1202.4282 (T. Sajevic et al.)

Correlation between flexibility of chain-like polyelectrolyte and
thermodynamic properties of its solution    [PDF]

T. Sajevic, J. Rescic, V. Vlachy

Structural and thermodynamic properties of the model solution containing
charged oligomers and the equivalent number of counterions were studied by
means of the canonical Monte Carlo simulation technique. The oligomers are
represented as (flexible) freely jointed chains or as a linear (rigid) array of
charged hard spheres. In accordance with the primitive model of electrolyte
solutions, the counterions are modeled as charged hard spheres and the solvent
as dielectric continuum. Significant differences in the pair distribution
functions, obtained for the rigid (rod-like) and flexible model are found but
the differences in thermodynamic properties, such as, enthalpy of dilution and
excess chemical potential, are less significant. The results are discussed in
light of the experimental data an aqueous polyelectrolyte solutions. The
simulations suggest that deviations from the fully extended (rod-like)
conformation yield slightly stronger binding of counterions. On the other hand,
the flexibility of polyions, even when coupled with the ion-size effects,
cannot be blamed for qualitative differences between the theoretical results
and experimental data for enthalpy of dilution.

View original: http://arxiv.org/abs/1202.4282