Computer simulations of a polyelectrolyte chain with a mixture of multivalentsalts

Abstract

Diluted solutions of a single, electrically charged polymer chain, its monovalent counterionsand two kinds of multivalent salts are investigated. In particular, the influence of the saltconcentrations and valences on the mean effective charge per monomer, total inner energy,radius of gyration and various pair correlation functions of the monomers and free ions areanalysed. The calculations show that it is the four-valent and three-valent ions, oppositelycharged to the monomers, that mostly occupy the space around the polymer andtremendously increase their number there compared to that in the bulk. Furthermore,reductions in the polymer size and effective charge per monomer appear, especially forincreasing amount of the four-valent salt. Thus, there is an evidence for polymerconformational changes associated with the ion condensation onto the chain.