Birefringence in swelling crosslinked polymer beads

Abstract

Abstract The radial distribution of birefringence in a swelling polystyrene–divinylbenzene copolymer bead is measured from the optical patterns observed with a polarizing microscope. This birefringence arises from the restraining influence of the nonswollen core on the exterior shell of gel. It is found that the birefringence is negative in sign, and exhibits a sharp maximum at the gel‐core interface.