Kinetics of Surface Crystallization in Thin Films of Poly(ethylene terephthalate)
| Autor: | Richard A. L. Jones, Anthony M. Higgins, Dean Trolley, M. Durell, Simon Brown, P. C. Jukes, J. Emyr Macdonald, Arindam Das, Mark Geoghegan, Paul Thompson |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Materials science
Polymers and Plastics Organic Chemistry Analytical chemistry Atmospheric temperature range Surface energy law.invention Inorganic Chemistry law Angle of incidence (optics) Free surface Polymer chemistry Materials Chemistry Crystallization Thin film Penetration depth Glass transition |
| Zdroj: | Macromolecules. 38:2315-2320 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma0490606 |
| Popis: | In-situ grazing incidence X-ray diffraction has been used to investigate the kinetics of crystallization at the surface of thin films of poly(ethylene terephthalate) (PET). By varying the angle of incidence of the X-ray beam around the critical angle of the film, the penetration depth can be tuned to allow a direct comparison of molecular ordering in the surface and bulk of the film. The results show that ordering occurs significantly faster at the surface in the temperature range 90−100 °C (close to the bulk glass transition temperature of 75 °C). The (0 1 1) and (0 1 0) peaks narrow more rapidly and achieve a lower width, indicating that the crystallization progresses more rapidly in these crystallographic directions. This enhanced ordering is attributed to a combination of surface energy effects, which promote localized packing, and to an enhanced segmental mobility near the free surface. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|