Eur. Phys. J. B 4, 205-217 (1998)
https://doi.org/10.1007/s100510050371

Effects of ionic strength and charge annealing in star-branched polyelectrolytes

¹ University of Wageningen, Department of Physical and Colloid Chemistry, 6703 HB Wageningen, The Netherlands
² University of Pittsburgh, Department of Chemical Engineering, Pittsburgh PA 15261, USA

Corresponding author: ^a borisov@fenk.wau.nl

Received: 10 November 1997
Revised: 16 February 1998
Accepted: 1 April 1998
Published online: 15 July 1998

Abstract

We have developed a scaling theory that describes the conformations of weak star-branched polyelectrolytes in dilute solutions. The dependences of the overall star size on the number of branches and on the ionic strength of the solution (tuned by the addition of low molecular weight salt) are analyzed. The intrinsic structure of the polyelectrolyte stars in salt-free and salt-added solutions is discussed in terms of concentration and elastic blobs. In contrast to neutral stars, the swollen corona of the polyelectrolyte star consists of blobs which are not closely packed. We have shown that the size of star polyelectrolytes is less sensitive to the variation in the ionic strength than the size of linear polyelectrolytes. The effects of the ionization-recombination balance in the star polyelectrolyte were taken into account. For polyelectrolytes with small ionization constant, the size of the star depends nonmonotonically on the number of branches and on the ionic strength of the solution due to recombination of counterions with charged monomers.