COLL 454 |
| Oksana Shramko, Department of Native Disperse Systems, Department of Native Disperse Systems, Institute of Biocolloidal Chemistry, Ukrainian Academy of Sciences, Vernadsky Blvd. 42, 03142 Kyiv, Ukraine |
| The polarization of the electric double layer (EDL) of colloid particle in electrolyte solution has been attendant by variations of the electrolyte concentration (so-called concentration polarization of the electric double layer). The action of the applied electric field on the field-induced variations of the ion concentrations causes the field-induced ionic charge distribution of the second power with respect to applied field strength. The space distribution of this, quadratic by applied field, field-induced ionic charge in the electrolyte solution adjoined to the particle, corresponds the tendency to the increasing of the co-ions concentration and the decreasing of the counter-ions concentration along the beam, coinciding with the field direction. The interaction of this field-induced charge distribution with equilibrium surface charge contributes to the orientation of non-spherical particles, and, hence, to the electrooptic effect. This new contribution (which may be named “the contribution of non-linear polarization”), as it is clear from the above explanation, has the same (second) order on the strength of the weak applied field as another well-known contributions (from permanent and from induced dipole moments). The quantitative comparison of the contributions of non-linear polarization to that of induced dipole moment for low-frequency limit of the electrooptic effect was made as a function of Z-potential, of dimensionless thickness of EDL, and of a ratio ”particle dielectric permmittivity/media dielectric permmittivity”. |
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ACS Award in Colloid and Surface Chemistry Symposium Honoring Clay Radke
Division of Colloid and Surface Chemistry |