Effect of free surfaces on the smectic-A-hexatic-B-crystal-E transitions in thin free-standing films of the liquid-crystal compound n-heptyl-4-n- pentyloxybiphenyl-4-carboxylate (75OBC)

An ac free-standing film calorimeter has been recently developed to investigate the physical properties of the smectic-A-hexatic-B-crystal-E transitions in free-standing films of the liquid-crystal compound n-heptyl-4-n-pentyloxybiphenyl-4-carboxylate (75OBC). Due to the surface-enhanced order on free surfaces, we have discovered many new physical phenomena, e.g., a rich phase diagram, layer-by-layer transitions near a continuous transition, an interplay between a strong first-order surface transition and a nearby continuous transition, etc.