Polarization interaction of disperse particles with not thin Debye atmosphere

The electric field of the equilibrium double layer acts only at the distance of the Debye length. Therefore, the distances at which the electrostatic interaction forces act between particles in the absence of external fields are limited by the same length. As shown previously, the external electric field results in the appearance of volume charges outside DL. As a result, the long-range acting electric forces appear. In addition, the forces become anisotropic. The polarization forces are proportional to at least the square of the external field. Previously we had shown that quadratic forces occurred not only as a result of the interaction of the charges being linear to an external held, but as a result of the interaction between the charges being quadratic to an external field as well as the equilibrium charges. We have described these quadratic charges in the theory of the double layer nonlinear polarization without any restrictions on the double layer thickness. This theory was developed by the method of successive approximations on the extemal field and the electrokinetic sigma-potential. These results are obtained in analytical form and agree with the Fixman and Jagannathan's 1983.numerical solutions. Our calculations of the polarization interaction energy showed: (a) in suspension of polar nonconductive particles in the less polar medium the orientation of the duplet perpendicular to field is more advantageous than along the field; (b) the attraction of the charged polar particles is substituted by the repulsion with the particle sigma-potential increase both for longitude duplet (sigma=2.5 mV) and for transverse duplet (sigma=1.5 mV); (c) with the polar medium conductivity growth the repulsion forces between particles of the longitude duplet are changed by the attraction forces. (C) 1998 Elsevier Science B.V. All rights reserved.