273482 Accurate Predictions of Dielectrophoretic Force and Torque On Many Particles with Strong Mutual Field, Particle, and Wall Interactions

Tuesday, October 30, 2012: 2:06 PM
Fayette (Westin )
Qianlong Liu, Univ. South Carolina, Columbia, SC and Kenneth Reifsnider, Univ. South Carolina

The basis of dielectrophoresis (DEP) is the prediction of the force and torque on particles. The classical approach to the prediction is based on the effective moment method, which, however, is an approximate approach, assumes infinitesimal particles, and totally neglects the perturbation of the resultant electric field by the particles. Therefore, it is well-known that for finite-sized particles, the DEP approximation is inaccurate as the mutual field-particle, particle-particle, particle-wall interactions become strong, a situation presently attracting extensive research for practical significant applications. In the present paper, we provide accurate calculations of the force and torque on the particles from first principles, by directly resolving the local geometry and properties and accurately accounting for the mutual interactions for finite-sized particles with both dielectric polarization and conduction in a sinusoidally steady-state electric field. Since the approach has a significant advantage, compared to other numerical methods, to efficiently simulate many closely packed particles (one million 2D particles and one hundred thousand 3D particles), it provide an important, unique, and accurate technique to investigate complex DEP phenomena, for example heterogeneous mixtures containing particle chains, nanoparticle assembly, multilayered materials, non-spherical effects, etc.

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