Synthesis Of Polymer Microcapsules Based On Microchannel Droplet Flow Technology

The microcapsules with core-shell structure have many advantages including concealing the physical properties and shapes of the core material,isolating the core material from the environment,reducing the toxicity of the core material,masking the bad taste,and have important applications in various industries such as food,textile,medicine,paint and cosmetics.Therefore,it has great significance for the practical application of microcapsules to study the preparation of microcapsules by microfluidic droplet technology.In this paper,the microfluidic platform for preparation of microcapsules was built with simple materials.The flow state and droplet formation dynamics of the fluid in the microfluidic chip were studied.The influence of continuous phase flow rate,dispersed phase flow rate and fluid viscosity in the microchannel on the droplets size were systematically explored.The microcapsuled phase change materials are prepared by microfluidic chip.The effects of fluid state and cross-linking degree of wall materials on the function of microcapsules are systematically studied.The results of electron microscopy show that the microcapsules have round shape and good monodispersity.The particle size of microcapsules is uniform and can be controlled in the range of 100-800 ?m.DSC and thermogravimetric results show that the microcapsules have excellent phase change performance,which is up to 200 J/g.The encapsulation efficiency and thermal stability temperature of microcapsules are 78% and 175 °C,respectively.What's more,it is found that the higher degree the monomers link,the better performance the obtained microcapsules have.The wrinked microcapsules are prepared by microfluidic chip,and the influence of the fluid state in the microchannel on the shape of the microcapsules is systematically studied.Microscopy results show that the microcapsules have good monodispersity and microcapsules size is uniform and can be regulated in the range of 400-800 ?m.The monomer concentration,two-phase flow rate and the viscosity of the fluid in the microchannel have an effect on the microcapsule wrinkles.At the same time,the complicated microcapsules with double-layer can also be prepared by taking advantage of the wrinkles and permeability of the membrane,which lays a foundation for the preparation of microcapsuled phase change materials containing both water-soluble and oil-soluble phase change materials.