Chemical Processing of SU-8 Photoresist to Record the Surface-Driven Microfluidic Flow of Dyed Working Liquid in the Regime of Fluid Mechanics

Chemical processing of negative photoresist SU-8 is performed to fabricate a set of three individual SU-8 based glass microfluidic devices inside the cleanroom laboratory. The major steps of SU-8 processing are spin coating using a spin coater, soft baking, ultra-violet (UV) exposure, post exposure baking, development by SU-8 developer, and hard baking. The indirect bonding for leakage-free sealing is used during hard baking to fabricate the microfluidic devices. Author has prepared the dyed water to be used as working liquid. Author has used the CMOS camera to record each capillary flow of dyed water. Each fabricated device contains the arrays of square micropillars which are fabricated on the glass bottom wall of device. The filling time of capillary meniscus is lower corresponding to smaller side length of integrated square micropillars due to lower microfluidic friction. Leakage-free surface-driven capillary flow is recorded corresponding to each fabricated device. Nonlinear meniscus profile is recorded in each microfluidic device. The surface-driven microfluidic flow is generated by thermodynamic reasons according to the published literatures. This experimental work may be useful for commercial bioengineering applications in future.