An extended Maxwell-Wagner theory for the electric birefringence of charged colloids

Recent frequency resolved electric birefringence experiments on dilute susp ensions of charged, ellipsoidal particles reveal new relaxation features in the MHz frequency range. Such behavior can be explained in terms of surfac e transport processes. Here we develop a model for the electric polarizabil ity of spheroidal particles by combining features of electrokinetic and Max well-Wagner theories. The model accurately depicts the high frequency featu res and relates them to the colloidal properties of the polyelectrolyte. Us ing the model, particle charge can be extracted from electric birefringence measurements. (C) 2000 American Institute of Physics. [S0021-9606(00)51040 -X].