Fracture of polymeric gels*

A polymeric gel is a cross-linked polymer network swollen with a solvent. If the concentration of the solvent or the deformation is increased to substantial levels, especially in the presence of flaws, then the gel may rupture. Although various theoretical aspects of coupling of fluid permeation with large deformation of polymeric gels are reasonably well-understood and modeled in the literature, the understanding of the effects of fluid diffusion on the damage and fracture of polymeric gels is still in its infancy. A simple model which has the predictive capacity is still lacking.

In this talk, we will show a recent proposed model for fracture of polymeric gels, by embedding the following central idea in the model: the chain of polymers start to break as the stored internal energy attain a certain value. Many interesting phenomena of soft materials can be explored then: i). Swelling induced fracture. ii). Delayed fracture, and iii). Rate-dependent toughness due to diffusion. Also in the talk, we will systematically explore the fast deswelling induced fracture in a typical soft material, by theoretical, experimental and numerical analysis.