CONFORMATIONS OF STAR-BRANCHED POLYELECTROLYTES

Scaling theory describing the conformations of weakly charged star-bra nched polyelectrolytes in dilute and semi-dilute salt-free solutions i s developed. The dependence of the star size on the number of branches as well as on the solution concentration is analyzed. It is shown tha t the star size increases with an increase in the number of branches, f, at small f and tends to a constant value at large f. An increase in the concentration of stars in a solution results in a decrease in the star size R according to the power law: R similar to c(-1/3) in the r ange of a moderate concentration and R similar to c(-1/4) at larger co ncentration. For stars with a small number of branches the behavior R similar to c(-1/2) in a certain concentration range is also predicted. The collapse transition which occurs in the polyelectrolyte star if t he solvent strength decreases is considered; it is shown that the coll apse of a polyelectrolyte star may be accompanied by the loss of the s tar spherical symmetry.