Eur. Phys. J. E (2014) 37: 75
https://doi.org/10.1140/epje/i2014-14075-4

Regular Article

Adsorption of pH-responsive polyelectrolyte chains onto spherical macroions

Instituto de Biociências, Letras e Ciências Exatas, UNESP - Univ Estadual Paulista; Departamento de Física, Rua Cristovão Colombo 2265, Jd. Nazareth, 15054-000, São José do Rio Preto, São Paulo, Brazil

^* e-mail: sidneyjc@ibilce.unesp.br

Received: 31 March 2014
Revised: 22 July 2014
Accepted: 5 August 2014
Published online: 27 August 2014

Abstract

The adsorption of pH-responsive polyelectrolyte chains onto oppositely charged spherical macroions is investigated through Metropolis Monte Carlo simulations and the Weighted Histogram Analysis Method. In this case, the polymer charge density is susceptible to the solution conditions, such as salt concentration and pH, as well as the presence of other charged species. Thus, the pH and ionic strength variations leads to abrupt variations of the conformational and electric properties of the chain, as a result of first-order-like transition between the adsorbed and desorbed states. The diagram of states as a function of ionic strenght and p H is provided. Despite the inhomogeneities in the polyelectrolyte charge distribution induced by the macroion presence and its dependence on ionic strength, the scaling relation between the macromolecular charge densities and the critical Debye length is obtained in agreement with experimental investigations.