Wide Stripe Texture of Liquid Crystalline Polymer after Cessation of Shear Flow

Abstract

Textures called wide stripe textures (WSTs) emerge after cessation of a simple shear flow of liquid crystalline polymers (LCPs). The present study considered the WST in a 50 wt% aqueous solution of hydroxypropylcellulose and investigated the distance between stripes. A test fluid was sandwiched between two parallel discs and shear was imposed on the fluid by rotating one of the discs. The experiments were carried out with varying the temperature of fluid, the shear rate γ, and the gap height h. The distance tends to increase with increasing the gap width, slightly depends on γ for small h, and increases with increasing γ for large h. It was suggested that the emergence of WSTs related the relaxation process of relatively large structures such as defects in LCPs.