Influence of copolymer composition on non‐fickian water transport through glassy copolymers

The dynamic swelling behavior of poly(2‐hydroxyethyl methacrylate‐co‐methyl methacrylate) and poly(2‐hydroxyethyl methacrylate‐ co ‐ N ‐vinyl‐2‐pyrrolidone) in water was followed at 37°C. The results were analyzed in terms of a simple non‐Fickian transport equation, which expresses the fractional penetrant uptake as an exponential function of the diffusion time. The exponent n , which indicates Fickian or non‐Fickian transport mechanism, was correlated to the content of the more hydrophilic component of the copolymer. Photomicrographs obtained with polarized light offer new information about the position and movement of the penetrant front in glassy, hydrophilic polymers.