Optical studies on the surface-induced tilted layers in freestanding films of two no-layer-shrinkage liquid crystal compounds

Null transmission ellipsometry has been employed to study the molecular arrangements in freestanding films of two no-layer-shrinkage liquid crystal homologous compounds above the bulk smectic A -smectic C* (Sm C*) transition temperature. An unusual nonplanar-parallel or nonplanar-antiparallel- parallel transition has been observed in both compounds under a proper electric field. With the addition of one CH2 group, while the Sm C* phase is more stable thermally, the magnitude of the critical field needed to induce a parallel-antiparallel transition decreases dramatically.