Formation of microfluidic droplets in ternary fluid systems

We experimentally examine two-phase flows of immiscible fluids in the presence of a miscible solvent in the dispersed or continuous phase using coaxial microchannels. The role of solvent concentration on flow pattern characteristics and regime transitions is systematically investigated for various injection scheme and over a broad range of flow rates. We show the significant reduction of interfacial tension for flows having a solvent-rich water phase and we study the dynamics of spontaneous emulsification in systems having a solvent-rich oil phase. In particular, we reveal a variety of intriguing microflow behaviors resulting from the interaction of surface tension and diffusion phenomena, including dripping, jetting, dynamic wetting, and tip streaming of microfluidic droplets.