Simulation Research On Polynomial Electrodes Particle Capture And Manipulation By Dielectrophoresis

With the rapid development of microfluidic technology,the research on micro-scale particles has gradually formed scale in the microworld.It is the foundation of exploring the particle feature and motion law.Dielectrophoresis(DEP)shows great advantages,such as,without fluorescence labeling?high efficiency?easy operation and so on,and it is widely used in particle capture and manipulation.In the researches of particle capture and manipulation,which is based on DEP,the electrode shape?numbers and electrifying modes on the multi-pole electrodes have great effects on the results of capture.Wherein the researches about particle capture that caused by electrode shapes are quite mature and widely used in particle capture,the researches about different numbers of multi-pole electrodes and electrifying modes on electrodes for particle capture are still lack.Hence,this paper,we focuse on the study of particle capture by using polynomial hyperbolic electrodes,analyze the fluid flow characteristics in the microsystem and the machanism of particle capture,simulate and analyze the effects caused by different numbers of electrodes or electrifying modes on particle capture;we design a quadrupole polynomial electrode array to manipulate the particles based on the capture theory.Firstly,according to the fluid flow characteristics of microfluidic chip,we analyze fluid flow situation and equation in the microchannel.We derive microparticle's DEP force and the expression step by step based on the the theory of dipole moment.The effects of electric field frequency and suspension conductivity on the Clausius-Mossotti(CM)factor is simulated and analyzed.Combine with microparticles' s motion state and stress state in the microchannel,the main influence factors of microparticles capture and manipulation are analyzed,we also analyze the particles' motion based on this.The effects of alternating current electrothermal(ACET)on the particles capture are also analyzed.Then,compare the advantages and disadvantages of positive and negative dielectrophoresis,and we select a appropriate way to capture particles;according to the chip's feature;we build the capture and manipulation model by Comsol Mutiphysics,with the example of quadrupole polynomial electrode,we analyze the control equation and set boundary conditions in the model.Respectively,We analyze the distribution of flow field?electric field and temperature field of the models,in order to capture efficiently,the temperature field and thermal field coupling relationship is solved,and the effects of dielectrophoresis and AC electrothermal on particle capture are also analyzed and optimize the parameters of suspension conductivity in the simulation.Afterwards,we design a polynomial electrode array with quadrupole polynomial electrode as a unit of this array,and program the movement of particles in the array,manipulate the particle by changing the weakest rigions in the electrical field.Finally,we build the simulation models based on the shape feature of dipole?sextupole and octupole;and according to the boundary conditions setting in the quadrupole simulation models,the corresponding boundary conditions are set in the new models to get the distribution of flow field?temperature field and electric field.According to the simulation results we analyze the effects of particle capture which is caused by electrode numbers,and discuss the effects of electric field switching in the polynomial electrode models on particle capture.