Reorganization of Langmuir monolayers on solid surfaces

Langmuir–Blodgett (LB) monolayers of behenic acid, beeswax and long-chain amphiphilic amides were prepared on graphite and mica surfaces by the horizontal precipitation method. The monolayer films and products of their reorganization were studied with atomic force microscopy. LB films of amphiphilic amides were found to self-organize into superstructures with a hexagonal arrangement of hydrocarbon tails. Repeatedly observed supramolecular formations suggest that reorganization is a common phenomenon in monolayers on substrates. It is suggested that the driving force for the molecular reorganization is the surface tension gradient arising from the change in type of hydrocarbon tails packing.