The point ion modified PoissonBoltzmann theory for a planar electric double layer with different permittivities for the electrode, inner layer and diffuse layer
Abstract
The planar electric double layer is modelled by an electrode, inner layer and diffuse layer whose constant permittivities differ. A point ion modified PoissonBoltzmann analysis is made of the model with the ions in the diffuse layer having a distance of closest approach to the electrode, which is greater than the inner layer thickness and mimics the ion radius of a primitive model electrolyte. Comparisons are made with existing Monte Carlo simulations for uncharged and charged electrodes. For 1:1 and 2:1 electrolytes with a charged electrode, the modified PoissonBoltzmann theory successfully predicts the singlet ion normalised density functions and the mean electrostatic potential. With the uncharged electrode, the neglect of ion size is more critical and the theoretical predictions are now poor at the higher concentrations.
 Publication:

Molecular Physics
 Pub Date:
 November 2014
 DOI:
 10.1080/00268976.2014.922706
 Bibcode:
 2014MolPh.112.2963O
 Keywords:

 planar electric double layer;
 imaging;
 point ion electrolyte;
 modified PoissonBoltzmann theory