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# Flexible Polyelectrolytes with Monovalent Salt

Physica A: Statistical Mechanics and its Applications (Impact Factor: 1.73). 07/2004; 357(1). DOI: 10.1016/j.physa.2005.05.048

Source: arXiv

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Marcia Barbosa, Mar 21, 2015 Available from: Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

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**ABSTRACT:**We evaluate an approximate free energy for polyelectrolyte gels, including entropic effects due to flexibility of chains and electrostatic effects due to net charge of chains. The electrostatic terms depend on the binding fraction of ions m to the network and on the degree of swelling α of the chains. One term describes the interaction of the chains with the ionic solution and the other comes from the internal partition function of the macromolecules of the gel. The equilibrium values of m, α and the mixing parameter χ are obtained. This is also done for some experimental values of gel strength and volume fractions. The critical point for volume phase transitions is evaluated, and we find that the critical temperature increases as the charge on the chains increases, while the critical volume fraction of polymer decreases.Colloids and Surfaces A Physicochemical and Engineering Aspects 06/2006; 281(1):184-189. DOI:10.1016/j.colsurfa.2006.02.037 · 2.75 Impact Factor -
##### Article: Polyampholyte solutions in the presence of salt ions having different valences: Computer simulation

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**ABSTRACT:**The properties of dilute solutions of regular polyampholytes in the presence of a low-molecularmass salt were studied by means of stochastic dynamics simulation. The number-average concentration of polymer units in solution did not exceed 0.038, a value that is below the coil overlap concentration at N= 1024. The effect of charge (valence) of ions of an added salt on the macromolecule size and distribution of the salt inside the polymer coil at different temperatures was considered. It was found that the condensation of salt ions over the temperature range examined (1 ≤T≤2ε/k B) takes place in the case of multiply charged systems of the (+4−4) or (+4−2) type. The maximal penetration of salt ions into the volume of the macromolecule was observed in the case of a (+2−2) salt.Polymer Science Series A 02/2008; 50(2):206-211. DOI:10.1134/S0965545X08020168 · 0.92 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Counterion adsorption on a flexible polyelectrolyte chain in a spherical cavity is considered by taking a “permuted ” charge distribution on the chain so that the “adsorbed” counterions are allowed to move along the backbone. We compute the degree of ionization by using self-consistent field theory (SCFT) and compare with the previously developed variational theory. Analysis of various contributions to the free energy in both theories reveals that the equilibrium degree of ionization is attained mainly as an interplay of the adsorption energy of counterions on the backbone, the translational entropy of the small ions, and their correlated density fluctuations. Degree of ionization computed from SCFT is significantly lower than that from the variational formalism. The difference is entirely due to the density fluctuations of the small ions in the system, which are accounted for in the variational procedure. When these fluctuations are deliberately suppressed in the truncated variational procedure, there emerges a remarkable quantitative agreement in the various contributing factors to the equilibrium degree of ionization, in spite of the fundamental differences in the approximations and computational procedures used in these two schemes. Furthermore, it is found that the total free energies from the truncated variational procedure and the SCFT are in quantitative agreement at low monomer densities and differ from each other at higher monomer densities. The disagreement at higher monomer densities is due to the inability of the variational calculation to accurately compute the solvent entropy at higher concentrations. A comparison of electrostatic energies (which are relatively small) reveals that the Debye-Hückel To whom any correspondence should be addressedMacromolecules 02/2009; 42(4):1370-1379. DOI:10.1021/ma801799e · 5.80 Impact Factor