Study of different membrane shapes for integrated pneumatically actuated microvalves with PDMS

Abstract

Fabrication of Microfluidic devices have gained popularity in a wide range of application demanding fluid flow control such as Anti-microbial resistance, Integrated blood test systems, drug delivery system, protein separation, DNA extraction, in- vitro diagnostic studies, lab-on-a-chip, organ-on-a-chip, inkjet printers and other industrial sensors. Fluid flow regulation, on/off switching and sealing of fluids can be achieved by incorporating Microvalves. The shape of the microvalve plays a key role in desired actuation of the microvalves. Therefore, a detailed study of various structures of the microvalve is crucial. This work discusses about the stability and reliability of different microvalve shapes. Simulation work gives a comparative study showcasing the displacement of the microvalve thin film polymer layer on account of applied pressure on several shapes of same area. Furthermore, details of stress distribution for the same has been carried out. The analysis focusses on the circular, elliptical and capsule shapes of the microvalve. The comparative study of the simulation results revealed that the maximum stress experienced by the microvalves of circular shape is 1.1 times lower than that of elliptical shape. While, circular shape microvalve shows 1.22 times lower stress when compared to capsule shape. In addition, displacement of the circular shape microvalve is 1.33 and 1.31 times greater than elliptical and capsule shapes for the same area and applied pressure respectively. The study manifests that the circular shape microvalve performance indicate better stable actuation when compared to the rest of the shapes. Microfabrication of the same is carried out using dry film photoresist which is highly cost effective.