AC electric-field-induced fluid flow in microelectrode structures: scaling laws

The motion of polarizable bioparticles under the action of non-uniform ac electric fields is known as dielectrophoresis. Because submicrometre particles are subjected to Brownian motion, high electric fields are needed to manipulate them. However, these high electric fields give rise to fluid motion, which in turn results in a viscous drag on the particles. The electric fields generate beat, leading to gradients in conductivity, permittivity, and mass density in the fluid. These gradients give rise to electrothermal forces and buoyancy. Also non-uniform ac electric fields produce forces on the induced charges in the diffuse double layer on the electrodes, that results in fluid motion. Here we characterize these flows and their domain of influence.