Temperature Dependence of the Buried Glass-Smectic Liquid Crystal Interface

Abstract

We have studied the temperature behavior of the buried Glass-Liquid Crystal Interface for 8CB films of varying thickness deposited into a grated surface, using grazing incidence X-ray scattering. Our results indicate the presence of both a chevron structure and a structure similar to the helical twist-grain-boundary (TGB) phase the evolve as a function of temperature. We find that smectic order is preserved at temperatures well above the smectic A - nematic transition, especially in films of intermediate thickness. A depth analysis of the films indicates that the intensity of the scattering peak increases close near the center of the intermediate thickness films. This evolution is accompanied by a rotation of the smectic layers due to flow in the sample.

Key Words:

• interface structure
• confinement
• grazing incidence
• X-ray scattering
• competing interactions
• TGB structure
• chevron structure