The surface glass-transition temperature (Tgs) in monodisperse polystyrene (PS) films was examined on the basis of the temperature dependence of the lateral force at a given scanning rate. T gs of the PS films was found to be markedly lower than the corresponding bulk glass-transition temperature over the entire molecular weight range (4900-1,460,000). Also, the apparent activation energy of the surface segmental motion in the PS films was 230 ± 10 kJ mol -1, significantly smaller than that for bulk PS. Finally, T gs measurement by lateral force microscopy was applied to binary PS mixtures with different molecular weights. On the basis of the Gordon-Taylor equation, the surface composition of the shorter component in the blend films was successfully obtained.
|Number of pages
|Journal of Polymer Science, Part A: Polymer Chemistry
|Published - Feb 1 2004
All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry