Increasing the poroelastic diffusion coefficient in hydrogels

Hydrogel-based atmospheric water harvesting systems have gained popularity in recent years due to the increasing global water scarcity. In such applications, the speed of water transport can dictate water harvesting performance. As such, it is important to understand how liquids permeate through hydrogels. Hydrogels are soft and swellable polymeric networks where water transport is described by the poroelastic diffusion coefficient—a combined permeability-stiffness property of hydrogels. Our study uncovers a simple scaling relationship between the hydraulic permeability and mechanical stiffness of hydrogels that applies to hydrogels that differ only by crosslinking. Through the prefactors of the scaling relationship, we provide insight on how to improve the poroelastic diffusion coefficient, paving the way for improved gels for water harvesting.