Prev. Article Next Article Table of Contents

Article

The Influence of Ionic Dispersion Potentials on Counterion Condensation on Polyelectrolytes

Mathias Boström,* David R. M. Williams, and Barry W. Ninham^†

Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200

J. Phys. Chem. B, 2002, 106 (32), pp 7908–7912

DOI: 10.1021/jp0256084

Publication Date (Web): July 19, 2002

Corresponding author. E-mail: mtb110@rsphysse.anu.edu.au.

†

Present address: Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Italy.

Abstract

The prevalent theories for polyelectrolytes have not been able to describe the experimentally observed ion specificity found at high ion concentrations for counterion condensation and conformational transitions. One important source of ion specificity missed in these theories is the dispersion force that acts between an ion and the cylindrical polyion surface. Here, we solve the cylindrical Poisson−Boltzmann equation numerically in the presence of ionic dispersion potentials. We demonstrate that ionic dispersion forces have important influences on ionic distributions and potentials. This influence increases with increasing concentration reflecting that specific ion effects are observed only at high concentrations.

View: Full Text HTML | Hi-Res PDF