Phase Transition in Surface-Aligned Nematic Films

Abstract

Properties of the nematic-isotropic phase transition in surface-aligned nematic films are calculated using the Landau-de Gennes theory. It is shown that there is a critical thickness ${D}^{c}$ of the film below which the transition from the nematic phase to the isotropic phase becomes continuous. At the critical thickness the transition is second order and exhibits critical behavior. For $N\ensuremath{-}[e\ensuremath{-}\mathrm{methoxybenzylidine}]p\ensuremath{-}\mathrm{butylaniline}$, ${D}^{c}$ is calculated to be about 1000 \AA{}, and the critical temperature is 0.17 K above the bulk first-order transition temperature. Magnetic and dimensional effects are discussed.