Abstract
Hypothesis: We hypothesize that varying the chemical structure of the monomeric unit in a polymer will affect the surface structure and interfacial molecular group orientations of the polymer film leveraging its response to solvents of different chemical affinities. Experiments: Poly (2-methoxy ethyl methacrylate) and poly (2-tertbutoxy ethyl methacrylate) thin films exposed to either deuterated water (D2O) or deuterated chloroform (CDCl3) were studied by sum frequency generation (SFG) spectroscopy, contact angle goniometry, and atomic force microscopy (AFM) at the polymer-solvent interface, supported with molecular simulation studies. Findings: SFG spectral analysis of the polymer thin films corroborated molecular re-organization at the surface when exposed to different chemical environments. The AFM height images of the polymer surfaces were homogeneously flat under CDCl3 and showed swollen regions under D2O. Following the removal of D2O, the exposed areas have imprinted, recessed locations and exposure to CDCl3 resulted in the formation of aggregates. The chemical affinity and characteristics of the solvents played a role in conformational change at the polymer surface. It had direct implications to interfacial processes involving adsorption, permeation which eventually leads to swelling, deformation or aggregation, and possibly dissolution.
Original language | English |
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Pages (from-to) | 221-233 |
Number of pages | 13 |
Journal | Journal of Colloid and Interface Science |
Volume | 616 |
DOIs | |
State | Published - Jun 15 2022 |
Externally published | Yes |
Funding
The authors thank the National Science Foundation under Grant No. CHE-0947031 for the acquisition of the femtosecond laser. The authors would like to thank the Department of Chemistry and Biochemistry, College of Arts and Sciences, Nanoscale and Quantum Phenomena Institute at Ohio University for their additional financial support.
Keywords
- Contact angle measure
- Methacrylate-based polymers
- Polymer aggregation
- Polymer dissolution
- Polymer swelling
- Polymer thin films
- Polymer-liquid interface
- Polymer-solvent interactions
- Sum frequency generation spectroscopy
- atomic force microscopy (AFM)