Hydrodynamics of aqueous two-phase systems (ATPS) in millichannels

Liquid-liquid segmented flows in microchannels have been extensively investigated the context of nanoparticle synthesis. The enhanced mixing slugs results monodispersed particles. Earlier studies focused on Organic-Aqueous Systems (OAS). nanoparticles synthesized presence organic solutions limited applications. An alternative green route for synthesis can be developed using an Aqueous Two-Phase System (ATPS). These systems are characterized by interfacial tensions, which two orders magnitude lower than typical aqueous systems. In this work, flow patterns and hydrodynamics ATPS as a first step. Polyethylene glycol -trisodium citrate system was chosen ATPS. objective work is to see if any new physics arises system. low tension high Capillary numbers (Ca >> 3) microfluidic Consequently, observed here parallel or core-annular. However, millichannel, capillary number becomes << 1) experiments were carried out millichannel span different patterns. pattern formation analyzed classified into three categories, i.e., slug (interfacial dominated), transition flow, core annular (inertia dominated). Flow regime maps based Reynolds number, Weber each phase found qualitatively similar those OAS. Simulations performed various values. value 1.25x10-4 N/m yield sizes fitted well with experimental data. Film thickness measured experimentally simulations compared favorably correlations available literature