Abstract
Poly (methyl methacrylate) s, (PMMA) s, were spin-labeled in methanol to study the surface molecular mobility. Transition temperature in molecular motion, T5.0mT, obtained by ESR was found to be lower than that in the bulk. Glass transition temperature near the solid surface can be estimated using the ESR data and WLF equation. The glass transition temperature near the solid surface of PMMA was estimated to be approximately 30-40 K lower than that in the bulk. This fact indicates that the segmental density near the solid surface is lower than that of the bulk polymer. In addition, it was found that the molecular mobility near the solid surface depends on the tacticity of PMMA.
