DEFORMATION-INDUCED ANOMALOUS SWELLING OF TOPOLOGICALLY DISORDERED GELS

We discuss the scaling theory of topologically disordered swollen netw orks and apply it to the study of uniaxially and biaxially stretched g els. While ins-solvents the response to deformation is qualitatively s imilar to that of usual elastic solids, the theory predicts that under good solvent conditions there exists a range of intermediate deformat ions for which the gel swells normal to the stretching direction and i ts elongational modulus is reduced. At larger deformations there is a crossover into a new regime in which the gel is stabilized by nonlinea r restoring forces. The experimental ramifications of our results are discussed.