Micro-valves play an important role in controlling and operating microfluidic systems. Utilizing stimuli-sensitive hydrogels facilitates the construction of smart micro-valves controlled by temperature, concentration (salt, organic solvent) or pH level.
We propose a finite element model which uses the thermal domain as an auxiliary domain for the volume change response of hydrogels. Behaviors like local displacements within the hydrogel are difficult to measure, but can be reproduced with finite elements. For the application of the micro-valve, the hydrogel model is connected to the fluid domain. The hydrogel is placed directly into the fluid flow and opens or closes the flow path. For this, a full iterative cycle with material properties and remeshing in each simulation step is implemented in ANSYS®.
This model concept and the results will help to better understand, predict and visualize the behavior of hydrogels and support the development of highly integrated hydrogel-based microfluidic circuits.
