ABSTRACT
Transient electric birefringence measurements were carried out on dispersions of saponite, a synthetic clay mineral, in order to obtain new information about the anomalous Kerr effect. The anomalous signal in the semidilute concentration region was also studied as a function of amphiphilic polymers that adsorb on the clay particles. For transient measurements with the single-pulse method the anomaly disappeared and, on saturation of the clays with adsorbed polymers, a single exponential signal is observed that is due to the alignment of the particles parallel to the electric field. The anomalous transient electric birefringence signals from dilute and semidilute clay dispersions are the result of a superposition of two separate signals, one that is caused from an induced electric dipole and the other that is caused from an apparently permanent dipole. In dilute solutions, the negative signal is smaller than the positive one and is therefore not visible in the total signal if the transient method is used.
