AFM In-situ Bending Test on Deformation Behavior of Polyethylene Lamellar Structure

Abstract

In the present study, the deformation behavior of lamellae of polyethylene has been directly observed using the Atomic Force Microscopy in-situ bending test. A cantilever type specimen of polyethylene is bent on the AFM stage, and the surface profile is scanned in a time sequence. The rotation angle, shear and elongation of more than one hundred lamellae are quantitatively evaluated from the successive height profiles of AFM images. The result suggests that the deformation of each lamella is basically correlated with the global strain of scanned area, however, some lamellae show different behavior as "inclusion". We also observed the onset of a craze in a time series, which reveals the following two facts ; (1) the surface irregularity leads to the super-fibrils in a craze, (2) a super-fibril is found to break, shrink and annihilate in the later stages of deformation.