Eur. Phys. J. E 4, 363-370
Effect of colloidal charge discretization in the primitive model
R. Messina, C. Holm and K. KremerMax-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany messina@mpip-mainz.mpg.de
(Received 30 June 2000 and Received in final form 28 November 2000)
Abstract
The effect of fixed discrete colloidal charges in the primitive model is investigated
for spherical macroions. Instead of considering a central bare charge, as it
is traditionally done, we distribute discrete charges randomly on the
sphere. We use molecular dynamics simulations to study this effect on various
properties such as overcharging, counterion distribution and diffusion. In the
vicinity of the colloid surface the electrostatic potential may considerably
differ from the one obtained with a central charge. In the strong Coulomb coupling,
we showed that the colloidal charge discretization qualitatively influences
the counterion distribution and leads to a strong colloidal charge-counterion
pair association. However, we found that charge inversion still persists
even if strong pair association is observed.
82.70.Dd - Disperse systems: Colloids.
61.20.Qg - Structure of associated liquids: electrolytes, molten salts, etc..
41.20.-q - Applied classical electromagnetism.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
