ABSTRACT
In this chapter, we analyze the main effects of the presence of a surface limiting the sample on the anchoring properties of nematic liquid crystals. We introduce the concept of anchoring and discuss some proposed forms for the surface energy in a macroscopic perspective. Subsequently, some sources for the surface energy are investigated. The stochastic contribution to the anchoring energy is shown to be responsible for the deviation from the Rapini-Papoular expression for the surface energy. The effect of the spatial variation of the scalar order parameter and of the elastic constant on the surface free energy is discussed in a pseudo-molecular approach. At the end of the chapter, we present an estimation of the contribution of the smectic-nematic interface to the surface energy.
