Glass transition temperature and dynamics of α-process in thin polymer films
Faculty of Integrated Human Studies,
Kyoto University - Kyoto, 606-8501 Japan
Accepted: 30 March 1999
The glass transition temperature Tg and the temperature corresponding to the peak in the dielectric loss due to the α-process have been simultaneously determined as functions of the film thickness d through dielectric measurements for thin films of polystyrene. A decrease of Tg was observed with decreasing film thickness, while was found to remain almost constant for and decrease drastically for . Here, dc is a critical thickness dependent on molecular weight. The thickness dependence of Tg is related to the distribution of the relaxation times of the α-process, not to the relaxation time itself.
PACS: 64.70.Pf – Glass transitions / 68.60.-p – Physical properties of thin films, nonelectronic / 77.22.Gm – Dielectric loss and relaxation
© EDP Sciences, 1999