Rheology of twist-grain-boundary- A liquid crystals

Abstract

We report studies on the rheological properties of a liquid crystalline analog of Abrikosov phase in type-II superconductors known as twist-grain-boundary-A (TGBA) phase. The TGBA phase shows a large apparent yield stress compared to the cholesteric (N*) phase. The storage modulus (G′) of the TGBA phase is significantly larger than the loss modulus (G′′). The dynamic relaxation measurements indicate a solid-like behavior of N*, TGBA, and smectic-C* phases. The complex shear modulus of the TGBA phase exhibits a power-law behavior G*(ω) ∼ ωα with α≃0.5. The relative amplitude of G′ and G′′ at various temperatures indicate that the enhanced elasticity of TGBA phase is due to the structural defects. © 2014 American Physical Society.