Thickness-dependent phase transition in thin nematic films.

Abstract

Using light scattering, the thickness dependence of the isotropic-nematic phase transition temperature ${\mathit{T}}_{\mathit{NI}}$ in a thin film of octylcyanobiphenyl (8CB) is studied in two distinct geometries: with and without strain. We observed a large stress induced shift in ${\mathit{T}}_{\mathit{NI}}$, as a function of the film thickness d. At d\ensuremath{\sim}0.3 \ensuremath{\mu}m a crossover in the behavior of ${\mathit{T}}_{\mathit{NI}}$ as a function of thickness is observed, which can be attributed to a competition between strain and anchoring forces. \textcopyright{} 1996 The American Physical Society.