Surface-Driven Capillary Flow of Aqueous Microparticle Suspensions as Working Liquids in the PMMA Microfluidic Devices

Abstract

Polymethylmethacrylate (PMMA) microfluidic devices have been fabricated by the maskless lithography, hot embossing lithography, drilling and direct bonding technique. The influence of effective viscosity on the speed of surface-driven capillary flow of aqueous microparticle suspensions has been studied. The surface-driven capillary flow of any particular aqueous microparticle suspension is faster in the microchannel of larger channel aspect ratio. Also, the surface-driven suspension flow is faster on the surface of higher wettability. The number densities of suspended polystyrene microparticles in the three individually prepared suspensions are 1×10⁵ particles mL^-1, 1×10⁶ particles mL^-1 and 1×10⁷ particles mL^-1. Dyed water is used as control liquid. This experimental study may be useful to investigate the surface-driven suspension flow in the designed microfluidic lab-on-a-chip systems. 

Keywords: PMMA, Microchannel, Suspension, Capillary flow