroscopy. SFG studies in the C-H stretching frequency region to examine the protein side-chain behavior and in the amide I frequency region to investigate the orientation and conformation of interfacial peptides/proteins are presented. The early chiral SFG research and SFG isotope labeling studies on interfacial peptides/proteins are also discussed. These early SFG studies demonstrate the feasibility of using SFG to elucidate interfacial molecular structures of peptides and proteins in situ, which built a foundation for later SFG investigations on peptides and proteins at interfaces.
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28
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Chen Z. Surface Hydration and Antifouling Activity of Zwitterionic Polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4483-4489. [PMID: 35380850 DOI: 10.1021/acs.langmuir.2c00512] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It is believed that the strong surface hydration of zwitterionic polymers leads to excellent antifouling properties. This Perspective presents the recent developments in studies on such surface hydration in situ using sum frequency generation (SFG) vibrational spectroscopy. SFG research provides direct molecular level evidence that zwitterionic polymers have strong surface hydration, which prevents protein adsorption and marine animal attachment. The salt effect and protein interaction on surface hydration of zwitterionic polymers have also been examined using SFG. Possible future research directions on surface hydration of new zwitterionic polymers including zwitterionic hydrogels, copolymers, and mixed charged polymers are discussed. It is also important to combine experimental SFG studies with computer simulations to further elucidate the surface hydration to understand antifouling mechanisms.
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Affiliation(s)
- Zhan Chen
- Departments of Chemistry and Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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Luo Y, Pang AP, Lu X. Liquid-Solid Interfaces under Dynamic Shear Flow: Recent Insights into the Interfacial Slip. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4473-4482. [PMID: 35377658 DOI: 10.1021/acs.langmuir.2c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The development of micro/nanofluidic techniques has recently revived interest in dynamic shear flow at liquid-solid interfaces. When the nature of the liquid-solid boundaries was revisited, the slip of the fluids relative to the solid wall was predicted theoretically and confirmed experimentally. This indicates that the molecular-level structures of the liquid-solid interfaces will be influenced by the liquid flow over certain temporal and spatial criteria. However, the fluid flow at the boundary layer still cannot be precisely predicted and effectively controlled, somehow limiting its practical applications. Here, we summarize the recent advances for the microscopic structures at the liquid-solid interfaces upon shear flow. Special attention was given to a second-order nonlinear optical technique, sum frequency generation vibrational spectroscopy, which is a powerful tool for exploring the molecular-level structures and structural dynamics at the liquid-solid interfaces and offering new insights into the molecular mechanisms of the fluid slip at the interfaces. Moreover, we discuss the possible approaches for controlling the interfacial slip at the molecular level and highlight the current challenges and opportunities. Although the theoretical framework of the slip at the liquid-solid interfaces is still incomplete, we hope that this Perspective will complement and enhance our understanding of various interfacial properties and phenomena with respect to practical non-equilibrium dynamic processes happening at the interfaces.
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Affiliation(s)
- Yongsheng Luo
- The State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu, P. R. China
| | - Ai-Ping Pang
- The State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu, P. R. China
| | - Xiaolin Lu
- The State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu, P. R. China
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30
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Sharafeldin M, Davis JJ. Characterising the biosensing interface. Anal Chim Acta 2022; 1216:339759. [DOI: 10.1016/j.aca.2022.339759] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/08/2022] [Accepted: 03/22/2022] [Indexed: 12/19/2022]
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31
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Lin T, Wu Y, Santos E, Chen X, Kelleher-Ferguson J, Tucker C, Ahn D, Mohler C, Chen Z. Probing Covalent Interactions at a Silicone Adhesive/Nylon Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:2590-2600. [PMID: 35166546 DOI: 10.1021/acs.langmuir.1c03218] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Covalent bonding is one of the most robust forms of intramolecular interaction between adhesives and substrates. In contrast to most noncovalent interactions, covalent bonds can significantly enhance both the interfacial strength and durability. To utilize the advantages of covalent bonding, specific chemical reactions are designed to occur at interfaces. However, interfacial reactions are difficult to probe in situ, particularly at the buried interfaces found in well-bonded adhesive joints. In this work, sum frequency generational (SFG) vibrational spectroscopy was used to directly examine and analyze the interfacial chemical reactions and related molecular changes at buried nylon/silicone elastomer interfaces. For self-priming elastomeric silicone adhesives, silane coupling agents have been extensively used as adhesion promoters. Here with SFG, the interfacial chemical reactions between nylon and two alkoxysilane adhesion promoters with varied functionalities (maleic anhydride (MAH) and epoxy) formulated into the silicone were observed and investigated. Evidence of reactions between the organofunctional group of each silane and reactive groups on the polyamide was found at the buried interface between the cured silicone elastomer and nylon. The adhesion strength at the nylon/cured silicone interfaces was substantially enhanced with both silane additives. SFG results elucidated the mechanisms of organo-silane adhesion promotion for silicone at the molecular level. The ability to probe and analyze detailed interfacial reactions at buried nylon/silicone interfaces demonstrated that SFG is a powerful analytical technique to aid the design and optimization of materials with desired interfacial properties.
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Affiliation(s)
| | | | - Elizabeth Santos
- Dow Performance Silicones, Auburn, Michigan 48611, United States
| | - Xiaoyun Chen
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | | | - Chris Tucker
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Dongchan Ahn
- Dow Performance Silicones, Auburn, Michigan 48611, United States
| | - Carol Mohler
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
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32
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Luo Y, Pang AP, Zhu P, Wang D, Lu X. Demonstrating the Interfacial Polymer Thermal Transition from Coil-to-Globule to Coil-to-Stretch under Shear Flow Using SFG and MD Simulation. J Phys Chem Lett 2022; 13:1617-1627. [PMID: 35142518 DOI: 10.1021/acs.jpclett.1c03866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Revealing interfacial shear-induced structural responsiveness has long been an important topic in that most fluids in nature and human life are in motion and cause interesting boundary phenomena. It is amazing how the polymer chain conformation or local structural features at a boundary change under the effective shear condition. In this study, microfluidic-assisted sum frequency generation (SFG) vibrational spectroscopy and all-atom molecular dynamics (MD) simulation are combined to reveal that the shear flow can effectively block the so-called thermal coil-to-globule transition of the poly(N-isopropylacrylamide) (PNIPAM) brushes on the solid substrate, and the normal coil-to-globule transition transfers to a coil-to-stretch one under shear flow with increasing ambient temperature. Such findings are attributed to the balance between the shear flow and the molecular interaction with respect to the polymer chains and adjacent water molecules, thus demonstrating the significant effect of the shear flow on the structural and dynamic behaviors of the polymer chains at the boundaries from the molecular level.
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Affiliation(s)
- Yongsheng Luo
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Ai-Ping Pang
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Peizhi Zhu
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, Jiangsu Province, P. R. China
| | - Dayang Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, Jilin Province, P. R. China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
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33
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Lu T, Guo W, Datar PM, Xin Y, Marsh ENG, Chen Z. Probing protein aggregation at buried interfaces: distinguishing between adsorbed protein monomers, dimers, and a monomer-dimer mixture in situ. Chem Sci 2022; 13:975-984. [PMID: 35211262 PMCID: PMC8790787 DOI: 10.1039/d1sc04300e] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/04/2021] [Indexed: 11/21/2022] Open
Abstract
Protein adsorption on surfaces greatly impacts many applications such as biomedical materials, anti-biofouling coatings, bio-separation membranes, biosensors, antibody protein drugs etc. For example, protein drug adsorption on the widely used lubricant silicone oil surface may induce protein aggregation and thus affect the protein drug efficacy. It is therefore important to investigate the molecular behavior of proteins at the silicone oil/solution interface. Such an interfacial study is challenging because the targeted interface is buried. By using sum frequency generation vibrational spectroscopy (SFG) with Hamiltonian local mode approximation method analysis, we studied protein adsorption at the silicone oil/protein solution interface in situ in real time, using bovine serum albumin (BSA) as a model. The results showed that the interface was mainly covered by BSA dimers. The deduced BSA dimer orientation on the silicone oil surface from the SFG study can be explained by the surface distribution of certain amino acids. To confirm the BSA dimer adsorption, we treated adsorbed BSA dimer molecules with dithiothreitol (DTT) to dissociate these dimers. SFG studies on adsorbed BSA after the DTT treatment indicated that the silicone oil surface is covered by BSA dimers and BSA monomers in an approximate 6 : 4 ratio. That is to say, about 25% of the adsorbed BSA dimers were converted to monomers after the DTT treatment. Extensive research has been reported in the literature to determine adsorbed protein dimer formation using ex situ experiments, e.g., by washing off the adsorbed proteins from the surface then analyzing the washed-off proteins, which may induce substantial errors in the washing process. Dimerization is a crucial initial step for protein aggregation. This research developed a new methodology to investigate protein aggregation at a solid/liquid (or liquid/liquid) interface in situ in real time using BSA dimer as an example, which will greatly impact many research fields and applications involving interfacial biological molecules.
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Affiliation(s)
- Tieyi Lu
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
| | - Wen Guo
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
| | - Prathamesh M Datar
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
| | - Yue Xin
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
| | - Zhan Chen
- Department of Chemistry, University of Michigan Ann Arbor Michigan 48109 USA
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Affiliation(s)
- Guido Raos
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via L. Mancinelli 7, I-20131 Milano, Italy
| | - Bruno Zappone
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR-Nanotec), Via P. Bucci, 33/C, 87036 Rende (CS), Italy
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35
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Zhang S, Hsu L, Toolis A, Li B, Zhou J, Lin T, Chen Z. Investigation of the Atmospheric Moisture Effect on the Molecular Behavior of an Isocyanate-Based Primer Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12705-12713. [PMID: 34668715 DOI: 10.1021/acs.langmuir.1c02135] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A primer coating is engineered to facilitate compatibility between products like adhesives, sealants, and potting compounds and targeted substrates. Prolonged exposure of isocyanate-based primer surfaces to the environment is known to negatively affect the interfacial adhesion between itself and the products subsequently applied on top of it. However, the molecular behavior behind this observed phenomenon remained to be further investigated. In this study, sum frequency generation (SFG) vibrational spectroscopy, a nonlinear optical spectroscopic technique, was applied to study the surface of an isocyanate-based primer exposed to different environments at the molecular level. Atmospheric moisture was considered to be a potential factor in impairing the adhesion performance of the primer, and thus, time- and humidity-dependent experiments were executed to monitor the molecular behavior at the primer surface using SFG. In addition, 180° peel testing experiments were conducted to measure the adhesion properties of primers after being exposed to the corresponding conditions to correlate to SFG results and establish a chemical structure-macroscopic performance relationship. This study on the changes at the primer surface in different environments with varied humidity levels as a function of time aims to provide an in-depth understanding of the moisture effect on isocyanate-based primers. These learnings may also be helpful toward exploring a broader range of coatings and surface layers and improving customer product use guidelines.
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Affiliation(s)
| | - Lorraine Hsu
- Coatings and Innovation Center, PPG, 4325 Rosanna Drive, Allison Park, Pennsylvania 15101, United States
| | - Amy Toolis
- Coatings and Innovation Center, PPG, 4325 Rosanna Drive, Allison Park, Pennsylvania 15101, United States
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36
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Guo W, Lu T, Gandhi Z, Chen Z. Probing Orientations and Conformations of Peptides and Proteins at Buried Interfaces. J Phys Chem Lett 2021; 12:10144-10155. [PMID: 34637311 DOI: 10.1021/acs.jpclett.1c02956] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molecular structures of peptides/proteins at interfaces determine their interfacial properties, which play important roles in many applications. It is difficult to probe interfacial peptide/protein structures because of the lack of appropriate tools. Sum frequency generation (SFG) vibrational spectroscopy has been developed into a powerful technique to elucidate molecular structures of peptides/proteins at buried solid/liquid and liquid/liquid interfaces. SFG has been successfully applied to study molecular interactions between model cell membranes and antimicrobial peptides/membrane proteins, surface-immobilized peptides/enzymes, and physically adsorbed peptides/proteins on polymers and 2D materials. A variety of other analytical techniques and computational simulations provide supporting information to SFG studies, leading to more complete understanding of structure-function relationships of interfacial peptides/proteins. With the advance of SFG techniques and data analysis methods, along with newly developed supplemental tools and simulation methodology, SFG research on interfacial peptides/proteins will further impact research in fields like chemistry, biology, biophysics, engineering, and beyond.
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Affiliation(s)
- Wen Guo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Tieyi Lu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zahra Gandhi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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37
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Analytical challenges of glycosaminoglycans at biological interfaces. Anal Bioanal Chem 2021; 414:85-93. [PMID: 34647134 PMCID: PMC8514262 DOI: 10.1007/s00216-021-03705-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 11/15/2022]
Abstract
The analysis of glycosaminoglycans (GAGs) is a challenging task due to their high structural heterogeneity, which results in diverse GAG chains with similar chemical properties. Simultaneously, it is of high importance to understand their role and behavior in biological systems. It has been known for decades now that GAGs can interact with lipid molecules and thus contribute to the onset of atherosclerosis, but their interactions at and with biological interfaces, such as the cell membrane, are yet to be revealed. Here, analytical approaches that could yield important knowledge on the GAG-cell membrane interactions as well as the synthetic and analytical advances that make their study possible are discussed. Due to recent developments in laser technology, we particularly focus on nonlinear spectroscopic methods, especially vibrational sum-frequency generation spectroscopy, which has the potential to unravel the structural complexity of heterogeneous biological interfaces in contact with GAGs, in situ and in real time.
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38
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Huang H, Zhang C, Crisci R, Lu T, Hung HC, Sajib MSJ, Sarker P, Ma J, Wei T, Jiang S, Chen Z. Strong Surface Hydration and Salt Resistant Mechanism of a New Nonfouling Zwitterionic Polymer Based on Protein Stabilizer TMAO. J Am Chem Soc 2021; 143:16786-16795. [PMID: 34582683 DOI: 10.1021/jacs.1c08280] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Zwitterionic polymers exhibit excellent nonfouling performance due to their strong surface hydrations. However, salt molecules may severely reduce the surface hydrations of typical zwitterionic polymers, making the application of these polymers in real biological and marine environments challenging. Recently, a new zwitterionic polymer brush based on the protein stabilizer trimethylamine N-oxide (TMAO) was developed as an outstanding nonfouling material. Using surface-sensitive sum frequency generation (SFG) vibrational spectroscopy, we investigated the surface hydration of TMAO polymer brushes (pTMAO) and the effects of salts and proteins on such surface hydration. It was discovered that exposure to highly concentrated salt solutions such as seawater only moderately reduced surface hydration. This superior resistance to salt effects compared to other zwitterionic polymers is due to the shorter distance between the positively and negatively charged groups, thus a smaller dipole in pTMAO and strong hydration around TMAO zwitterion. This results in strong bonding interactions between the O- in pTMAO and water, and weaker interaction between O- and metal cations due to the strong repulsion from the N+ and hydration water. Computer simulations at quantum and atomistic scales were performed to support SFG analyses. In addition to the salt effect, it was discovered that exposure to proteins in seawater exerted minimal influence on the pTMAO surface hydration, indicating complete exclusion of protein attachment. The excellent nonfouling performance of pTMAO originates from its extremely strong surface hydration that exhibits effective resistance to disruptions induced by salts and proteins.
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Affiliation(s)
| | | | | | | | - Hsiang-Chieh Hung
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Md Symon Jahan Sajib
- Department of Chemical Engineering, Howard University, Washington D.C. 20059, United States
| | - Pranab Sarker
- Department of Chemical Engineering, Howard University, Washington D.C. 20059, United States
| | - Jinrong Ma
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Tao Wei
- Department of Chemical Engineering, Howard University, Washington D.C. 20059, United States
| | - Shaoyi Jiang
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
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Moll CJ, Giubertoni G, van Buren L, Versluis J, Koenderink GH, Bakker HJ. Molecular Structure and Surface Accumulation Dynamics of Hyaluronan at the Water-Air Interface. Macromolecules 2021; 54:8655-8663. [PMID: 34602653 PMCID: PMC8482758 DOI: 10.1021/acs.macromol.1c00366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Indexed: 11/30/2022]
Abstract
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Hyaluronan is a biopolymer
that is essential for many biological
processes in the human body, like the regulation of tissue lubrication
and inflammatory responses. Here, we study the behavior of hyaluronan
at aqueous surfaces using heterodyne-detected vibrational sum-frequency
generation spectroscopy (HD-VSFG). Low-molecular-weight hyaluronan
(∼150 kDa) gradually covers the water–air interface
within hours, leading to a negatively charged surface and a reorientation
of interfacial water molecules. The rate of surface accumulation strongly
increases when the bulk concentration of low-molecular-weight hyaluronan
is increased. In contrast, high-molecular-weight hyaluronan (>1
MDa)
cannot be detected at the surface, even hours after the addition of
the polymer to the aqueous solution. The strong dependence on the
polymer molecular weight can be explained by entanglements of the
hyaluronan polymers. We also find that for low-molecular-weight hyaluronan
the migration kinetics of hyaluronan in aqueous media shows an anomalous
dependence on the pH of the solution, which can be explained from
the interplay of hydrogen bonding and electrostatic interactions of
hyaluronan polymers.
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Affiliation(s)
- Carolyn J Moll
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Giulia Giubertoni
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands.,Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lennard van Buren
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands.,Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jan Versluis
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Gijsje H Koenderink
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands.,Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Huib J Bakker
- Amolf, Science Park 104, 1098 XG Amsterdam, The Netherlands
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40
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Shi L, McMillan JR, Yu D, Chen X, Tucker CJ, Wasserman E, Mohler C, Chen Z. Effect of Surfactant Concentration and Hydrophobicity on the Ordering of Water at a Silica Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:10806-10817. [PMID: 34455791 DOI: 10.1021/acs.langmuir.1c01731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The performance of nonionic surfactants is mediated by the interfacial interactions at the solid-liquid interface. Here we applied sum frequency generation (SFG) vibrational spectroscopy to probe the molecular structure of the silica-nonionic surfactant solution interface in situ, supplemented by quartz crystal microbalance with dissipation monitoring (QCM-D) and molecular dynamics (MD) simulations. The combined studies elucidated the effects of nonionic surfactant solution concentration, surfactant composition, and rinsing on the silica-surfactant solution interfacial structure. The nonionic surfactants studied include ethylene-oxide (EO) and butylene oxide (BO) components with different ratios. It was found that the CH groups of the surfactants at the silica-surfactant solution interfaces are disordered, but the interfacial water molecules are ordered, generating strong SFG OH signals. Solutions with higher concentrations of surfactant lead to a slightly higher amount of adsorbed surfactant at the silica interface, resulting in more water molecules being ordered at the interface, or a higher ordering of water molecules at the interface, or both. MD simulation results indicated that the nonionic surface molecules preferentially adsorb onto silanol sites on silica. A surfactant with a higher EO/BO ratio leads to more water molecules being ordered and a higher degree of ordering of water molecules at the silica-surfactant solution interface, exhibiting stronger SFG OH signal, although less material is adsorbed according to the QCM-D data. A thin layer of surfactants remained on the silica surface after multiple water rinses. To the best of our knowledge, this is the first time the combined approaches of SFG, QCM-D and MD simulation techniques have been applied to study nonionic surfactants at the silica-solution interface, which enhances our understanding on the interfacial interactions between nonionic surfactants, water and silica. The knowledge obtained from this study can be helpful to design the optimal surfactant concentration and composition for future applications.
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Affiliation(s)
- Lirong Shi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Janet R McMillan
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Decai Yu
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Xiaoyun Chen
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | | | - Eric Wasserman
- Dow Home & Personal Care, The Dow Chemical Company, Collegeville, Pennsylvania 19426, United States
| | - Carol Mohler
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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41
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Relaxation behavior of polymer thin films: Effects of free surface, buried interface, and geometrical confinement. Prog Polym Sci 2021. [DOI: 10.1016/j.progpolymsci.2021.101431] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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42
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Maekawa H, Kumar SKK, Mukherjee SS, Ge NH. Phase-Sensitive Vibrationally Resonant Sum-Frequency Generation Microscopy in Multiplex Configuration at 80 MHz Repetition Rate. J Phys Chem B 2021; 125:9507-9516. [PMID: 34433279 DOI: 10.1021/acs.jpcb.1c05430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vibrationally resonant sum-frequency generation (VR SFG) microscopy is an advanced imaging technique that can map out the intensity contrast of infrared and Raman active vibrational modes with micron to submicron lateral resolution. To broaden its applications and to obtain a molecular level of understanding, further technical advancement is needed to enable high-speed measurements of VR SFG microspectra at every pixel. In this study, we demonstrate a new VR SFG hyperspectral imaging platform combined with an ultrafast laser system operated at a repetition rate of 80 MHz. The multiplex configuration with broadband mid-infrared pulses makes it possible to measure a single microspectrum of CH/CH2 stretching modes in biological samples, such as starch granules and type I collagen tissue, with an exposure time of hundreds of milliseconds. Switching from the homodyne- to heterodyne-detected VR SFG hyperspectral imaging can be achieved by inserting a pair of optics into the beam path for local oscillator generation and delay time adjustment, which enables self-phase-stabilized spectral interferometry. We investigate the relationship between phase images of several different C-H modes and the relative orientation of collagen triple-helix in fibril bundles. The results show that the new multiplex VR SFG microscope operated at a high repetition rate is a powerful approach to probe the structural features and spatial arrangements of biological systems in detail.
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Affiliation(s)
- Hiroaki Maekawa
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025, United States
| | - S K Karthick Kumar
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025, United States
| | - Sudipta S Mukherjee
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025, United States
| | - Nien-Hui Ge
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025, United States
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43
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Geddes HS, Hutchinson HD, Ha AR, Funnell NP, Goodwin AL. Extracting interface correlations from the pair distribution function of composite materials. NANOSCALE 2021; 13:13220-13224. [PMID: 34477729 PMCID: PMC8359142 DOI: 10.1039/d1nr01922h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/23/2021] [Indexed: 05/31/2023]
Abstract
Using a non-negative matrix factorisation (NMF) approach, we show how the pair distribution function (PDF) of complex mixtures can be deconvolved into the contributions from the individual phase components and also the interface between phases. Our focus is on the model system Fe∥Fe3O4. We establish proof-of-concept using idealised PDF data generated from established theory-driven models of the Fe∥Fe3O4 interface. Using X-ray total scattering measurements for corroded Fe samples, and employing our newly-developed NMF analysis, we extract the experimental interface PDF ('iPDF') for this same system. We find excellent agreement between theory and experiment. The implications of our results in the broader context of interface characterisation for complex functional materials are discussed.
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Affiliation(s)
- Harry S. Geddes
- Inorganic Chemistry Laboratory, Department of Chemistry, University of OxfordSouth Parks RoadOxfordOX1 3QRUK
| | - Henry D. Hutchinson
- Inorganic Chemistry Laboratory, Department of Chemistry, University of OxfordSouth Parks RoadOxfordOX1 3QRUK
| | - Alex R. Ha
- Inorganic Chemistry Laboratory, Department of Chemistry, University of OxfordSouth Parks RoadOxfordOX1 3QRUK
| | - Nicholas P. Funnell
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Science and Innovation CampusDidcotOX11 0QXUK
| | - Andrew L. Goodwin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of OxfordSouth Parks RoadOxfordOX1 3QRUK
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44
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Guo W, Zou X, Jiang H, Koebke KJ, Hoarau M, Crisci R, Lu T, Wei T, Marsh ENG, Chen Z. Molecular Structure of the Surface-Immobilized Super Uranyl Binding Protein. J Phys Chem B 2021; 125:7706-7716. [PMID: 34254804 DOI: 10.1021/acs.jpcb.1c03849] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recently, a super uranyl binding protein (SUP) was developed, which exhibits excellent sensitivity/selectivity to bind uranyl ions. It can be immobilized onto a surface in sensing devices to detect uranyl ions. Here, sum frequency generation (SFG) vibrational spectroscopy was applied to probe the interfacial structures of surface-immobilized SUP. The collected SFG spectra were compared to the calculated orientation-dependent SUP SFG spectra using a one-excitonic Hamiltonian approach based on the SUP crystal structures to deduce the most likely surface-immobilized SUP orientation(s). Furthermore, discrete molecular dynamics (DMD) simulation was applied to refine the surface-immobilized SUP conformations and orientations. The immobilized SUP structures calculated from DMD simulations confirmed the SUP orientations obtained from SFG data analyzed based on the crystal structures and were then used for a new round of SFG orientation analysis to more accurately determine the interfacial orientations and conformations of immobilized SUP before and after uranyl ion binding, providing an in-depth understanding of molecular interactions between SUP and the surface and the effect of uranyl ion binding on the SUP interfacial structures. We believe that the developed method of combining SFG measurements, DMD simulation, and Hamiltonian data analysis approach is widely applicable to study biomolecules at solid/liquid interfaces.
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Affiliation(s)
- Wen Guo
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Xingquan Zou
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Hanjie Jiang
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Karl J Koebke
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Marie Hoarau
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Ralph Crisci
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Tieyi Lu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Tao Wei
- Department of Chemical Engineering, Howard University, 2366 Sixth Street, NW, Washington, D.C. 20059, United States
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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45
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Cotton DE, Roberts ST. Sensitivity of sum frequency generation experimental conditions to thin film interference effects. J Chem Phys 2021; 154:114704. [PMID: 33752341 DOI: 10.1063/5.0039897] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sum-frequency generation (SFG) spectroscopy has furthered our understanding of the chemical interfaces that guide key processes in biology, catalysis, environmental science, and energy conversion. However, interpreting SFG spectra of systems containing several internal interfaces, such as thin film electronics, electrochemical cells, and biofilms, is challenging as different interfaces within these structures can produce interfering SFG signals. One potential way to address this issue is to carefully select experimental conditions that amplify the SFG signal of an interface of interest over all others. In this report, we investigate a model two-interface system to assess our ability to isolate the SFG signal from each interface. For SFG experiments performed in a reflective geometry, we find that there are few experimental conditions under which the SFG signal originating from either interface can be amplified and isolated from the other. However, by performing several measurements under conditions that alter their interference, we find that we can reconstruct each signal even in cases where the SFG signal from one interface is more than an order of magnitude smaller than its counterpart. The number of spectra needed for this reconstruction varies depending on the signal-to-noise level of the SFG dataset and the degree to which different experiments in a dataset vary in their sensitivity to each interface. Taken together, our work provides general guidelines for designing experimental protocols that can isolate SFG signals stemming from a particular region of interest within complex samples.
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Affiliation(s)
- Daniel E Cotton
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Sean T Roberts
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
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46
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Lin T, Wu Y, Santos E, Chen X, Ahn D, Mohler C, Chen Z. Molecular Insights into Adhesion at a Buried Silica-Filled Silicone/Polyethylene Terephthalate Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15128-15140. [PMID: 33283520 DOI: 10.1021/acs.langmuir.0c02719] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Silicone adhesives are widely used in many important applications in aviation, automotive, construction, and electronics industries. The mixture of (3-glycidoxypropyl)trimethoxysilane (γ-GPS) and hydroxy-terminated dimethyl methylvinyl co-siloxanol (DMMVS) has been widely used as an adhesion promoter in silicone elastomers to enhance the adhesion between silicone and other materials including polymers. The interfacial molecular structures of silicone elastomers and the adhesion promotion mechanisms of a γ-GPS-DMMVS mixture in silicone without a filler or an adhesion catalyst (AC) have been extensively investigated using sum frequency generation (SFG) vibrational spectroscopy previously. In this research, SFG was applied to study interfacial structures of silicone elastomeric adhesives in the presence of a silica filler and/or a zirconium(IV) acetylacetonate adhesion catalyst at the silicone/polyethylene terephthalate (PET) interface in situ nondestructively to understand their individual and synergy effects. The interfacial structures obtained from the SFG study were correlated to the adhesion behavior to PET. The interfacial reactions of methoxy and epoxy groups of the adhesion promoter were found to play significant roles in enhancing the interfacial adhesion of the buried interface. This research provides an in-depth molecular-level understanding on the effects of a filler and an adhesion catalyst on the interfacial behavior of the adhesion promotion system for silicone elastomers as well as the related impact on adhesion.
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Affiliation(s)
- Ting Lin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yuchen Wu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Elizabeth Santos
- Dow Performance Silicones, Auburn, Michigan 48611, United States
| | - Xiaoyun Chen
- Core R&D, Dow Chemical, Midland, Michigan 48674, United States
| | - Dongchan Ahn
- Dow Performance Silicones, Auburn, Michigan 48611, United States
| | - Carol Mohler
- Core R&D, Dow Chemical, Midland, Michigan 48674, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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47
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Abstract
The basic theory of sum-frequency generation (SFG) is revisited. A rigorous derivation showing that linear optical transmission and reflection at an interface result from the interference of the incident wave and induced radiation wave in a medium is presented. The derivation is extended to SFG in a medium with a finite interface layer to see how SFG evolves. Detailed description on interface vs bulk and electric dipole (ED) vs electric quadrupole (EQ) contribution to SFG are provided with essentially no model dependence, putting the theory of SFG on a solid ground and removing possible existing confusions. Electric-quadrupole contributions to SFG from the interface and bulk are discussed. It is seen that there is a relevant bulk EQ contribution intrinsically inseparable in measurement from the interface ED contribution but plays a major role among all EQ contributions; its importance relative to the ED part can only be judged by referring to the established reference cases.
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Affiliation(s)
- Y R Shen
- Physics Department, University of California, Berkeley, California 94707, USA and Physics Department, Fudan University, Shanghai, China
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48
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Mori W, Wang L, Sato Y, Morita A. Development of quadrupole susceptibility automatic calculator in sum frequency generation spectroscopy and application to methyl C-H vibrations. J Chem Phys 2020; 153:174705. [PMID: 33167643 DOI: 10.1063/5.0026341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sum frequency generation (SFG) spectroscopy has been established as a powerful interface probe technique based on the electric dipole approximation, while possible signals of quadrupole and bulk origin have also been known for a long time. In this work, we developed a computational tool, namely, Qsac (quadrupole susceptibility automatic calculator), to evaluate the comprehensive contributions of the dipole/quadrupole and interface/bulk in the arbitrary vibrational bands of SFG spectra. The calculations of relevant susceptibility terms are performed on the basis of the theory of energy representation using quantum chemical calculation and molecular dynamics simulation, which allows for semi-quantitative comparison among these terms on the same footing. We applied the Qsac to the methyl C-H stretching bands of organic molecules and found a general trend that the weak asymmetric bands are more sensitive to the bulk contribution than the symmetric ones. The phases of interface and bulk terms tend to cancel in the asymmetric band, which results in the reduced band intensity in the SFG spectra.
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Affiliation(s)
- Wataru Mori
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Lin Wang
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Yamato Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Akihiro Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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49
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Zhang S, Andre JS, Hsu L, Toolis A, Esarey SL, Li B, Chen Z. Nondestructive In Situ Detection of Chemical Reactions at the Buried Interface between Polyurethane and Isocyanate-Based Primer. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01862] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Shuqing Zhang
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - John S Andre
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Lorraine Hsu
- Coatings and Innovation Center, PPG, 4325 Rosanna Drive, Allison Park, Pennsylvania 15101, United States
| | - Amy Toolis
- Coatings and Innovation Center, PPG, 4325 Rosanna Drive, Allison Park, Pennsylvania 15101, United States
| | - Samuel L Esarey
- Coatings and Innovation Center, PPG, 4325 Rosanna Drive, Allison Park, Pennsylvania 15101, United States
| | - Bolin Li
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Department of Macromolecular Science and Engineering, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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50
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Guo W, Xu S, Reichart TM, Xiao M, Lu T, Mello C, Chen Z. Probing Molecular Interactions between Surface-Immobilized Antimicrobial Peptides and Lipopolysaccharides In Situ. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12383-12393. [PMID: 33034460 DOI: 10.1021/acs.langmuir.0c02492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria. Recently, a label-free immobilized antimicrobial peptide (AMP) surface plasmon resonance platform was developed to successfully distinguish LPS from multiple bacterial strains. Among the tested AMPs, SMAP29 exhibited excellent affinity with LPS and has two independent LPS-binding sites located at two termini of the peptide. In this study, sum frequency generation vibrational spectroscopy was applied to investigate molecular interactions between three LPS samples and surface-immobilized SMAP29 via the N-terminus, the C-terminus, and a middle site at the solid/liquid interface in situ in real-time, supplemented by circular dichroism spectroscopy. It was found that the conformations and orientations of surface-immobilized SMAP29 via different sites are different when interacting with the same LPS, with different interaction kinetics. The same SMAP29 sample also has different structures and interaction kinetics while interacting with different LPS samples with different charge densities and hydrophobicities. The observed results on molecular interactions between surface-immobilized peptides and LPS can well interpret the different adsorption amounts of various LPSs on different surface-immobilized peptides.
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Affiliation(s)
- Wen Guo
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Shan Xu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Timothy M Reichart
- Office of the Chief Scientist, Combat Capabilities Development Command Soldier Center, 15 Kansas Street, Natick, Massachusetts 01760, United States
- Department of Chemistry, Hampden-Sydney College, Hampden-Sydney, VA 23943, United States
| | - Minyu Xiao
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Tieyi Lu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Charlene Mello
- Office of the Chief Scientist, Combat Capabilities Development Command Soldier Center, 15 Kansas Street, Natick, Massachusetts 01760, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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