Microfluidic chip emulsification with the cross-junction microchannel is a relatively new technique for preparing water-in-oil and oil-in-water emulsions

as well as the monodisperse microparticles after curing of the emulsion droplets.In the present work

with chitosan

sodium cellulose sulfate(NaCS) and tripolyphosphate(TPP) as raw materials

the chitosan-NaCS/TPP microcapsules were prepared by a cross-flow microfluidic chip.The width and height of microchannel is 200 μm and 1 mm

respectively.Different flow states were observed in the microchannel

and the capillary number Ca was used to identify the laminar

plug and droplet flows to control the formation of microdroplets.The effects of dispersant and chitosan concentration

flow rates of oil phase and water phase on the preparation of microdroplets were investigated.The optimized preparation conditions was 2% chitosan as water phase

liquid paraffin containing 5% Span 85 as oil phase

the flow rate of water phase of 5 μl·min-1 and the ratio of oil phase to water phase at the range of 40—100.The microdroplets of chitosan solution could be obtained with uniform size

and the variation coefficient was less than 0.1.Then the microdroplets of chitosan solution were reacted with the solution of 1% NaCS and 3% TPP

and the chitosan-NaCS/TPP microcapsules with uniform size were obtained.Novel chitosan-NaCS/TPP microcapsules showed a special structure with the double-layer membrane

which have the potential applications as the drug carrier.The results demonstrated that the microfluidic chip could control the size of microdroplets and prepare the monodispersed microcapsules.