Surface Energy Of The Biaxial Nematic Liquid Crystal

Nowadays the surface physics of liquid crystal is an important development field of theliquid crystal science. The interface is created when liquid crystal is placed in contact with thesolid surface and physics of which has been a hot research issue. Because the thickness of liquidcrystal layer in liquid crystal display device is only the microns order of magnitude, there is animportant influence induced by the anchoring action at the surface of substrate on the state ofliquid crystal inside the liquid crystal cell. The most important research content of the interfacephysics is anchoring effect, which is generally described by the anchoring energy.The main content of this study are as follows:(1) The microscopic theory of surface energy for the biaxial nematic liquid crystalThe surface energy caused when the biaxial nematic liquid crystal is in contact with thesolid can be seems as the sum of interaction potential energy between the biaxial nematic liquidcrystal molecules and substrate surface molecules. Then, on the foundation of Straley's pairpotential, the pair potential is minimum when the two molecules are completely parallel, thenusing the Sonnet A M's method, we derive the Ground-state energy of pair potential of liquidcrystal molecules and substrate surface molecules.(2) The link between macroscopic theory and microscopic theory of surface energy for thebiaxial nematic liquid crystalIn this paper, on the foundation of Straley's pair potential and the microscopic theory ofsurface energy for the biaxial nematic liquid crystal, we calculate the statistical average of the orientations of a liquid crystal molecule in the pair potential of a liquid crystal molecule and asubstrate surface molecule. By summing the substrate surface molecule and assuming thenumber of substrate surface molecules N, we derive surface energy of the biaxial nematic liquidcrystal.Based up on the formula derived by Liu Hong and the formula by Zhang Lu, we derive thefree energy of the system. Then using the Sandro Faetti's method, we derive the distribution forthe director of the biaxial nematic liquid crystal on the groove surface and azimuthal anchoringenergy.