Glass Transition Temperature and Dynamics of $\alpha$-Process in Thin Polymer Films

Abstract

The glass transition temperature $T_g$ and the temperature $T_{\alpha }$ corresponding to the peak in the dielectric loss due to the $\alpha$-process have been simultaneously determined as functions of film thickness $d$ through dielectric measurements for thin films of polystyrene. A decrease of $T_g$ was observed with decreasing film thickness, while $T_{\alpha }$ was found to remain almost constant for $d>d_c$ and decrease drastically for $d<d_c$. Here, $d_c$ is a critical thickness dependent on molecular weight. The thickness dependence of $T_g$ is related to the distribution of relaxation times of the $\alpha$-process, not to the relaxation time itself.

4 pages, 4 figures

References in corpus (2)

• Dynamical heterogeneities in a supercooled Lennard-Jones liquid
• Kinetic Heterogeneities in a Highly Supercooled Liquid

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