Kinetics of swelling for a cross-linked elastomer or gel in the presence of a good solvent

We obtain the equations describing the swelling of an elastomeric sample when a good solvent diffuses in the elastomeric material. These equations predict the time evolution of the concentration profiles of the polymer. We consider explicitly the case of one-dimensional geometry (infinite slab) as well as the case of a spherical geometry in three dimensions and obtain numerical solutions for these cases. The experimental implications of our results are briefly discussed.