Study of Functionally Graded Temperature-Sensitive Hydrogel Micro-Valve Considering Fluid-Structure Interactions

Hydrogels are the smart polymeric materials, which undergo large deformation when they are subjected to different physical and chemical stimuli in contact with fluids. These materials can be applied as sensors and actuators for instance in microfluidics in which the fluid-solid interactions have an important effect on its performance. On the other hand, the use of graded materials is also important considering their advantages. In this study, the behavior of a functionally graded temperature sensitive hydrogel micro-valve is investigated through considering the fluid-solid interactions. In this regard, the appropriate numerical tool for finite element modeling of a functionally graded hydrogel micro-valve has been developed that it has been implemented in both non fluid-solid interactions and fluid-solid interactions simulation. The homogeneous cases of the micro-valve have also been considered to distinguish the functionally graded temperature sensitive hydrogel micro-valve effect. The results indicate that the effect of fluid-solid interactions was important and have considerable impact on micro-valve operating parameters particularly its closing temperature and fluid flow rate. Thus, a comprehensive study on hydrogel-based micro-valve has been presented  considering operating parameters such as inlet pressure and cross linking density of hydrogel.