Electron microscopic studies of microdeformations of amorphous polymers in the glass transition region

Morphological changes occurring in amorphous poly(methyl methacrylate) and polystyrene due to deformation near the glass transition temperatures were studied by transmission electron microscopy. Supermolecular heterogeneities were revealed by using the method of surface decoration of samples with gold prior to deformation. Deformation is accompanied by the formation of a band structure of slightly deformed material which is roughly perpendicular to the direction of deformation. The band width (nonhomogeneity of deformation) increases with temperature and is independent of the magnitude of deformation. In little-deformed domains more rigid particles emerge on the surface, indicating the supermolecular heterogeneity of polymers. The suggested model of microdeformation of amorphous polymers explaining the formation of the surface band structure is consistent with the bulk morphology revealed by high-frequency plasma etching.