Modeling deformation and contacts of pH sensitive hydrogels for microfluidic flow control

Following a recently developed theory for the constrained swelling of pH-sensitive hydrogels and the finite element user-subroutine technique, we modeled deformation and contacts of pH-sensitive hydrogels for real purpose microfluidic flow control systems. A jacket valve consisting of three cylindrical hydrogels coated on three fixed pillars and a hybrid hydrogel/PDMS system are modeled and analyzed in this paper. We present the deformation and multiple contacts of hydrogel based flow control systems when the pH of the external solution is switched to various values. Also included is the pressure in the contacts, stress distribution, sensitivity of swelling ratio with respect to pH values, and in addition the influence of initial fabrication imperfections.