Layer growth in collapsed liquid crystal monolayers studied by scanning force microscopy

Scanning force microscopy operating under topographic and electric force modes has been used to study the collapse of monolayers of the liquid crystal 4'-n-octyl-4-cyanobiphenyl (8CB). Topographic images show that the collapse proceeds by the formation of an interdigitated bilayer on top of the monolayer. In the early stages of collapse, the bilayer has the form of circular islands 0.5-0.6 mu m in diameter and 26-28 Angstrom, high. The islands aggregate as the collapse proceeds. Surface potential measurements confirm the interdigitated arrangement of molecules in the bilayer. There is no evidence that the collapse occurs by folding of the monolayer.