Capillary Flow in Microchannel With Pillars

Numerical simulation and experimental results of free surface flow in microfluidic channel containing 10 × 15 array of 350 micron circular cross-section pillars is presented here. Passive capillary driven transport of de-ionized (DI) water and isopropyl alcohol is considered in the study. The channel is fabricated from glass microscope slides patterned with SU8 photoresist using an SF 100 maskless lithography system. Subsequently, microscope slide have been adhered with cyanoacrylate adhesive for sealing the device. The pillars are 120 micron deep, with adjacent pillars being separated by 300 micron. The three-dimensional free surface phenomena is simulated by volume of fluid (VOF) technique and microfluidic imaging is used to experimentally visualize the interface movement. This helps in understanding how free surface is modified by the presence of pillars for performing microfluidic analysis. The effectiveness of using pillars in the fluidic channel to enhance capillary flow and create a more uniform wavefront is demonstrated.