On the interaction of single-charged counterions with a macroion in arbitrary media

✍ Scribed by Mikhail L. Brenerman; Ibrahim R. Manyurov; Rashid G. Tukhvatullin; William P. Barabanov

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 310 KB
• Volume: 35
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19970115)35:1<33::aid-polb2>3.0.co;2-w

✦ Synopsis

This article represents an attempt to develop a generalized approach to the creation of a model of ionic interactions in polyelectrolyte solutions. Particular attention is given to the problems of considering nonelectrostatic interactions. A theoretical description is made of solvophobic effects arising in nonaqueous media between undissociated salt units. The influence of such phenomena on the counterion association is illustrated with experimental data. The model is based on the consideration of the configurational integral of a macromolecule. The solvent is assumed to have different solvation properties with respect to different groups within the polymer, resulting in an attractive component in the interaction potential between the undissociated units. It is shown that with a certain critical fraction of undissociated units the ''phase separation'' of a macromolecule into coil and globular parts may occur. This is accompanied by drastic enhancement of counterion association and suppression of the growth of the electrostatic potential of a macroion. With a further increase in the number of such units the complete globulization of a macromolecule takes place. The theoretical pH and conductivity dependences on the neutralization degree are calculated and correlated with experimental results.