Evidence of shear‐induced polymer release from a swollen gel particle

Abstract

Abstract The influence of simple shear flow on the behaviour of an isolated polyelectrolyte hydrogel particle swollen in an aqueous hydroxypropylcellulose solution was studied by rheo‐optics. When submitted to a constant shear stress, an initially spherical particle deforms quickly to adopt a stable ellipsoidal form. Upon reaching a first stress threshold, some liquid is released from the particle. This liquid release is determined by a critical deformation value above which the gel cannot retain all of its solvent. At stresses above a second threshold value, small droplets of liquid are secreted from the particle and move away in the flow direction. © 2003 Society of Chemical Industry