DIRECTOR TEXTURES OF THE NEEL INVERSION WALL IN A LIQUID-CRYSTAL POLYMER

A solution of the director orientation function is presented for Neel inversion walls created in a liquid crystal by application of a magnet ic field. The theoretical model is used to simulate director trajector ies across walls as a function of both the elastic anisotropy and the orientation of the wall with respect to the applied field. The gradual transition of the defect structures from Neel bend walls to Neel spla y walls as the angle between the wall and the magnetic field is varied is also presented. Micrographs obtained via atomic force microscopy o n a thermotropic liquid crystalline polymer are used to test and evalu ate the theoretical model. Visualization of director textures using th e lamellar decoration technique shows the theoretical and experimental results to be in good agreement. The results were used to determine t hat the sample lad an elastic anisotropy of approximately 0.5, implyin g that k(11) = 3k(33).