Peculiarities of formation and growth of thin polymer plasma-deposited films

Special features of the formation and growth of polymer films, formed on steel under the effect of glow discharge in heptane were studied by means of atomic force microscopy, X-ray photoelectron spectroscopy and contact wetting angle. At low film thickness a thin sticky layer is formed, from which macromolecular cone-shaped formations protrude. With an increase in film thickness the sticky layer disappears and the number of cone-shaped formations increase and they eventually coalesce. As the surface coverage with cones increases the films become thicker and stronger. The cones are assumed to be the film growth sites, which arise during the relaxation of the film's internal stresses. In addition these growth sites can form under the effect of the stresses from extended defects in the substrate.