Study On The Spherical Particle’s Velocity Driven By Dielelctrophoresis And Its Influencing Factors

Dielectrophoresis(DEP) generated by the AC electric field is one of themost important technologies to realize the precise control of particles in thesolution. It could realize particles’ location, separation, enrichment, seizing andtranslation. The calculation of DEP velocity is still a puzzle in the DEP basicresearch. The study of how to analyse and make use of the influence factors toimprove the efficiency of DEP has significance for precisely control of particlesin microfluidics.This paper whit the speed of particles driven by DEP as the main researchcontest, analysed the mechanism of DEP, deduced the DEP velocity formula ofthe spherical particles and analysed its influence factors. And acquired that thedistribution of▽|E|~2is the most important factor for the DEP velocity’sdistribution. Then, studied on the simulation and experiments about the structureof the flow passage and obtained the uniform distribution flow structureThe first part mainly summarized the common research of the particlemanipulation method at present and the research status of dielectrophoresisvelocity. Then reviled the mechanisms of DEP, deduced its stress formula. Withthe polystyrene microspheres as an example, the forces of spherical particleswere analysed at the DEP’s condition, and its velocity formula was acquired.Then analysed the influencing factors of DEP velocity and provided its variationof the conductivity and relative dielectric constant of the solution, voltage andfrequency of the electric field. And it acquired the conclusion that thedistribution of▽|E|~2in the chip is the most important factor for DEP velocity.These provided a theoretical basis for the following simulations and experiments.Based on the theoretical analysis of DEP velocity,3D electrostatic fieldsimulation model was established and the relevant control equations andboundary conditions were set up. It acquired the electric field and velocitydistribution for several structures commonly used. And based on this, thedesired flow passage for particle speed control was designed. And it gave therelationship of DEP velocity and voltages of the electric field.The microfluidic chips based on the hyperbolic electrodes were designed tochecking the validity of theory analyzing and simulation investigation. And one of the chips was equipped with photoresist flow passage. The DEP contrastexperiments were done with the two microfluidic chips and observed itsphenomenon under the condition of different parameters via the microscope.Then measured the particles’ velocities by particle image velocimetry, acquiredthe relation curves between the DEP velocity and some relevant parameters.Those proved exactness of the theoretical and simulation study and confirmedthe availability of the channel.