Drying-induced nucleation patterns in confined hyperelastic hydrogels

In many constrained systems, from paintings to muddy soils, the evaporation of a solvent leads to the formation of complex drying patterns. These patterns are often characterized by brittle straight cracks typical of drying materials with a low characteristic failure deformation. We report novel pattern morphologies that occur during the drying of highly stretchable hydrogels confined between two glass plates. Here, the evaporation front advances by intermittent cavities, which leads to either a disordered or a “worm-like” network structure. We propose a possible mechanism that sets the cavity size, where a balance between elastic and surface energy is expressed by a dimensionless elasto-capillary number.