Eur. Phys. J. E 5, 97-103
The osmotic coefficient of rod-like polyelectrolytes: Computer simulation, analytical theory, and experimentM. Deserno1, C. Holm1, J. Blaul2, M. Ballauff2 and M. Rehahn3
1 Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
2 Polymer-Institut, Universität Karlsruhe, Kaiserstraße 12, 76128 Karlsruhe, Germany
3 Institut für Makromolekulare Chemie, Technische Universität Darmstadt, Petersenstraße 22, 64287 Darmstadt, Germany
(Received 25 July 2000 and Received in final form 4 December 2000)
The osmotic coefficient of solutions of rod-like polyelectrolytes is considered by comparing current theoretical treatments and simulations to recent experimental data. The discussion is restricted to the case of monovalent counterions and dilute, salt-free solutions. The classical Poisson-Boltzmann solution of the cell model correctly predicts a strong decrease in the osmotic coefficient, but upon closer look systematically overestimates its value. The contribution of ion-ion-correlations are quantitatively studied by MD simulations and the recently proposed DHHC theory. However, our comparison with experimental data obtained on synthetic, stiff-chain polyelectrolytes shows that correlation effects can only partly explain the discrepancy. A quantitative understanding thus requires theoretical efforts beyond the restricted primitive model of electrolytes.
61.41.+e - Polymers, elastomers, and plastics.
87.15.Aa - Theory and modeling; computer simulation.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001