Charge inversion at high ionic strength studied by streaming currents.
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, restoring the original surface charge polarity. An analytical model based on ion correlations successfully describes our observations.
van der Heyden
Frank H J
FH
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Stein
Derek
D
Besteman
Koen
K
Lemay
Serge G
SG
Dekker
Cees
C
D007473:Ion Channels / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D009994:Osmolar Concentration; D012822:Silicon Dioxide / Q000737:chemistry
D007473:Ion Channels; D007477:Ions; D012822:Silicon Dioxide