Microfluidic behavior of ternary mixed solutions of water/acetonitrile/ethyl acetate through experiments and computer simulations.

When ternary mixed solutions of water/acetonitrile/ethyl acetate are delivered into a microspace under laminar flow conditions, the solvent molecules show specific microfluidic flows, such as microfluidic inverted flow and tube radial distribution flow, which have been applied to novel analytical methods. In this paper, inverted flow was examined using various Y-type microchannels that had mixing angles of 0°, 90°, 180°, and 270°. Inverted flow was experimentally observed and the trigger phenomenon was also successfully expressed through computer simulations. Tube radial distribution flow, that is, annular flow, in a capillary tube is reported to cause exchange of the inner and outer phases based on the solvent composition of the ternary mixed solution. Tube radial distribution flow for an organic solvent-rich inner and a water-rich outer phases, as well as for a water-rich inner and an organic solvent-rich outer phases, could be well recreated by computer simulations for a ternary mixed solution. This highlights the effectiveness of computer simulations for such flow scenarios and will allow optimization of the operating conditions and design of microfluidic analytical devices.