ABSTRACT
N. A. Peppas and C. T. Reinhart and D. L. Meadows and N. A. Peppas described the sieving mechanism in terms of the network mesh size. There are several models which can be used to describe solute diffusion in hydrogels. Classical mechanics and irreversible thermodynamics theories can be used to describe the transport process. The solute diffusion coefficient can be written in terms of various structural parameters of the hydrogel, including the swelling ratio, degree of crystallinity, degree of swelling and branching. A set of mathematical expressions may be used to describe the relation between fluxes and forces in multicomponent diffusion in hydrogels. The chapter discusses basic information about the physical theories which establish the dependence of the solute diffusion coefficient on the polymer structure. Several theories have been developed to predict the diffusion coefficient of a solute in a continuum, including hydrodynamic theories, the Eyring theory, and the Enskog theory.
