Analysis of poly(ethylene terephthalate) (PET) films by atomic force microscopy

An atomic force microscope operating in a contact mode can provide 5-×5-nm atomic-scale images of a poly(ethylene terephthalate) (PET) film that allows the identification of what are believed to be phenyl groups and phenyl chains. Large-scale, 5-×5-μm images reveal the presence of raised surface features attributed to the extrusion process used to form the PET film. These surface irregularities could affect the film's physicochemical properties. Furthermore, regions with different overall surface roughnesses have been identified, showing that surface roughness can distinguish between the amorphous and crystalline regions that form this type of film. Imaging forces have been found capable of altering the film surface, and surface disorder increases with imaging time.