STRUCTURAL INVESTIGATION OF DIPPING LINES IN LANGMUIR-BLODGETT-FILMS BY SCANNING FORCE MICROSCOPY

Langmuir-Blodgett (LB) films of Cd2+ salts of long-chain fatty acids transferred on mica were investigated by scanning force microscopy (SFM) under ambient conditions. Dipping lines separating a single monolayer from three monolayers and separating three monolayers from five monolayers were studied with SFM. The monolayer thickness of the top layer of a multilayer assembly of Cd arachidate is 2.8 nm, whereas the first monoloayer on mica is apparently thinner by SFM. Frequently, the monolayer systems show surface modulations (ripples) with a subnanometer amplitude of the surface corrugations, which extend across the dipping line. Close to the dipping line between three and five monolayers the molecular lattice was resolved on the surface of three as well as five-monolayer assemblies, It is shown that the lattice orientation in subsequent monolayers is not correlated by SFM.