Theory And Experiment Research Of Particles Sorting By AC EO

Recently, considerable interest and effort have been devoted to the on-site detection of low concentration pathogens in water, food and clinical samples in order to deter infectious diseases and bioterrorism. There are many techniques used for manipulating or sorting particles, with a widely used method is electric-based method.Owning to the subjects with lengths of the order micrometer or nanometer, the force arose from electric-based machine is especially for collecting or separating them. With the development of the technology micro-machining in MEMS, it is possible that the microelectrode with the lengths of the order micrometer or nanometer be fabricated into micro-devices. AC EO is a new technology, which shows many advantages in collecting or separating micro-particles, such as low signal voltage, generating bubble not easily, small sample, real-time detection, independent of the size of particles also the grad of electrical field and integrating in microchip easily, so it becomes a hot research subject.This paper introduces the research of particles sorting by AC EO at home and abroad in detail, and the force on the particles is analyzed. The forming principle of AC EO is expounded and the theory of AC EO sorting particles is researched. The numerical value of potential in solution is solved by Green's function method, while the position particles sorting by AC EO is worked out and the formulation is given.The mathematical physics model of AC EO is built on the base of theory. The Laplace equation about electrical and the Navier-Stokes equation about flow field are solved by finite element software. The velocity of particles in micro-channel is solved with considering the DEP and gravity force. The main factors which influence the particles sorting by AC EO, such as frequency, voltage, conductivity of the solution is studied, which provides theoretical basis for experimental research.The parallel symmetry microelectrode chip is designed and manufactured in order to validate correctness of the theories research. The experimental research object is polystyrene of 0.5μmdiameter. The polystyrene sorting by AC EO is seen with florescent microscope when applied AC signal. The experiment of particles sorting with different characteristic parameters is seen successfully by change the application signal, conductivity of the solution, which verifies the tendency influence of the main characteristic parameters to the particles sorting.The full text verifies the relevant theories in this thesis by expounding the basic theory of AC EO particles sorting, theoretical analysis calculation, modeling and simulation analysis and experiment research, which establish the theoretical and experimental basis for further particles sorting and separating by AC EO research.