Charge Inversion at High Ionic Strength Studied by Streaming Currents

Frank H. J. van der Heyden, Derek Stein, Koen Besteman, Serge G. Lemay, Cees Dekker
2006 Physical Review Letters  
We report charge inversion, the sign reversal of the effective surface charge in the presence of multivalent counterions, for the biologically relevant regimes of divalent ions and mixtures of monovalent and multivalent ions. Using streaming currents, the pressure-driven transport of countercharges in the diffuse layer, we find that charge inversion occurs in rectangular silica nanochannels at high concentrations of divalent ions. Strong monovalent screening is found to cancel charge inversion,
more » ... l charge inversion, restoring the original surface charge polarity. An analytical model based on ion correlations successfully describes our observations.
doi:10.1103/physrevlett.96.224502 pmid:16803311 fatcat:6nkuztrbvbdfhaipsetbh4ouca