DYNAMICS OF THE FREEDERICKSZ TRANSITION IN THE ELECTRIC-FIELD IN NON IDEALLY ORIENTED NEMATIC LAYERS AT SUB-THRESHOLD AND ABOVE THRESHOLD VOLTAGES

The DAP-effect (Deformation of Aligned Phases) in homeotropic layers of ZLI-207 - commercial room temperature liquid crystal of MERCK - a negative dielectric anisotropy mixture ( DELTA epsilon equals minus 0. 6) of azoxycompounds and aromatic esters with additives for spontaneous homeotropic orientation. The homeotropic orientation was nonideal which was obtained by rubbing of the electrodes. The rubbing was made with the aim a plane of preferred deformation to be defined and in this manner to avoid the creation of umblics. The nonideal initial orientation resulted in subthreshold deformations, the dynamics of which is further systematically studied experimentally and theoretically.