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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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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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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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4
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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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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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Inutsuka M, Watanabe H, Aoyagi M, Yamada NL, Tanaka C, Ikehara T, Kawaguchi D, Yamamoto S, Tanaka K. Effect of Oligomer Segregation on the Aggregation State and Strength at the Polystyrene/Substrate Interface. ACS Macro Lett 2022; 11:504-509. [PMID: 35575338 DOI: 10.1021/acsmacrolett.2c00062] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interfacial strength of polystyrene (PS) with and without PS oligomers in contact with a glass substrate was examined to determine the relationship between the interfacial aggregation state and adhesion. The shear bond strength and adsorbed layer thickness of neat PS exhibited a similar dependence on the thermal annealing time: they increased to constant values within almost the same time. This implies that the adhesion of the polymer is closely related to the formation of an adsorbed layer at the adhesion interface. Nevertheless, in the case of PS with a small amount of oligomer, the shear bond strength decreased, while the adsorbed layer thickness was almost the same as that of neat PS. Based on the results of interfacial analyses, we propose that the interfacial segregation of the oligomer reduced the entanglement between the interfacial free chains in the adsorbed layer and the bulk chains.
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Affiliation(s)
- Manabu Inutsuka
- Organic Materials Diagnosis Group, National Institute of Advanced Industrial Science and Technology, 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Hirohmi Watanabe
- Organic Materials Diagnosis Group, National Institute of Advanced Industrial Science and Technology, 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Masaru Aoyagi
- Organic Materials Diagnosis Group, National Institute of Advanced Industrial Science and Technology, 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Norifumi L. Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Chisa Tanaka
- Department of Material and Life Chemistry, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama-shi, Kanagawa 221-8686, Japan
| | - Takayuki Ikehara
- Department of Material and Life Chemistry, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama-shi, Kanagawa 221-8686, Japan
| | - Daisuke Kawaguchi
- Department of Applied Chemistry, Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Satoru Yamamoto
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry, Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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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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de Lima BM, Hayes PL, Wood-Adams PM. Influence of Polymer Molecular Weight on Chain Conformation at the Polystyrene/Silver Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:10036-10045. [PMID: 34379428 DOI: 10.1021/acs.langmuir.1c01211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The dependence between the conformation of polystyrene (PS) and its molecular weight (Mw) in the vicinity of a metal interface was investigated by sum frequency generation (SFG) spectroscopy. Tilt angles θ ≥ 50° (the angle between the C2 axis of the pendant phenyl ring and the surface normal) were observed for all samples because of the interaction between the aromatic rings and the metal surface. Furthermore, it was found that θ decreases with increasing Mw for PS samples ranging from 20 × 103 g/mol to 400 × 103 g/mol. The intensity of the backbone SFG signal was higher for high Mw PS, compared to low Mw PS, indicating a greater number of backbone interactions with the silver substrate surface for the high Mw sample. These structural differences are driven by different entropic and enthalpic contributions to the free energy of adsorption for different polymer molecular weights. Differences in the polymer free volume and in the relative amount of chain ends with higher mobility may also influence the chain conformation. These results suggest that important interfacial properties of polymeric thin films, such as adhesion and wettability, could be tailored by modifying the polymer Mw to achieve the desired interfacial conformation.
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Affiliation(s)
- Bianca M de Lima
- Department of Chemical and Materials Engineering, Concordia University, 1435 Rue Guy, S- GM 900-13, Montréal, Québec H3H 2L5, Canada
| | - Patrick L Hayes
- Department of Chemistry, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V 0B3, Canada
| | - Paula M Wood-Adams
- Department of Chemical and Materials Engineering, Concordia University, 1435 Rue Guy, S- GM 900-13, Montréal, Québec H3H 2L5, Canada
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Xu W, Mihhels K, Kotov N, Lepikko S, Ras RHA, Johnson CM, Pettersson T, Kontturi E. Solid-state polymer adsorption for surface modification: The role of molecular weight. J Colloid Interface Sci 2021; 605:441-450. [PMID: 34333417 DOI: 10.1016/j.jcis.2021.07.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/11/2021] [Accepted: 07/12/2021] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Solid-state polymer adsorption offers a distinct approach for surface modification. These ultrathin, so-called Guiselin layers can easily be obtained by placing a polymer melt in contact with an interface, followed by a removal of the non-adsorbed layer with a good solvent. While the mechanism of formation has been well established for Guiselin layers, their stability, crucial from the perspective of materials applications, is not. The stability is a trade-off in the entropic penalty between cooperative detachment of the number of segments directly adsorbed on the substrate and consecutively pinned monomers. EXPERIMENTS Experimental model systems of Guiselin layers of polystyrene (PS) on silicon wafers with native oxide layer on top were employed. The stability of the adsorbed layers was studied as a function of PS molecular weight and polydispersibility by various microscopic and spectroscopic tools as well as quasi-static contact angle measurements. FINDINGS Adsorbed layers from low molecular weight PS were disrupted with typical spinodal decomposition patterns whereas high molecular weight (>500 kDa) PS resulted in stable, continuous layers. Moreover, we show that Guiselin layers offer an enticing way to modify a surface, as demonstrated by adsorbed PS that imparts a hydrophobic character to initially hydrophilic silicon wafers.
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Affiliation(s)
- Wenyang Xu
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland; Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden.
| | - Karl Mihhels
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Nikolay Kotov
- Department of Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Sakari Lepikko
- Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
| | - Robin H A Ras
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland; Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
| | - C Magnus Johnson
- Department of Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Torbjörn Pettersson
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden; Wallenberg Wood Science Centre, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden.
| | - Eero Kontturi
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland.
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Guo R, Li B, Lu T, Lin T, Andre J, Zhang C, Zhi L, Chen Z. Molecular Orientations at Buried Conducting Polymer/Graphene Interfaces. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ruiying Guo
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100039, China
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Bolin Li
- 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
| | - Ting Lin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John Andre
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Chengcheng Zhang
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Linjie Zhi
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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11
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Andre JS, Li B, Chen X, Paradkar R, Walther B, Feng C, Tucker C, Mohler C, Chen Z. Interfacial reaction of a maleic anhydride grafted polyolefin with ethylene vinyl alcohol copolymer at the buried solid/solid interface. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123141] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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12
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Oda Y, Kawaguchi D, Morimitsu Y, Yamamoto S, Tanaka K. Direct observation of morphological transition for an adsorbed single polymer chain. Sci Rep 2020; 10:20914. [PMID: 33262397 PMCID: PMC7708982 DOI: 10.1038/s41598-020-77761-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/06/2020] [Indexed: 11/09/2022] Open
Abstract
A better understanding of the structure of polymers at solid interfaces is crucial for designing various polymer nano-composite materials from structural materials to nanomaterials for use in industry. To this end, the first step is to obtain information on how synthetic polymer chains adsorb onto a solid surface. We closely followed the trajectory of a single polymer chain on the surface as a function of temperature using atomic force microscopy. Combining the results with a full-atomistic molecular dynamics simulation revealed that the chain became more rigid on the way to reaching a pseudo-equilibrium state, accompanied by a change in its local conformation from mainly loops to trains. This information will be useful for regulating the physical properties of polymers at the interface.
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Affiliation(s)
- Yukari Oda
- Department of Applied Chemistry, Kyushu University, Fukuoka, 819-0395, Japan
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka, 819-0395, Japan
| | - Daisuke Kawaguchi
- Department of Applied Chemistry, Kyushu University, Fukuoka, 819-0395, Japan
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka, 819-0395, Japan
| | - Yuma Morimitsu
- Department of Applied Chemistry, Kyushu University, Fukuoka, 819-0395, Japan
| | - Satoru Yamamoto
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka, 819-0395, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry, Kyushu University, Fukuoka, 819-0395, Japan.
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka, 819-0395, Japan.
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan.
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13
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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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Thees MF, McGuire JA, Roth CB. Review and reproducibility of forming adsorbed layers from solvent washing of melt annealed films. SOFT MATTER 2020; 16:5366-5387. [PMID: 32365149 DOI: 10.1039/d0sm00565g] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent studies suggest chain adsorption in the melt may be responsible for a number of property changes in thin films by making correlations between the residual adsorbed layer thickness hads(t) measured after a given solvent washing procedure as a function of annealing time t of the film at an elevated temperature prior to this solvent rinse. This procedure, frequently called "Guiselin's experiment", refers to the thought experiment proposed in a 1992 theoretical treatment by Guiselin that assumed chain segments in contact with the surface are irreversibly adsorbed whereby unadsorbed chains could be washed away by solvent without disturbing the adsorbed substrate contact points in the melt. In the present work, we review this recent literature, identifying and experimentally testing a common protocol for forming adsorbed layers hads(t) from solvent washing melt films. We find hads(t) curves to be far less reproducible and reliable than implied in the literature, strongly dependent on solvent washing and substrate cleaning conditions, and annealing at elevated temperatures is unnecessary as densification of films sitting at room temperature makes the glassy film harder to wash off, leaving behind hads of comparable thickness. This review also summarizes literature understanding developed over several decades of study on polymer adsorption in solution, which experimentally demonstrated that polymer chains in solution are highly mobile, diffusing and exchanging on the surface even in the limit of strong adsorption, contradicting Guiselin's assumption. Preformed adsorbed layers of different thicknesses hads are shown to not affect the average glass transition temperature or physical aging of 30 nm thick films. In summary, a number of open questions and implications are discussed related to thin films and polymer nanocomposites.
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Affiliation(s)
- Michael F Thees
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA.
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Zhang F, Li X, Ma Y, Wang C, Hu P, Wang F, Lu X. Illustrating Interfacial Interaction between Honey Bee Venom Phospholipase A 2 and Supported Negatively Charged Lipids with Sum Frequency Generation and Laser Scanning Confocal Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2946-2953. [PMID: 32093479 DOI: 10.1021/acs.langmuir.0c00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phospholipase A2 is an important enzyme species which can widely be found in animals, plants, bacteria, and so on. A large number of studies have shown that phospholipase A2 is highly catalytic toward the lipids. Here, sum frequency generation (SFG) vibrational spectroscopy and laser scanning confocal microscopy (LSCM) were applied to study the interaction between honey bee venom phospholipase A2 (bvPLA2) and the negatively charged DPPG bilayer. In both cases without and with the calcium ions (Ca2+), the bvPLA2 molecules were adsorbed onto the outer leaflet surface with the orientational order, and the adsorbed bvPLA2 molecules damaged the order of the packed outer leaflet. In comparison to the case without Ca2+, the addition of Ca2+ can accelerate the attaching process of bvPLA2 to the outer leaflet surface and decelerate the process of damaging the outer leaflet order. The experimental result also confirmed, with the help of the Ca2+, the DPPG molecules in the outer leaflet were hydrolyzed, with both hydrolysates, that is, lysophospholipids and fatty acids, remaining at the interface, showing a distinct difference from previous published literatures regarding neutral lipids [Phys. Chem. Chem. Phys. 2018, 20, 63-67] and PLA1 [Langmuir 2019, 35, 12831-12838].
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Affiliation(s)
- Furong Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xu Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yonghao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chu Wang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Pengcheng Hu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Feng Wang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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