Surface Deformation Analysis of Poly(Ethylene Terephthalate) With a Different Draw Ratio Using Atomic Force Microscopy

The tensile deformation behaviors of poly(ethylene terephthalate) (PET) surfaces with different draw ratio (lambda) were observed in situ using an atomic force microscope (AFM). Heterogeneous deformation was observed on the PET surfaces with lambda = 2. In contrast, for PET (lambda >= 5), the microscopic deformation by AFM coincided with the macroscopic one. This indicates that the deformation process for the oriented PET (lambda >= 5) surface could be described as an affine deformation. The apparent Poisson's ratio of the PET surface slightly decreased with an increase of . This suggested that the strain in the direction perpendicular to the tensile load was affected by the molecular orientation of the amorphous region.