Electrokinetic properties of colloids of variable charge. III. Observation of a Maxwell–Wagner relaxation mechanism by high-frequency electric-birefringence spectroscopy

Frequency resolved electric birefringence measurements were made on dilute aqueous suspensions of charged, rodlike latex particles. Ionic amphiphile adsorption was used to vary the particle charge as described in the first paper of this series [J. Chem. Phys. 103, 8228 (1995)]. Using the high frequency part of the birefringence spectra, the electric polarizability is computed from the Kerr constant following the approach set out in the second paper of the series [J. Chem. Phys. 109, 6905 (1998)]. Then, the polarizability spectra were interpreted with our extended Maxwell–Wagner model [J. Chem. Phys. 113, 6974 (2000), preceding paper]. Theory and experiment are in good agreement. The procedure provides a new and simple way to extract the particle charge from birefringence data.