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Updated: Jun 24, 2025
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Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
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Quantifying Chemical Reactions and Interfacial Properties at Buried Polymer/Polymer Interfaces
Daniel Rossi1, Yifan Dong2, Rajesh Paradkar2
1Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|June 6, 2024
Summary
Maleic anhydride (MAH) modified polymers enhance adhesion in multilayer films. Researchers used SFG spectroscopy to quantitatively link MAH concentration to interfacial chemistry, structure, and adhesion strength.
Area of Science:
- Materials Science
- Polymer Chemistry
- Surface Science
Background:
- Maleic anhydride (MAH)-modified polymers are crucial tie layers in multilayer polymer films, enabling adhesion between dissimilar polymers.
- While MAH's bulk chemistry is understood, its interfacial behavior, critical for adhesion, is a recent area of study.
- Sum frequency generation vibrational spectroscopy (SFG) is a powerful interfacial technique for probing chemical reactions and molecular orientations.
Purpose of the Study:
- To quantitatively characterize the interfacial chemistry and structure between MAH-modified polyethylene and barrier polymers (nylon and EVOH).
- To investigate the influence of varying MAH concentrations on interfacial reactions and molecular orientation.
- To correlate interfacial properties with macroscopic adhesion strength for improved tie layer design.
Main Methods:
- Utilized Sum Frequency Generation (SFG) vibrational spectroscopy to analyze model systems of MAH-modified polyethylene with nylon and EVOH.
- Investigated a range of MAH concentrations to determine detection limits for interfacial reaction products.
- Analyzed concentration-dependent SFG peak positions and polarization-dependent spectra to extract information on chemical species and molecular tilt angles.
Main Results:
- Detected interfacial reaction products between MAH and nylon at MAH concentrations as low as 0.022 wt % and with EVOH at 0.077 wt %.
- Quantitatively observed concentration-dependent changes in interfacial chemistry and structure through SFG peak analysis.
- Demonstrated a strong correlation between interfacial chemistry, molecular orientation, and measured adhesion strength.
Conclusions:
- SFG spectroscopy provides quantitative insights into the interfacial chemistry and structure of MAH-modified polymers.
- MAH concentration significantly impacts interfacial reactions, molecular orientation, and ultimately, adhesion.
- The findings offer crucial quantitative data for the rational design of high-performance MAH-modified tie layers.
