Research On The Process Parameters Of Thermocompression Bonding And Droplet Generation Of Polymer Microfluidic Chip

Entering the 21 st century,the "chip laboratory",that is,the microfluidic technology,which aims to achieve rapid,integrated,miniaturized and low consumption of biochemical analysis,is also on the path of rapid development.Microfluidic chip,as its technology carriers,has also gained more and more attention.Polymer materials are increasingly becoming ideal materials for microfluidic chip due to their low cost,ease of mass production and good optical performance.The thermocompression bonding technology applied to polymer microfluidic chip,because of its simple equipment requirements and wide range of applicable materials,can also further promote the enterprises to achieve efficient mass production of microfluidic chip.In order to reduce the cost of polymer microfluidic chip and help companies achieve mass manufacturing.This thesis researches the thermocompression bonding technology of polymer microfluidic chip,focusing on the thermocompression bonding process parameters(the control of bonding temperature,pressure and time),to explore the impact of chip bonding quality.Through the Multiphysics simulation software COMSOL Multiphysics,a cycloolefin copolymer material microfluidic chip with micron-level microchannel structure is taken as the research object and simplified.According to the theory of thermocompression,the coupling simulation is carried out near the glass transition temperature of the material,and the influence of various process parameters on the deformation of the microchannel inside the chip is analyzed to provide guidance for practical experiments.Combining single-factor control variables and multi-factor multi-level orthogonal simulation experiments,the results show that: the bonding temperature has the greatest influence on the microchannel deformation of the microfluidic chip,followed by bonding pressure and bonding time.In order to control the degree of deformation of the chip microchannel size during thermocompression bonding within 5%,the bonding pressure can be controlled between 0.15?0.30 MPa,the bonding temperature between 75?80?,and the bonding time is selected as 240 s.At the same time,the corresponding thermocompression bonding experiment and droplet generation experiment were carried out.Under a set of experimental platform including thermocompression bonding,droplet generation,observation and detection equipment,microfluidic chip semi-finished products made of cycloolefin resin TOPAS? materials are used to complete the corresponding experiments,in order to verify the chip size before and after thermocompression bonding,and verify its performance(chip bonding strength and droplet generation index).The experimental results show that: when the controlled variable test which is carried out near the referenced process parameters,the bonding temperature has the greatest influence on the chip microchannel deformation;and the bonding pressure and bonding time exist optimal solutions in a certain range considering the strength requirement of bonding.For the microfluidic chip to meet the technical indicators of stable generation of droplets with a diameter of 70?m and good uniformity,after studying the relationship between the resistance of the fluid in the formation of droplets and the structure of the microchannel,the theoretical driving pressure range of oil and water phase is calculated by using the loss theory.Cooperate with the computer image processing means to conduct image shooting,size measurement and uniformity analysis of the droplets generated under the driving pressure range.Multiphysics simulation and a series of experiments indicate that the correct thermocompression coupling simulation analysis can play a good role in predicting the actual microfluidic chip bonding process;and the feasibility of the droplet generation scheme can also provide guidance for production applications.