Dielectrophoretic and electrophoretic force analysis of colloidal fullerenes in a nematic liquid-crystal medium

Received 5 June 2009; revised manuscript received 27 August 2009; published 16 November 2009This research focuses on the electrokinetic motion of fullerenes suspended in liquid crystal host medium,which are investigated in the homogeneously aligned nematic liquid crystal cells driven by in-plane field. Weinvestigated the effect of electrophoretic and dielectrophoretic forces and related parameters of the colloidalfullerenes in liquid crystals. The electrophoretic mobility, zeta potential, and critical voltage have been evalu-ated. Fullerenes suspended in liquid crystal medium migrated toward the positive electrode, but were pulledback in the opposite direction when the polarity was reversed especially at low frequency range 5Hz .Athigher electric field and higher frequency ranges, the net displacement of fullerenes has been observed. Wedemonstrate that the dielectrophoretic force dominated the motion in the colloidal fullerenes by a properanalysis of different electrophoretic parameters. In addition, the electrodynamics of fullerenes was explainedby applying the theory of the dielectrophoresis and Schwarz’s formula. We propose a model to estimate thedensity of fullerenes suspended in liquid crystal medium.DOI: 10.1103/PhysRevE.80.051702 PACS number s : 83.80.Xz, 82.70. y, 47.57.jd, 87.15.Tt