Elastic constant anisotropy and disclination interaction in nematic polymers II. Effect of disclination interaction

Abstract

A new tensorial approach introducing unequal elastic constants in a two-dimensional lattice model is applied to simulate the influence of disclination interaction on the structures of half-wedge disclinations, for the understanding of the variation of apparent elastic anisotropy ϵ {\rm _{a}} measured from different disclinations in a texture (see preceding paper, part I [1]). The apparently random variation of ϵ {\rm _{a}} implies that disclination interaction has a strong effect on the structure of disclinations; as elastic anisotropy increases, its impact becomes overpowering. Nevertheless the disclination interaction still acts in the same way as in the case of equal elastic constants. Analysis of the free energy of disclination pairs shows that the structures of both +1/2 and −1/2 disclinations are changed under the influence of a neighbouring disclination, but in different ways. For +1/2 disclination, the splay and bend distortions vary with the relative orientation of its −1/2 neighbour. Meanwhile, for −1/2 disclination, the bend and splay distortions are remarkably insensitive to the relative orientation of its +1/2 disclination neighbour.

Acknowledgments

W. S. would like to acknowledge the support of an Overseas Research Student (ORS) Scholarship, a Cambridge Overseas Trust Scholarship, and the Department of Materials Science and Metallurgy, University of Cambridge. Support by the EPSRC grant under its ‘processing of conventional structural materials' program is appreciated.