Nanomesh aluminum films for LC alignment : theoretical and experimental modeling

A porous system for LC alignment is reviewed. Fabrication of nanomesh aluminum films and their porous structure are described. Methods of the nanomesh parameters for optimal LC alignment are discussed. A model of the LC alignment in a porous system is proposed. The LC orientation type is determined by the free anchoring energy and the micropore diameter. The difference between planar and homeotropic anchoring energies appears to be lower than the interaction energy by two orders of magnitude

Distribution of Dye Molecules Orientation in Photoaligning Layer Versus Incidence Angle of Polarized Light Beam

A mechanism of dyes molecules orientation by laser radiation is proposed that takes into account anisotropy of molecular optical polarizability. A dependence of dye molecules energy on polarizability anisotropy, order parameter, quantity of molecules in a cluster, strength of light wave electrical field, light beam incidence angle is derived

Anchoring Energy of Liquid Crystals

The liquid crystals anchoring theory is considered on the molecular level. Earlier calculations of mesogenic molecules interaction energy with graphite and PE surface give results being one-two orders higher than experimentally obtained values. To explain the experimental values of anchoring energy we proposed its dependence on the interaction between liquid crystal layers. In our calculations we have simulated the mesogen molecules by virtual rod-like molecules. The molecules orientation was given by polar and azimuthal angles towards the directors of neighboring liquid crystal layers. Obtained values of polar and azimuthal anchoring energy as well as their dependences on the order parameter are in good agreement with experimental data

Influence of the order parameter on the anchoring energy of liquid crystals

No theory of the polar and azimuthal anchoring energies of liquid crystals (LCs) has been developed on a molecular level, despite the scientific and practical topicality of the problem. The interaction energies of mesogenic molecules with graphite and polyethylene surfaces calculated previously by the method of atom-atom potentials are in good agreement with the experimental data, but, at the same time, the calculated polar and azimuthal anchoring energies are larger than their experimental values by one and two orders of magnitude, respectively. To explain these values, the anchoring energy has been assumed to depend not only on the interaction with the surface but also on the interaction between the LC molecules arranged in the model in the form of quasi-layers. The mesogenic molecules have been modeled by rods with virtual C' atoms (carbon atoms with hydrogen atoms attached to them) "threaded" on them. The molecule orientation has been specified by the polar and azimuthal angles theta (i) , phi (i) and theta (j) , phi (j) relative to the directors of the ith and jth layers. The derived polar and azimuthal anchoring energies as well as their dependences on the order parameter have turned out to be close to the experimental data