Colloidal particle aggregates induced by particle surface charge heterogeneity

Interaction of charged particles, induced by adding an oppositely charged polyion, gives rise to intriguing aggregation phenomena. The presence of short-range interactions in competition with electrostatic repulsions results, in an interval of concentrations around the inversion point, in the formations of long-lived clusters of polyelectrolyte-decorated particles. We will show that the whole aggregation scenario can be justified as due to an heterogeneous charge distribution at the particle surface, as a consequence of the correlated polyion adsorption, on the basis of a recently model proposed by D. Velegol, R Thwar, Langmuir 17 (2001) 7687-7693. (C) 2009 Elsevier B.V. All rights reserved.