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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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2
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Polymer-solvent interaction and conformational changes at a molecular level: Implication to solvent-assisted deformation and aggregation at the polymer surface. J Colloid Interface Sci 2022; 616:221-233. [DOI: 10.1016/j.jcis.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 11/17/2022]
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3
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Luo Y, Wang C, Pang AP, Zhang X, Wang D, Lu X. Low-Concentration Salt Solution Changes the Interfacial Molecular Behavior of Polyelectrolyte Brushes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yongsheng Luo
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Chu Wang
- 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
| | - Xiang Zhang
- National Center for International Joint Research of Micro−Nano Molding Technology, School of Mechanics & Engineering Science, Zhengzhou University, Zhengzhou 450001, 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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4
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Cota R, Tiwari A, Ensing B, Bakker HJ, Woutersen S. Hydration interactions beyond the first solvation shell in aqueous phenolate solution. Phys Chem Chem Phys 2020; 22:19940-19947. [DOI: 10.1039/d0cp01209b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the orientational dynamics of water molecules solvating phenolate ions using ultrafast vibrational spectroscopy and density functional theory-based molecular dynamics simulations.
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Affiliation(s)
- Roberto Cota
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
- AMOLF
| | - Ambuj Tiwari
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
| | - Bernd Ensing
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
| | | | - Sander Woutersen
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
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5
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Zuo B, Li C, Li Y, Qian W, Ye X, Zhang L, Wang X. Toward Achieving Highly Ordered Fluorinated Surfaces of Spin-Coated Polymer Thin Films by Optimizing the Air/Liquid Interfacial Structure of the Casting Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3993-4003. [PMID: 29505264 DOI: 10.1021/acs.langmuir.8b00309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thin polymer films with well-assembled fluorinated groups on their surfaces are not easily achieved via spin-coating film-fabrication methods because the solution solidifies very rapidly during spin-coating, which hinders the fluorinated moieties from segregating and organizing on the film surface. In this contribution, we have proposed a comprehensive strategy toward achieving well-ordered fluorinated thin films surfaces by optimizing the molecular organization at air/liquid interface of the film-formation solutions. To validate such a route, poly(methyl methacrylate) (PMMA) end-capped with several 2-perfluorooctylethyl methacrylate (FMA) units was employed as the model polymer for investigations. The air/solution interfacial structures were optimized by systematically changing the polymer chain structures and properties of the casting solvents. It was found that the polymers that form loosely associated aggregates (e.g., FMA1- ec-PMMA65- ec-FMA1) and a solvent with better solubility to FMA while having not too low surface tension (i.e., toluene) can combine to produce solutions with well-assembled FMA at the interfaces. By spin-coating the solutions with well-organized interfaces, an ultrathin film with perfluorinated groups that were highly oriented toward the film surface was readily achieved, exhibiting surface energies as low as 7.2 mJ/m2, which is among the lowest reported so far for the spin-coated thin films, and a very high F/C ratio (i.e., 0.98).
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Cheng Li
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Yawei Li
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Wenhao Qian
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Xiuyun Ye
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Li Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry , Zhejiang Sci-Tech University , Hangzhou 310018 , China
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6
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Zhang C. Sum Frequency Generation Vibrational Spectroscopy for Characterization of Buried Polymer Interfaces. APPLIED SPECTROSCOPY 2017; 71:1717-1749. [PMID: 28537432 DOI: 10.1177/0003702817708321] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Sum frequency generation vibrational spectroscopy (SFG-VS) has become one of the most appealing technologies to characterize molecular structures at interfaces. In this focal point review, we focus on SFG-VS studies at buried polymer interfaces and review many of the recent publications in the field. We also cover the essential theoretical background of SFG-VS and discuss the experimental implementation of SFG-VS.
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Affiliation(s)
- Chi Zhang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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7
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Lu X, Zhang C, Ulrich N, Xiao M, Ma YH, Chen Z. Studying Polymer Surfaces and Interfaces with Sum Frequency Generation Vibrational Spectroscopy. Anal Chem 2016; 89:466-489. [DOI: 10.1021/acs.analchem.6b04320] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xiaolin Lu
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Chi Zhang
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Nathan Ulrich
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Minyu Xiao
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Yong-Hao Ma
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Zhan Chen
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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8
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Li X, Li B, Zhang X, Li C, Guo Z, Zhou D, Lu X. Detecting Surface Hydration of Poly(2-hydroxyethyl methacrylate) in Solution in situ. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00389] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Xu Li
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province P. R. China
| | - Bolin Li
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province P. R. China
| | - Xiaodong Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province P. R. China
| | - Chengcheng Li
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province P. R. China
| | - Zhirui Guo
- Department
of Geriatrics, Second Affiliated Hospital of Nanjing Medical University, Nanjing 210029, P. R. China
| | - Dongshan Zhou
- Department
of Polymer Science and Engineering, School of Chemistry and Chemical
Engineering, State Key Laboratory of Coordination Chemistry, Nanjing
National Laboratory of Microstructure, Nanjing University, Nanjing 210093, 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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9
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Kearns PM, O'Brien DB, Massari AM. Optical Interference Enhances Nonlinear Spectroscopic Sensitivity: When Light Gives You Lemons, Model Lemonade. J Phys Chem Lett 2016; 7:62-68. [PMID: 26654548 DOI: 10.1021/acs.jpclett.5b01958] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Optical interference effects can be a nuisance in spectroscopy, especially in nonlinear experiments in which multiple incoming and outgoing beams are present. Vibrational sum frequency generation is particularly susceptible to interference effects because it is often applied to planar, layered materials, driving many of its practitioners to great lengths to avoid signal generation from multiple interfaces. In this perspective, we take a positive view of this metaphorical "lemon" and demonstrate how optical interference can be used as a tool to extract subtle changes in interfacial vibrational spectra. Specifically, we use small frequency shifts at a buried interface in an organic field-effect transistor to determine the fractional charge per molecule during device operation. The transfer matrix approach to nonlinear signal modeling is general and readily applied to complex layered samples that are increasingly popular in modern studies. More importantly, we show that a failure to consider interference effects can lead to erroneous interpretations of nonlinear data.
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Affiliation(s)
- Patrick M Kearns
- Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Daniel B O'Brien
- Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Aaron M Massari
- Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
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10
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Morsch S, Lyon S, Greensmith P, Smith SD, Gibbon SR. Mapping water uptake in organic coatings using AFM-IR. Faraday Discuss 2015; 180:527-42. [PMID: 25905798 DOI: 10.1039/c4fd00229f] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The long-term failure of seemingly intact corrosion resistant organic coatings is thought to occur via the development of ionic transport channels, which spontaneously evolve from hydrophilic regions on immersion, i.e., as a result of localized water uptake. To this end, we investigate water uptake characteristics for industrial epoxy-phenolic can coatings after immersion in deionized water and drying. Moisture sorption and the changing nature of polymer-water interactions are assessed using FTIR for dry and pre-soaked films. More water is found to be absorbed by the pre-soaked coatings on exposure to a humid environment, with a greater degree of hydrogen-bonding between the polymer and water. Furthermore, morphological changes are then correlated to localized water uptake using the AFM-IR technique. Nanoscale softened regions develop on soaking, and these are found to absorb a greater proportion of water from a humid environment.
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Affiliation(s)
- S Morsch
- Corrosion and Protection Centre, School of Materials, The University of Manchester, The Mill, Sackville St, Manchester, M13 9PL, UK.
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11
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Ulrich NW, Myers JN, Chen Z. Characterization of polymer/epoxy buried interfaces with silane adhesion promoters before and after hygrothermal aging for the elucidation of molecular level details relevant to adhesion. RSC Adv 2015. [DOI: 10.1039/c5ra24332g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Buried interfacial structures containing epoxy underfills are incredibly important in the microelectronics industry and their structures determine the interfacial adhesion properties and ultimately their lifetime.
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Affiliation(s)
| | - John N. Myers
- Department of Chemistry
- University of Michigan
- Ann Arbor
- USA
| | - Zhan Chen
- Department of Chemistry
- University of Michigan
- Ann Arbor
- USA
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12
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Zhang X, Myers JN, Lin Q, Bielefeld JD, Chen Z. Probing the molecular structures of plasma-damaged and surface-repaired low-k dielectrics. Phys Chem Chem Phys 2015; 17:26130-9. [DOI: 10.1039/c5cp03649f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A comprehensive characterization on the plasma-damaged and silylation-repaired low-k dielectrics was demonstrated here at the molecular level.
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Affiliation(s)
- Xiaoxian Zhang
- Department of Chemistry
- University of Michigan
- Ann Arbor
- USA
| | - John N. Myers
- Department of Chemistry
- University of Michigan
- Ann Arbor
- USA
| | | | | | - Zhan Chen
- Department of Chemistry
- University of Michigan
- Ann Arbor
- USA
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13
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Myers JN, Zhang C, Lee KW, Williamson J, Chen Z. Hygrothermal aging effects on buried molecular structures at epoxy interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:165-171. [PMID: 24345068 DOI: 10.1021/la4037869] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interfacial properties such as adhesion are determined by interfacial molecular structures. Adhesive interfaces in microelectronic packages that include organic polymers such as epoxy are susceptible to delamination during accelerated stress testing. Infrared-visible sum frequency generation vibrational spectroscopy (SFG) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used to study molecular structures at buried epoxy interfaces during hygrothermal aging to relate molecular structural changes at buried interfaces to decreases in macroscopic adhesion strength. SFG peaks associated with strongly hydrogen bonded water were detected at hydrophilic epoxy interfaces. Ordered interfacial water was also correlated to large decreases in interfacial adhesion strength that occurred as a result of hygrothermal aging, which suggests that water diffused to the interface and replaced original hydrogen bond networks. No water peaks were observed at hydrophobic epoxy interfaces, which was correlated with a much smaller decrease in adhesion strength from the same aging process. ATR-FTIR water signals observed in the epoxy bulk were mainly contributed by relatively weakly hydrogen bonded water molecules, which suggests that the bulk and interfacial water structure was different. Changes in interfacial methyl structures were observed regardless of the interfacial hydrophobicity which could be due to water acting as a plasticizer that restructured both the bulk and interfacial molecular structure. This research demonstrates that SFG studies of molecular structural changes at buried epoxy interfaces during hygrothermal aging can contribute to the understanding of moisture-induced failure mechanisms in electronic packages that contain organic adhesives.
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Affiliation(s)
- John N Myers
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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14
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Li B, Zhou J, Xu X, Yu J, Shao W, Fang Y, Lu X. Solvent quality affects chain conformational order at the polymer surface revealed by sum frequency generation vibrational spectroscopy. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Zhang C, Myers J, Chen Z. Elucidation of molecular structures at buried polymer interfaces and biological interfaces using sum frequency generation vibrational spectroscopy. SOFT MATTER 2013; 9:4738-4761. [PMID: 23710244 PMCID: PMC3661304 DOI: 10.1039/c3sm27710k] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been developed into an important technique to study surfaces and interfaces. It can probe buried interfaces in situ and provide molecular level structural information such as the presence of various chemical moieties, quantitative molecular functional group orientation, and time dependent kinetics or dynamics at such interfaces. This paper focuses on these three most important advantages of SFG and reviews some of the recent progress in SFG studies on interfaces related to polymer materials and biomolecules. The results discussed here demonstrate that SFG can provide important molecular structural information of buried interfaces in situ and in real time, which is difficult to obtain by other surface sensitive analytical techniques.
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Affiliation(s)
- Chi Zhang
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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16
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Hankett JM, Liu Y, Zhang X, Zhang C, Chen Z. Molecular level studies of polymer behaviors at the water interface using sum frequency generation vibrational spectroscopy. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23221] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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17
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Lu X, Xue G, Wang X, Han J, Han X, Hankett J, Li D, Chen Z. Directly Probing Molecular Ordering at the Buried Polymer/Metal Interface 2: Using P-Polarized Input Beams. Macromolecules 2012. [DOI: 10.1021/ma301088g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Xiaolin Lu
- Department of Chemistry, Key
Laboratory of Advanced Textile Materials and Manufacturing Technology
of Education Ministry, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Gi Xue
- Department of Polymer Science, Nanjing University, Nanjing, 210093, China
| | - Xinping Wang
- Department of Chemistry, Key
Laboratory of Advanced Textile Materials and Manufacturing Technology
of Education Ministry, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Jianglong Han
- Department of Polymer Science, Nanjing University, Nanjing, 210093, China
| | - Xiaofeng Han
- Department of Chemistry, University of Michigan, 930 North University Avenue,
Ann Arbor, Michigan 48109, United States
| | - Jeanne Hankett
- Department of Chemistry, University of Michigan, 930 North University Avenue,
Ann Arbor, Michigan 48109, United States
| | - Dawei Li
- Department of Polymer Science, Nanjing University, Nanjing, 210093, China
| | - Zhan Chen
- Department of Chemistry, University of Michigan, 930 North University Avenue,
Ann Arbor, Michigan 48109, United States
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Hankett JM, Zhang C, Chen Z. Sum frequency generation and coherent anti-Stokes Raman spectroscopic studies on plasma-treated plasticized polyvinyl chloride films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4654-4662. [PMID: 22309397 DOI: 10.1021/la2045527] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Polyvinyl chloride (PVC) is a widely used polymer to which various phthalates are extensively applied as plasticizers. PVC materials are often treated with plasma to vary the hydrophobicity or for cleaning purposes, but little is known of the nature of the surface molecular structures after treatment. This research characterizes molecular surface structures of PVC and bis-2-ethylhexyl phthalate (DEHP)-plasticized PVC films in air before annealing, after annealing, and after exposure to air-generated glow discharge plasma using sum frequency generation (SFG) vibrational spectroscopy. In addition, we compare the vibrational molecular signatures on the surfaces of PVC with DEHP (at a variety of percent loadings) to those of the bulk detected using coherent anti-Stokes Raman scattering (CARS). X-ray photoelectron spectroscopy (XPS) and contact angle measurements have been used to analyze PVC surfaces to supplement SFG data. Our results indicate that DEHP was found on the surfaces of PVC films even at low weight percentages (5 wt %) and that DEHP segregates on surfaces after annealing. The treatment of these films with glow discharge plasma resulted in surface-sensitive reactions involving the removal of chlorine atoms, the addition of oxygen atoms, and C-H bond rearrangement. CARS data demonstrate that the bulk of our films remained undisturbed during the plasma treatment. For the first time, we probed the molecular structure of the surface and the bulk of a PVC material using combined SFG and CARS studies on the same sample in exactly the same environment. In addition, the methodology used in this research can be applied to characterize various plasticizers in a wide variety of polymer systems to understand their surface and bulk structures before and after systematic applications of heat, plasma, or other treatments.
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Affiliation(s)
- Jeanne M Hankett
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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Vázquez AV, Holden B, Kristalyn C, Fuller M, Wilkerson B, Chen Z. Surface and buried interfacial structures of epoxy resins used as underfills studied by sum frequency generation vibrational spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2011; 3:1640-1651. [PMID: 21504140 DOI: 10.1021/am2001899] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Flip chip technology has greatly improved the performance of semiconductor devices, but relies heavily on the performance of epoxy underfill adhesives. Because epoxy underfills are cured in situ in flip chip semiconductor devices, understanding their surface and interfacial structures is critical for understanding their adhesion to various substrates. Here, sum frequency generation (SFG) vibrational spectroscopy was used to study surface and buried interfacial structures of two model epoxy resins used as underfills in flip chip devices, bisphenol A digylcidyl ether (BADGE) and 1,4-butanediol diglycidyl ether (BDDGE). The surface structures of these epoxies were compared before and after cure, and the orientations of their surface functional groups were deduced to understand how surface structural changes during cure may affect adhesion properties. Further, the effect of moisture exposure, a known cause of adhesion failure, on surface structures was studied. It was found that the BADGE surface significantly restructured upon moisture exposure while the BDDGE surface did not, showing that BADGE adhesives may be more prone to moisture-induced delamination. Lastly, although surface structure can give some insight into adhesion, buried interfacial structures more directly correspond to adhesion properties of polymers. SFG was used to study buried interfaces between deuterated polystyrene (d-PS) and the epoxies before and after moisture exposure. It was shown that moisture exposure acted to disorder the buried interfaces, most likely due to swelling. These results correlated with lap shear adhesion testing showing a decrease in adhesion strength after moisture exposure. The presented work showed that surface and interfacial structures can be correlated to adhesive strength and may be helpful in understanding and designing optimized epoxy underfill adhesives.
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Affiliation(s)
- Anne V Vázquez
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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20
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Probing polymer surfaces and interfaces using sum frequency generation vibrational spectroscopy - a powerful nonlinear optical technique. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11458-010-0220-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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