Stabilisation of spread monolayers of an amine-functionalised biphenyl mesogen by association with a carboxymethyl cellulose salt

The monolayer-forming capabilities of a tertiary amine-capped dialkyloxy biphenyl mesogen at the air-water interface were studied. It was found that stable monolayers are obtained in the presence of a water-soluble polymer in the subphase, notably the sodium salt of carboxymethylcellulose. Furthermore, the formation of a surface-adsorbed polymer layer, either by aspiration of the depletion layer or by heating, prior to the spreading of the mesogen resulted in higher surface pressures. The stable monolayers were successfully transferred to glass and aluminium substrates to give multilayer Langmuir-Blodgett films. Reflection Infrared Spectra of the transferred films were obtained, and they indicated that both components are indeed present and that the biphenyl moiety and alkyl spacer of the mesogen both have a net orientation perpendicular to the film surface.