Ian Wark Research Institute,
University of South Australia, Mawson Lakes SA 5095 Australia.
Current Opinion in Colloid and Interface Science, August, 2001
Abstract
The interaction between charged colloidal particles is mediated by their
electric double layers. Given that pairs of like-charged particles
experience a repulsion, why do some dilute colloidal dispersions become
unstable and condense at low ionic strengths? This puzzling paradox
appears to have been largely resolved over the past year by a careful
analysis of all the contributions to the thermodynamic potential of the
dispersion. The condensation can be predicted using the traditional pair
repulsion of Poisson-Boltzmann theory without invoking any long-range
attractions in the pair potential. However, it has emerged that one has
to go beyond the Poisson-Boltzmann theory to account for the instability
that occurs in confined colloidal dispersions. Other recent advances in
the ubiquitous Poisson-Boltzmann theory have included effective surface
charge approaches in calculating the electrokinetic zeta potential, and
the modelling of charge regulation in colloidal systems.
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