Surface structure of polymers and their model compounds observed by atomic force microscopy

Results of atomic force microscopy (AFM) of normal alkanes, polyethylene, isotactic polypropylene and of a diblock copolymer are presented. Various types of surfaces - naturally and epitaxially grown on different substrates - have been examined from hundreds of nanometers down to the atomic scale. Surface morphology and molecular arrangement have been visualized in AFM images. Atomic-scale AFM images with some defects have been observed on lamellar surfaces of normal alkanes C33H68. Arrays of oriented polyethylene molecules have been revealed at the surface of thin polyethylene films, epitaxially crystallized on the (001) face of an anthracene single crystal. Contact faces of thin films of isotactic polypropylene (iPP), epitaxially crystallized on various substrates (i.e. benzoic acid, potassium salt of 4-chloro-benzoic acid or polyamide 11), show the lamellar structure as well as the methyl side-group pattern in the exposed iPP (010) planes. AFM offers the way to distinguish the crystalline modification as well as the molecular conformation (left- and right-handed helices). Also the morphology of a microphase-separated block copolymer, polystyrene-b-poly-(2-vinylpyridine) (PS/PVP), has been observed by AFM.