Studies On Continuous Preparation Of Janus Nanoparticles Based On A Centrifugal Microfluidic System

Janus polymer nanoparticles have a wide application prospect in catalysis,biochemical analysis,display technique,material assembly.Liquid could be driven in parallel microchannels of micro fluidic chip using centrifugal technology,which would increase the rate of synthesis.In the synthesis methods based on centrifugal microfluidic systems,the reagents needed to be injected into microchannels in advance.Thus continuous sample injection and synthesis could not be achieved,limiting synthesis productivity.In this paper,a centrifugal micro fluidic chip was designed to successively synthesize Janus nanoparticles of poly(lactic-co-glycolic acid)(PLGA)by continuously injecting two sample solutions at the same time in centrifugal rotation process.In chapter 1,the synthetic method and the research progress of Janus nanoparticles were generally summarized firstly,including preparing spherical and dumbbell-shaped Janus nanoparticles by self-assembly,masking and phase separation.Secondly,the applications of centrifugal micro fluidic systems in preparing microparticles were introduced.Then,the property and synthetic method of PLGA nanoparticles and their applications in biochemical analysis and biomedical science were reviewed.Finally,the purpose and design of this work were proposed.In chapter 2,a novel method of continuously preparing Janus nanoparticles was established by combining the centrifugal microfluidic technology with nanoprecipitation.Three-layer centrifugal chips were designed,with the top and bottom layer possessing corresponding array channels,and through holes in the middle layer bringing the solutions in the upper layer into the lower layer.And then the two phase solutions formed parallel flow in outlets of the bottom layer.Two phase solutions were continuously injected into central injection hole respectively,afterward two PLGA solutions were thrown into the reservoir by centrifugal force in the form of drops,and accordingly Janus nanoparticles were deposited following solvent displacement.The factors affecting the size of nanoparticles,such as rotating speed,the size of channel outlets,molecular weight and concentrations of PLGA were investigated.Nanoparticles with spherical and peanut-like structures were prepared by using PLGA with same terminated-groups and different molecular weights.Productivity could be improved by increasing the number of parallel microchannels in chips.In chapter 3,this novel method of continuous preparation of Janus nanoparticles based on the centrifugal microfluidic technique was summarized and prospected.