Nonmonotonic Glass Transition Temperature of Polymer Films Supported on Polymer Brushes
| Autor: | Yeongsik Kim, Wooseop Lee, Hoyeon Lee, Venkat Ganesan, Du Yeol Ryu, Vaidyanathan Sethuraman |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Organic Chemistry 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology Grafting 01 natural sciences 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Chain length chemistry Materials Chemistry Radius of gyration Polystyrene Thin film Composite material 0210 nano-technology Glass transition Layer (electronics) |
| Zdroj: | Macromolecules. 51:4451-4461 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/acs.macromol.8b00290 |
| Popis: | We modulated the grafting density (σ) and chain length of polystyrene (PS) brushes on substrates to probe their effect on the glass transition temperature (Tg) in overlaying PS thin films. The Tg of PS films was analyzed as a function of brush thickness (or σRg2), where Rg is the radius of gyration of PS brushes. Our results indicate that PS films below 90 nm exhibit a nonmonotonic dependence of Tg on grafting density with the maximum Tg occurring near the regime of wetting–dewetting transition of the overlaying melt. The maximum Tg was found to be higher than the value of bulk PS system. Computer simulation results suggest that such trends arise as a consequence of the environment of enhanced friction presented by the brush layer and the overlap between the polymer film and the grafted layer. |
| Databáze: | OpenAIRE |
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