Hydrogel swelling in confined geometries

Hydrogels are hydrophilic polymer networks capable of absorbing up to 10³ times their dry weight in water. Thus, they provide a nonliving material that can be used to study the interplay between volumetric growth and geometric constraints. Recent experiments in granular media reveal that hydrogels that must pass through narrow pores in order to expand show surprising fracturing behavior. In order to better understand what gives rise to these fractures, we simulate the swelling of a hydrogel through a pore using a thermodynamically consistent model that takes into account the transport of water and large deformations of the hydrogel. We explore the spatiotemporal distribution of stresses as a function of material properties and pore geometry, and comment on conditions that may lead to fracture.