Comparison of step and flow-focusing emulsification methods for water-in-oil monodisperse drops in microfluidic chips

Abstract

Emulsions are widely used in various disciplines such as food, chemistry, and pharmaceuticals, due to their efficient encapsulation properties. Recently, the emulsion was emerged as a unique tool for fabrication of multi-complex microparticles, which used as drug delivery agents, as effective manipulators for sorting proteins, DNA, and etc. The high productivity of stable monodisperse emulsions formation is of great importance for these aims. Here, the step and the flow-focusing methods for water-in-oil drops formation in microfluidic chips were compared as a tool for generating well-defined and monodispersed drops using mineral oil as a continuous phase. As a result, drops diameter compares with aperture (nozzle) dimensions for the flow-focusing generator and their diameter is much higher for the step design. Monodispersion and productivity for the step-chip strongly depend on phase densities difference. Flow-focusing method is more suitable for fabrication of monodispersed microparticles and step method for rough technologies such as investigating in food industry or cosmetics.