A Unified Model for Non-Fickian Diffusion and Anomalous Swelling of Glassy Polymer Gels.

A sheet of glassy polymers placed in a solvent shows swelling behaviors quite different from that of soft polymers (rubbers and gels). (1) Non-Fickian diffusion (called case II diffusion): As solvent permeates into the sample, a sharp front is created between the swollen part and the glassy part, and it moves toward the center at constant speed. (2) Nonmonotonous swelling: The thickness of the sample first increases and then decreases toward the equilibrium value.

Accelerating the stimuli-responsive bending of a gel using mechanical constraints.

Gel bends in response to external stimuli, which has important technical applications ranging from artificial muscle to drug delivery. Here, we predict a simple and effective method to accelerate the bending of gel using mechanical constraints. We propose an exact theory of the bending dynamics of gel, which gives analytical solutions for the time evolution of the gel curvature and the relaxation time with which the system approaches to its final equilibrium state.