Elasticity of smectic liquid crystals with focal conic domains
Abstract
We study the elastic properties of thermotropic smectic liquid crystals with focal conic domains (FCDs). After the application of the controlled preshear at different temperatures, we independently measured the shear modulus G' and the FCD size L. We find out that these quantities are related by the scaling relation G' ~ γeff/L where γeff is the effective surface tension of the FCDs. The experimentally obtained value of γ eff shows the same scaling as the effective surface tension of the layered systems KB where K and B are the bending modulus and the layer compression modulus, respectively. The similarity of this scaling relation to that of the surfactant onion phase suggests an universal rheological behavior of the layered systems with defects.