Effect of microchannel geometry in fluid flow for PDMS based device

Microfluidic has become an important component in “lab on chip” device. This portable device has a lot of potential in medical diagnostic to inform the result spontaneously to the patient with only a small volume of sample and reagent. The device's fabrication using Polydimethylsiloxane has become conventional materials which use soft lithography technique developed by Whitesides. However, the inconvenience from this method is the channel fabricated will have a rectangular cross section. From macroscale perspectives, we suggest that circular shape is the best choice to obtain a better performance from the device even though the fabrication of circular microchannel is still a huge obstacle to be figured out. In this paper, we present a fluid flow simulation using finite element COMSOL module microfluidic for circular and rectangular microchannel. Through this simulation, we can see the impact of microchannel shape through the difference in pressure along with velocity and shear rate. From the simulation, the data provided show that a circular channel reduce almost 10 % of the pressure applied to flow the fluid but also 50% of the shear rate. The future work of this study is to fabricate a simple and low cost round microchannel and integrate it in the next lab on chip device.