Langmuir-Blodgett Films of Amphiphiles with Cyano Headgroups

Abstract

Surface pressure-area isotherms for a number of structurally related aromatic cyano derivatives were recorded. T15 (4-cyano-4″-n-pentyl-p-terphenyl) gave the most cohesive monolayer owing to a greater degree of intermolecular π orbital overlap. This compound gave Z-type multilayer deposition and an explanation for this transfer behaviour is proposed based on dipole-dipole interactions between adjacent layers. An X-ray diffraction study showed the layer thickness to be 20.5 ± 0.5Å and a molecular packing model consistent with this value is presented. Preliminary comparisons are made with the monolayer and multilayer behaviour of long-chain alkyl cyanides.