Experiments and finite element simulations pertinent to hydrogel debonding from a solid substrate

In previous work, the authors proposed a model of swelling-induced debonding that combines the classical work by Flory and Rehner with the variational theory of fracture mechanics by Griffith. These works explore the synergy between theory, laboratory experiments and finite element simulations. We study the swelling of partially bonded, three-dimensional gels, drawing on previous studies of the analogous two-dimensional geometries with the gel confined between parallel walls that suppress swelling in the perpendicular direction. One main goal is the calculation of the energy release rate associated with debonding. Assuming an adhesive toughness that does not change with time, the energy release rate allows us to find the threshold thickness of the membrane above which the gel is unstable to debonding. We also present numerical strategies that allow us to approximate such a threshold thickness, avoiding the computationally taxing fully three dimensional calculations.