Key Technology Research On Droplet Formation And Manipulation In Droplet Microfluidics

Drops are prevalent in nature and our daily life,such as the drops drip from shower and taps and the drops that remains on the lotus leaves after raining.Using these micro-droplets to replace the beakers and reaction cups in traditional biochemistry laboratory,make chemical reaction and biomedical detection to be microscale,may be help for decreasing reaction reagent,shorten the reaction time,adjusting local react condition,increasing reaction precision and so on,it has show great potential in a large amount of application.For that,mass product micro-scale and controllable droplets is necessary.Droplet-based microfluidics is a science technology that product and control micro-droplets,it can product thousands microdroplets which with uniform scale and controllable every minute,each microdroplet can be independent reactor because of the separation of oil phase,compared with the other traditional biochemical reaction system,Droplet-based microfluidics has apparent advantages such as high-throughput,low cost,no cross contamination and save manufacturing cost and time and so on.Micro-droplets have great potential in application,however in order to make it play a role,the first thing is fabricate controllable micro-droplets which with uniform scales and precise structure steadily.Therefore,produce stable and controllable micro-droplets in high frequency,control the micro-droplets precisely and high-throughput in produce is the key step which to come true it`s application value.In this context,this paper analyzed the theory about the micro-droplets' formation and micro-droplets' manipulation,meanwhile based on the theoretical analysis,mastered the technology of micro-droplets' formation and manipulation,and make innovative improvements at the technical level,sets up a solid foundation for the related application of droplet-based microfluidics and micro-droplets.concrete content as following:1.This paper introduced the background and research status and abroad of microdroplets' formation and manipulation.Briefly described the basic mechanism for the two-phase flow and analyzed the influence about non-dimensional parameters in micro-droplet dynamics.The droplet formation mechanisms for T shape microchannel,stream focusing,and coaxial fluids are described,meanwhile the basic manipulation mechanisms are analyzed.The interrelation among main parameters was established and gained the general regulation about that.2.This paper use glass capillary microfluidics device and Polydimethylsiloxane microfluidics device to study the formation and manipulation of micro-droplets in microfluidics.Conduct an experiment on formatting micro-droplets by using liquid with different fluid properties,obtained the quantitative relation which impact the formation of micro-droplets and the scales of micro-droplets,such as we can obtain the relation between the scale of microdroplets and the two-phase flow ratio by velocity ratio.3.Applied electric field in microfluidics at the technical level,study the effect of electric field on the formation and size distribution of micro-droplets,increase shear force to obtain smaller micro-droplets by using electric field so that break through the minimum size of microdroplets which produced by microfluidics.4.This paper choose non-Newtonian fluid which represents typical biological fluid and has complex rheological property,and preliminary studied the formation and manipulation of non-Newtonian fluid micro-droplets,found the different phenomenon with Newtonian fluid in micro-droplets formation,and has done an initial analysis.