The Contribution of the Smectic-Nematic Interface to the Surface Energy

TL;DR

This paper investigates how the smectic-nematic interface influences the surface energy in liquid crystals, revealing its dependence on transition region thickness and temperature, with implications for understanding surface interactions.

Contribution

It introduces a simple model showing the smectic-nematic interface significantly affects surface energy, surpassing substrate interactions, and exhibits non-monotonic temperature dependence.

Findings

Surface energy depends on the smectic-nematic transition thickness.

The transition region thickness is about the correlation length.

Surface energy varies non-monotonically with temperature.

Abstract

The contribution of the smectic-nematic interface to the surface energy of a nematic liquid crystal sample is analyzed. By means of a simple model it is shown that the surface energy depends on the thickness of the region over which the transition smectic-nematic takes place. For perfectly flat substrates this thickness is of the order of the correlation length entering in the transition. An estimate of this contribution shows that it is greater than the one arising from the nematic-substrate interaction. Moreover, it is also shown that the surface energy determined in this way presents a non-monotonic behavior with the temperature.