Macroion adsorption: the crucial role of excluded volume and co-ions.
The adsorption of charged colloids (macroions) onto an oppositely charged planar substrate is investigated theoretically. Taking properly into account the finite size of the macroions, unusual behaviors are reported. It is found that the role of the co-ions (the little salt-ions carrying the same sign of charge as that of the substrate) is crucial in understanding the mechanisms involved in the process of macroion adsorption. In particular, the co-ions can accumulate near the substrate's surface and lead to a counterintuitive surface charge amplification.
Messina
René
R
Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany. messina@thphy.uni-duesseldorf.de