Interference Microscopic Examination of Fluid Films on Metal Surfaces

摘要

Profiles of fluid films on metal surfaces were measured by means of interference microscopy. The purpose of the work was to further characterize the behavior of fluid films and adsorbed films on metals in terms of molecular structure of the fluid components, surface topography and surface energy. The method used was similar to one described by Bascom, Cottington and Singleterry of the Naval Research Laboratory. Film profiles were measured down to thickness of about 1000 angstroms by this method. The results confirmed the mechanism for spreading of liquids which was advanced by Bascom and co-workers. Squalane films containing 0.01% by weight oleic acid did not spread on polished stainless steel or platinum. Films containing 0.01% by weight and 0.3% by weight oleic acid did spread on platinum, but at a slower rate than did the pure squalane. Results are interpreted in terms of known surface energy relationships. Effects of surface contamination by particles and by adsorbed films can be readily observed by the method of interference microscopy. Under some conditions the micro-relief structure of the metal surface can also be observed and estimates made of the heights of the surface elevations. (Author)