Effect of Electrical Field Distortion on Particle-Particle Interaction Under DEP

G. Zhang[1], Y. Zhao[1], J. Hodge[1], J. Brcka[2], J. Faguet[2], E. Lee[2]
[1]Clemson University, Clemson, SC, USA
[2]TEL U.S. Holdings, Inc., U.S. Technology Development Center, Austin, TX, USA

In using DEP for particle manipulation, researchers often use a formula to calculate the DEP forces in which the forces are proportional to the particle radius to the third power. This formula assumes that the electrical field, E, will not be affected by the presence of a particle, no matter what the actual size and the dielectric property of the particle are. This work confirms that the electrical field distortion will occur as the result of differential conductivity and permittivity between the particle and the surrounding medium. This study also provides for the first time a quantitative estimate for the level of the driving forces for such pearl-chain formation.