Potential energy in the electrical double layer and slipping plane potential

Previously, the authors have analysed a model of the electrical double layer, demonstrating the positiveness of the ζ potential arising when aluminium particles are introduced into distilled water. Further, they demonstrated that an increase in conductivity led to the appearance of a negative ζ potential. The same type of phenomenon can be found when electrostatic potential energies are analysed by applying the Poisson-Boltzmann equation. The present paper provides a comparison of these two double layer models obtained from experimental measurements and from calculation respectively. From the comparison, a value of 5.3×10^-11 m²/s is deduced for the coefficient of molecular diffusion. This is close to the value of 7.35×10^-11 m²/s given by the Chemical Handbook for polyethylene oxide