Thickness-dependent phase transition in thin nematic films

Using light scattering, the thickness dependence of the isotropic-nematic phase transition temperature TNI 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 TNI, as a function of the film thickness d. At d{~}0.3 {μ}m a crossover in the behavior of TNI as a function of thickness is observed, which can be attributed to a competition between strain and anchoring forces. {} 1996 The American Physical Society.