Summary: 2
Abstract.
Phil Attard
Introduction
Ion condensation in the electric double layer and the corresponding
Poisson­Boltzmann effective surface charge
The effective surface charge obtained by fitting
the Poisson­Boltzmann approximation to measured data is re­
lated to the actual surface charge. Evaluation of the formally
exact expression, which depends upon the wall­ion direct cor­
relation function, gives a precise measure of the amount of ion
condensation in the planar double layer. Results are presented
for 0.001, 0.01, and 0.1M monovalent and divalent restricted
primitive model electrolytes using the singlet hypernetted chain
closure with the first bridge diagram. In general the apparent
surface charge is less than the actual surface charge, due to the
influence of ion­ion correlations. Thus the Poisson­Boltzmann
approximation underestimates the actual surface charge and
overestimates the amount of counterion binding. At high sur­
face charge densities the apparent surface charge saturates, and

Source: Attard, Phil - School of Chemistry, University of Sydney

Collections: Chemistry