Computer simulation of an unconfined liquid crystal film

We present results from a molecular dynamics simulation of an unconfined Gay-Berne film in equilibrium with its own saturated vapor. The parametrization and temperature range used are based upon the results of preliminary Gibbs ensemble investigations, which show the existence of bulk liquid-vapor and nematic-vapor coexistence. This parametrization is found to induce a preferred molecular alignment in the nematic film perpendicular to the liquid-vapor interface, in contrast to work on similar systems showing planar alignment. At slightly higher temperatures the nematic phase is wet by the isotropic, displaying an intermediate ordering regime in which the film is comprised of several short-lived nematic domains. This behavior has been analyzed using orientational correlation functions, and shown to be associated with a decoupling of the planar and perpendicular nematic ordering. The interfacial surface tension behavior has also been evaluated, and shown to be consistent with theoretical predictions for systems displaying isotropic wetting.