Langmuir−Blodgett Mono- and Multilayers of Rodlike Oligo(cyclohexylidene) Derivatives Bearing an Oxime Headgroup

Abstract

The Langmuir film-forming properties of rodlike oligo(cyclohexylidene) oximes and derivatives 1(n)−8 have been studied. It is shown that subtle structural modifications of their hydrocarbon framework, such as end-functionalization by a tert-butyl group or an n-alkyl group or (selective) hydrogenation of double bonds, markedly affect their propensity toward Langmuir monolayer formation and in particular monolayer film stability. Mean molecular areas (π−A isotherms) show that the oximes orient nearly perpendicular on the air−water interface. Film transfer of 5(2) onto moderately hydrophilic silicon (100) wafers gave predominantly Z-type deposition; for a monolayer a tilt angle of 26° was derived (atomic force microscopy). The quantitative elemental composition of a transferred multilayer assembly of 5(2) was determined using elastic recoil detection.