Dynamics of nonlinear electrophoretic motion of dielectric microparticles in nematic liquid crystal

The dynamics of dielectric microparticles motion in nematic liquid crystal cells with in-plane electrodes was investigated. It was found that the microparticles motion was driven by the Stokes drag and electrophoretic forces in the middle part of the electrodes gap. At low electric field strengths (E < 0.4 V/μm), the electrophoresis of microparticles is linear whereas for E > 0.4 V/μm it has nonlinear nature, due to the induced charges in electric double layers near the microparticles boundary (q~E2). Independently on the NLC alignment, this nonlinearity leads to the cubic dependence of the microparticles velocity on the electric field strength (v~E3). But, the value of nonlinear electrophoretic mobility (μ(3)) of microparticles is a function of the alignment and the parameters of NLC as well as the dielectric permittivity of the microparticles. Near the electrodes, the dielectrophoretic and the elastic trapping forces significantly influence the motion dynamics of microparticles.