Effects of channel and operation parameters on emulsion production using oblong straight-through microchannels

Abstract

Straight-through microchannel (MC) arrays consisting of numerous oblong straight-through holes are promising MC emulsification devices for producing monodisperse emulsions in large droplet-production scales. We investigated the effects of MC dimensions and velocity of a cross-flowing continuous phase on the production of soybean oil-in-water emulsions using straight-through MC arrays made of single-crystal silicon. The aspect ratio of oblong MCs with equivalent diameters of 21 μm to 22 μm significantly affected droplet generation and the sensitivity of droplet size to continuous-phase velocity. Uniform oil droplets with diameters of about 100 μm and coefficients of variation of less than 3% were generated using large oblong MCs with equivalent diameters of 54 μm to 55 μm. Data analysis demonstrated that oblong MCs with aspect ratios exceeding a threshold of 3 were necessary to generate uniform oil droplets in a wide range of MC cross-sectional sizes. Moreover, the cross-flow of the continuous phase did not affect the size of the droplets generated using oblong MCs with a large aspect ratio.