AN ATOMIC-FORCE MICROSCOPY STUDY OF POLYESTER SURFACES

The surface properties of amorphous and crystalline polyester films, w ell below their glass transition temperature, have been studied with a n atomic force microscope. For amorphous films a corrugated pattern de velops on the surface as a result of scanning and the corrugations are always perpendicular to the scan direction. When scanning is stopped the pattern shows a slight relaxation; however, the surface is plastic ally deformed. When crystalline films are scanned, similar patterns ar e seen which are less pronounced and require a much longer scan time. These results suggest that the physical properties of a glassy polyest er surface may be different from the bulk, and the freedom of macromol ecules is reduced upon crystallization, thus suppressing molecular mot ion at the surface.