Nonlinear effects in the stability of highly charged colloidal suspensions.

We investigate the nonlinear effects related to the formation of particle-counterion clusters in highly charged asymmetric colloidal suspensions. The ocurrence of such clustering is experimentally probed by studying the stability of the colloidal system. The results demonstrate that a renormalized charge is needed in order to explain the observed critical coagulation concentrations. This renormalization is predicted by an extension of the Debye-Huckel-Bjerrum liquid state theory [A. Diehl, M. C. Barbosa, and Y. Levin, Europhys. Lett. 53, 86 (2001)]. Therefore, counterion condensation seems to become apparent in particle aggregation processes through control of the repulsive barrier that keeps the system stable. As a consequence of the agreement, new insights into the microscopic state of highly charged complex fluids follow.