title: Controllable preparation of monodisperse O/W and W/O emulsions in the same microfluidic device.
abstract: This letter presents a simple way to prepare monodisperse O/W and W/O emulsions in the same T-junction microfluidic device just by changing the wetting properties of the microchannel wall with different surfactants. Highly uniform droplets ranging from 50 to 400 mum with a polydispersity index (sigma) value of less than 2% were successfully prepared. With the change in surfactants and surfactant concentrations, the interfacial tension and the wetting properties varied, and disordered or ordered two-phase flow patterns could be controllable. Monodisperse O/W and W/O emulsions were prepared under the action of a cross-flowing shear force or a perpendicular shear force by using an oil solution with 0.1-2.0 wt % Span 80 and an aqueous solution with 0.1-2.0 wt % Tween 20 as a continuous-phase flow, respectively. It gives a controllable method of preparing O/W and W/O emulsions in the same microfluidic device.
authors.affiliation: The State Key Lab of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: J H
authors.initials: JH
authors.lastname: Xu
authors.forename: S W
authors.initials: SW
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Tan
authors.forename: Y J
authors.initials: YJ
authors.lastname: Wang
authors.forename: G S
authors.initials: GS
authors.lastname: Luo
mesh_terms: D004655:Emulsions / Q000138:chemical synthesis* / Q000737:chemistry; D046210:Microfluidic Analytical Techniques; D009821:Oils / Q000737:chemistry*; D012212:Rheology; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D004655:Emulsions; D009821:Oils; D014867:Water