Modeling Mass Transport\nDynamics in Deformable Hydrogels\nduring Evaporation

Hydrogels possess exceptional mechanical properties and\nbiocompatibility,\nmaking them widely used in contemporary bioengineering. Specifically,\nin the development of wearable and implantable health monitoring devices\nas well as drug delivery systems, hydrogels are utilized to enable\nprecise control over the transport of solutes. Nonetheless, predicting\nthe distribution of substances within hydrogels still poses a significant\nchallenge due to the complex interplay between the movement of water\ncontent, migration of solutes, and deformability of the hydrogel polymer\nnetwork, which presents challenges to theoretical modeling. Our work\nintroduces a numerical model that addresses the movement of water\nand solute within a flexible hydrogel, accounting for evaporation\nand/or moisture absorption at the boundary. The model solves for water\nsaturation, solute concentration, and hydrogel deformation iteratively\nat each time step while computing the boundary movement velocity based\non the transport process. By comparing the modeled results of geometry\ndeformation and water and solute distributions during evaporation\nwith our experiments, we demonstrate the accuracy and applicability\nof our proposed model. This capability to precisely analyze water\nand solute concentrations in deformable and nonuniform hydrogel environments\npaves the way for advancements in biosensing and drug delivery methods\nthat rely on elastic porous materials.