Charging mechanism in colloidal particles leading to a linear relation between charge and size
- Ghent University, Electronics and Information Systems, Sint-Pietersnieuwstraat 41, Ghent B-9000 (Belgium)
Colloidal particles that are dissolved in a liquid can become charged by preferential adsorption or dissociation of surface molecules. The assumption of a constant surface charge density leads to a particle charge that is proportional to the square of the radius. Recent experiments however have shown that in a number of cases the charge is linearly proportional to its size. We present a simple model for the charging of colloidal particles leading to a linear relation between charge and size in the framework of the mean-field Poisson-Boltzmann theory. The model is based on preferential adsorption or dissociation of surface molecules, in combination with a large concentration of chargeable surface sites. The model also predicts a surface potential that is independent of the particle size. Numerical simulations show that this model is in good agreement with analytical approximations.
- OSTI ID:
- 21072395
- Journal Information:
- Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 75, Issue 3; Other Information: DOI: 10.1103/PhysRevE.75.031405; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
- Country of Publication:
- United States
- Language:
- English
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