Orientational Elastic Constants of Polymer Comblike Nematic

Abstract

Elastic deformations of uniformly orientated layers of thermotropic polymeric comblike nematic in magnetic field were studied using the method of Freedeneknz transitions. The temperature dependences of splay K_l and bend K₃ elastic constants and optical anisotropy were determined. On changing of the relative temperature ΔT = T - T₀ from -0.5 to -60°C, the optical anisotropy increases from 0.05 to 0.1. This experimental fact shows double increase of order parameter. It was found that in investigated temperature range the splay constant values are slightly more then the bend constant values (K₁/K₃ ∼ 0.8).