ELECTROOPTIC INVESTIGATION OF OXIDE SUSPENSIONS - MECHANISM OF FORMATION OF THE INDUCED DIPOLE-MOMENT

A model system (aqueous suspension of aluminium oxide particles) is used for the investigation of the mechaism of formation of the induced dipole moment, causing the large low-frequency electro-optic effects exhibited by colloid suspensions. The results demonstrate that the induced moment in the kilohertz frequency region is created only by the diffuse part of the surface electric double layer. The relaxation frequency of the induced moment shows a distinct dependence on the diffuse layer charge density. A surface conductivity mechanism is in accordance with the presented results. © 1991.