A scanning tunneling microscope study of single crystal polyethylene

The scanning tunneling microscope has been used to image single crystal polyethylene lamellae coated with thin Au or Cr overlayers. The images show a variety of different morphologies ranging from single crystal lamella resting on atomically flat, highly oriented pyrolitic graphite substrates to large pyramidal structures formed by a multilayer growth process. Small outgrowth structures were observed on the top surface of many individual lamellae and were found to be in registry with the edge of the underlying “seed” lamella. The STM studies show evidence for sectorization of the single crystal lamella as well as plastic deformation of overlapping lamellae involving c-axis slip.