Computational Study of Separation of Size-Specific Microparticles Using Dielectrophoresis

• Main Authors: Jah-Ming Lai, 賴志銘
• Other Authors: Andrew M. Wo
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/52459934449387353981

碩士 === 國立臺灣大學 === 應用力學研究所 === 95 === This thesis presents the computation of separation of size-specific particles using dielectrophoresis (DEP) in a microfluidic device. The goal of the study is to separate heterogeneous population of particles into bins downstream. Different configurations of electrodes are designed, such as gradual, step, and deterministic, in order to achieve non-uniform electric field strength. Particles of diameters 5μm, 10μm, 15μm, and 20μm are used. Parameters of the Clausius-Mossotti (CM) factor were determined to achieve negative dielectrophoresis (nDEP) at the range of specified frequencies. The relations between negative dielectrophoretic force (nDEP) and drag force are used to derive the governing equation of particle trajectories. An overarching parameter, called sorting factor, was derived to account for the force balance on the particle and it also serves to compare performance among the three electrode designs. Results of computation showed that size-specific particles could be separated at the frequency above 600Hz by using gradual and step electrode designs. As a whole, the sorting factor serves well to correlate the efficacy of separation in most cases studies. According to sorting factor analysis, if the input A.C. signals increases, the range of the flow velocity also increases which is an important consideration for this device. Furthermore, the suitable input A.C. signals are chosen for this experiment. However, the deterministic electrodes of these devices may separate particles of 10μm, 15μm, and 20μm in diameters and particles of 5μm and 10μm in diameters. For the moment of the result of computation, the deterministic electrode of this device may not completely separate size-specific bioparticles.