Behavior of Photo-thermal Sensitive Polyelectrolyte Hydrogel Micro-valve: Analytical and Numerical Approaches

In this paper, the swelling of the photo-thermal sensitive cylindrical polyelectrolyte hydrogel micro-valve has been studied. For this purpose, a modified constitutive model that considers the polyelectrolyte nature of the photothermal sensitive hydrogels is used. The analytical solution for swelling of the hydrogel cylinder due to temperature and light intensity changes was presented. Then, in order to confront problems with realistic complicated boundary conditions, the finite element (FE) tool was implemented in ABAQUS software by scripting a UHYPER subroutine. Using the FE tool, the swelling of the hydrogel cylinder and contact of the micro-valve with the wall of the channel was investigated. Then, the temperature and the light intensity at which the channel was closed was obtained. Finally, opening valve parameter was studied for analyzing the geometrical influence of the under-study actuator, and the obtained results were discussed.