Eur. Phys. J. E 1, 115-125
Charge distribution on annealed polyelectrolytes
M. Castelnovo - P. Sens - J.-F. Joanny
Institut Charles Sadron, 6 rue Boussingault, 67083
Strasbourg Cedex, France
castel@ics.u-strasbg.fr
Received 19 March 1999 and Received in final form 2 August 1999
Abstract
We investigate the equilibrium charge distribution along a single annealed
polyelectrolyte chain under different conditions. The coupling between the conformation
of the chain and the local charge distribution is described for various solvent
qualities and salt concentration. In salt free solution, we find a slight charge
depletion in the central part of the chain: the charges accumulate at the ends. The
effect is less important if salt is added to the solution since the charge
inhomogeneity is localized close to the chain ends over a distance of order of the
Debye length. In the case of poor solvent conditions we find a different charge per
monomer in the beads and in the strings in the framework of the necklace model. This
inhomogeneity leads to a charge instability and a first order transition between
spherical globules and elongated chains.
PACS
61.25.Hq Macromolecular and polymer solutions; polymer melts; swelling -
36.20.Ey Conformation (statistics and dynamics) -
05.90.+m Other topics in statistical physics, thermodynamics, and nonlinear
dynamical systems
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
