Attractive Interaction between Similarly Charged Colloidal Particles

✍ Scribed by Xiaolin Chu; Darsh T. Wasan

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 231 KB
• Volume: 184
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0620

✦ Synopsis

the particle diameter. k 1 is the ionic strength excluding the The pair interactions between the charged colloidal particles contribution by the large colloidal particles, defined as dispersed in a solvent are studied theoretically by the integral equation method. The pair potential of the mean forces, accounting for the effective pair interaction between colloidal particles, is

calculated from the solution of the Ornstein-Zernike equation with the mean spherical approximation (MSA). An attractive interaction was found between two similarly charged colloidal partiwhere r i and Z i are densities and valences of counterions cles in contrast with the purely repulsive force predicted by the and other ions (electrolyte or impurities), respectively. It is Debye-Huckel theory. Such an attractive interaction provides obvious that this potential is purely repulsive. The van der physical insight for the ''condensed'' phenomena in charged colloi-Waals part is expected to provide the attractive force. Hadal dispersions, that is, the coexistence of a ''condensed'' phase maker (6) derived the expression for van der Waals force and an ''expanded'' phase (voids). At the higher concentration between two spherical colloidal particles. In the case of two and charge on colloidal particles, the effective pair interaction particles that are of the same size, it reads becomes oscillatory.