(236d) Controllable Preparation of Monodispersed Calcium Alginate Microcapsules in a Novel Microfluidic System

In this work, we describe a novel method of prepare monodispersed calcium alginate microcapsules in a microfluidic device. The novel microfluidic device comprised of two cross-junction channels and a synthesizing channel. At the first junction, the side two streams, sodium alginate aqueous solution and calcium chloride aqueous solution, were separated to contact by the injection of de-ionized water in the middle channel. Then the aqueous mixture solution was induced into monodispersed droplets by the crossflow shear of octyl alcohol at the second junction. The formed droplets were in-situ solidified in the synthesizing channel with the rapid mixing of reactants in the droplets. The size of Ca-alginate microcapsules can be controlled from 50 ?Ým to 500 ?Ým in diameter with a variation of less than 5%, simply by changing two-phase flow rates. The results show that for a given fixed dispersed phase flow, the emulsion size decreases as the increase of continuous phase flow rates. The proposed microfluidic platform is capable of generating uniform emulsions and has the advantages of in-situ solidification and well control of size.

Key words: calcium alginate; microcapsule; monodispersed; microfluidic device