Generation of Water-In-Oil-In-Water (W/O/W) Double Emulsions By Microfluidics / 分析化学

ABSTRACT

Novel compartment microparticles produced with double emulsion droplets as templates provide a protected internal space for material encapsulation. The effect of three-phase flow rate on the micro-droplet generation of double emulsion mechanism is available for reference to produce precise size and highly monodisperse particles. The influence of three-phase flow rate on the formation mode and size of the emulsion droplets was mainly investigated by making use of experiment and numerical simulation. The size of compound droplets decreases and the frequency increases with the increasing outer fluid flow rate. The monodispersity of the double emulsion reduces due to transition from dripping to narrowing jetting regime. Outer droplet size increases with the increasing flow rate of the middle fluid, whereas inner droplet size is the opposite. The frequency increases and then stabilizes,which leads to a widening regime. When Q2/Q1>6, multi-core type double emulsion droplets are produced. Droplet coalescence occurs when surfactant is not considered. As Q1 increases,there is an increasing tendency for inner drop size. The outer drop size is proportional to the sum of the inner and middle flow rate,and that is regardless of Q1/Q2. For drop size,ratio of core-shell and internal structure are precisely controlled by adjusting three-phase flow rate respectively.