Surface-Driven Capillary Flow of Dyed Ethanol in a Single SU-8 based Microchannel Bend Fabricated on Glass

Abstract

In this experimental work, a single SU-8 based microchannel bend is fabricated on glass by maskless lithography and indirect bonding technique. Dyed ethanol is prepared as working liquid by mixing commercially available food dye with ethanol. Surface-driven capillary flow of dyed ethanol in streamline motion is recorded by a CMOS camera catching 25 frames per second with a corresponding time-scale resolution of 0.04 second. Effect of centrifugal force on surface-driven capillary flow is prominent in the recorded snap shot images. A brief comparative study is made between the SU-8 based microchannel bend of this present work and the polymethylmethacrylate (PMMA) microchannel bends of an earlier published work. Similar effect of centrifugal force is found in the SU-8 based microchannel bend and PMMA microchannel bends. This work will be useful in commercial bioengineering applications.

Keywords: Maskless lithography, SU-8, Microchannel bend, Ethanol, Capillary flow