the basis of the boundary conditions specified. For an arbi-The electrostatic interaction between two ion-penetrable, charged trary geometry and boundary conditions, this is not an easy spheroidal particles is examined theoretically. These particles can task. Reported results for two interacting charged entities in assume different sizes and an arbitrary spatial orientation. The an electrolyte solution are limited in the literature. Ohshima electrical potential distribution is derived analytically under the and Kondo (2) considered the electrical interactions between Debye-Huckle condition. The results for two interaction spheres, two charged, ion-penetrable spheres. They showed that if one spheroidal particle and a planar surface, and rigid particles the fixed charges in the spheres are distributed homogecovered by an ion-penetrable membrane can be recovered as the neously, both the electrical potential distribution and the special cases of the present general problem. We show that, for a interaction energy can be derived analytically. The analysis fixed center-to-center distance between two particles, regardless of their relative sizes, the interaction free energy is the greatest if their was also extended to the case of an ion-penetrable sphere major axes lie on the same line ( head-to-head), and the smallest if and a rigid surface (3). An image method was adopted their major axes are perpendicular to each other but not on the which applies the result for the case of two ion-penetrable same plane (perpendicular). แญง 1997 Academic Press spheres. Some other results for two spherical particles in-Key Words: electrostatic interaction, free energy; particles, spheclude Ohshima (4-8), Ohshima and Kondo (9), Krozel and roidal, ion-penetrable; electrical potential distribution, analytical Saville (10), and Sengupta and Papadopoulos (11). Allain expression.
and Cloitre (12) examined the interaction between two parallel cylinders. The electrical interaction between two twodimensional inclined platy particles was discussed by Anan-