SOLUTE DIFFUSION IN HYDROGELS - AN EXAMINATION OF THE RETARDATION EFFECT

A new expression which describes the retardation of salutes within sti ff-chained, swollen hydrogels was developed based on the idea that sol ute transport is determined by the probability of the solute finding a n opening between the polymer chains greater than the radius of the so lute molecule. The retardation factor expression derived was tested ag ainst experimentally determined diffusivities of globular proteins rel eased from protein-loaded calcium alginate hydrogels, as well as from experimental and simulation data from the literature. The expression p rovided close agreement with the observed effects of polymer volume fr action, solute hydrodynamic radius, and polymer chain radius on solute diffusivity. (C) 1998 Elsevier Science Ltd. All rights reserved.