The liquid-vapour interface of nematic liquid crystals

Abstract

The occurrence of wetting by a nematic film at the diffuse interface between vapour and isotropic liquid is studied using a generalized van der Waals theory for liquid crystals. This contrasts with earlier studies of nematic wetting at the liquid free surface, which were based on a sharp-interface approximation. The present work also corrects several findings of an earlier study [9] on vapournematic interfaces. Variations in the wetting and alignment properties of the liquid-vapour interface are related to certain orientational symmetry-breaking terms in the model intermolecular potential. Of most relevance to experimental studies, we show that the non-monotonic variation of surface tension with temperature is a necessary consequence of the approach to complete nematic wetting.