Particle characterization by AC electrokinetic phenomena 2.: Dielectrophoresis of Latex particles measured by dielectrophoretic phase analysis light scattering (DPALS)

Particle polarization in AC fields depends on the temporal and spatial properties of the inducing field and on the dielectric properties of the suspension medium and the particles. In inhomogeneous fields the interaction of the induced dipole moment with the inducing field may give rise to particle translation (dielectrophoresis, DP). The frequency dependence of DP is mediated by the dispersions of different interfacial polarization processes. Consequently, DP spectroscopy yields information on internal particle structures. Common methods microscopically analyze the frequency behavior of the induced motion. Phase analysis light scattering (PALS) is a suitable light scattering method for the registration of extremely slow particle translation. We used PALS to analyze the DP behavior of polystyrene Latex particles in an optical two-electrode chamber. The dielectric particle data obtained are in correspondence to those of the literature. Our method offers statistical significance and computerized operation for dielectric particle spectroscopy. (C) 1999 Elsevier Science B.V. All rights reserved.