Defects, elasticity and flow in lamellar phases

Abstract

We present intriguing results from light microscopy and rheometry on a lyotropic lamellar liquid crystal. We find that the rigidity of the structure 1s in practlce controlled mainly by a striking network of oily-streak defects, rather than by the continuum elasticity of the perfectly aligned phase. This network decays under shear, but this decay is retarded substantially by the addition of micron-sized particles which anchor onto its nodes, yielding a particle-stabilised network gel made of line defects. This work was done in collaboration with Geetha Basappa, Suneel, V. Kumaran, Prabhu R Nott (IISc) and V.M. Naik and D. Rout (Unilever Research Inia)