Mathematical modeling and simulation of dissolvable hydrogels

Hydrogels have a large number of potential applications in microelectromechanical technology as sensors and actuators. In this paper we try to understand the physics of dissolvable hydrogels and investigate the various parameters controlling the dissolution process. Hydrogels, crosslinked via disulfide bonds, when immersed in a solution containing the disulfide cleaving agent can break covalent cross links causing the hydrogel to dissolve and thereby indicating the presence of the cleaving agent. Such a concept can be used to develop biochemical sensors, sacrificial structures in microfluidic systems, and other applications. The mechanism of the hydrogel dissolution process has been studied in detail and a mathematical model has been developed. From the vanishing time of the dissolvable hydrogel, a significant amount of qualitative and quantitative information about the solution can be obtained. A large number of factors governing the hydrogel dissolution process were investigated by simulations and experiments.