Swelling of Gels and Diffusion of Molecules
The kinetics of swelling and shrinking of gels is studied. A new relation, in addition to the differential equation developed by Tanaka and Fillmore, is formulated to solve the kinetics of gels having arbitrary shape. The gel kinetics is described as a combination of the collective diffusion with finite rate and immediate relaxation of shear deformation. The relation demonstrates the fundamental differences between the gel kinetics and the molecules diffusion process. The difference is a direct result of the existence of the shear modulus of the gel network system. Some interesting details of our theory are further discussed.
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