Electrophoresis of Charge Inverted Macroion Complex: Molecular Dynamics Study

"Charge invertsion and mobility of a macroion in the presence of multivalent coions under an external electric field are studied by molecular dynamics simulations. Hydrodynamic interactions are treated with the explicit use of neutral-particle solvent. In a weak electric field, a complex of the macroion with condensed counterions and coions drifts along the electric field, in the direction proving inversion of the charge sign. The electrophoretically determined net charge of the complex is smaller than that of the peak of radial charge distribution, indicating that many co-ions along with counter-ions are involved in the drift. very large electric field disrupts charge inversion stripping the adsorbed counterions off the macroion, which happens at the order of macroion unscreened electric field consistently with the correlation theory of charge inversion