Calculation of the hydrodynamic permeability of gels and gel-filled microporous membranes

A new approach to the calculation of gel hydrodynamic permeability is prese nted in which the gel is modeled as an assemblage of spheres whose radius i s a function of the gel concentration. Scaling methods coupled with the ele ctrostatic persistence length are used to estimate the correlation length i n equivalent semidilute solutions. The correlation length is taken to be eq ual to the sphere diameter in an assemblage, and the hydrodynamic permeabil ity of the assemblage is calculated using the Brinkman and Happel models. I t is shown that the calculated permeabilities are fully in accord with expe rimental data reported in the literature for membranes with incorporated po ly(acrylamide) gels, as well as data reported in this work for membranes co ntaining charged gels composed of poly(4-vinyl-N-benzylpyridinium salts).