Ii. Potemkin et al., Associating polyelectrolytes: Finite size cluster stabilization versus physical gel formation, J CHEM PHYS, 111(6), 1999, pp. 2809-2817
The theory of phase equilibria in the solutions of associating polyelectrol
yte telechelic chains proposed earlier is generalized to take into account
the possibility of existence in the solutions of finite size thermodynamica
lly stable clusters in addition to the formation of macroscopic physical ge
l. It is shown that in some region of polymer concentrations and energies o
f attraction between the end groups of the chain (stickers) the size distri
bution of chain clusters has a maximum, i.e., the solution is dominated by
the clusters of optimum size. The stabilization of such a cluster is due to
the interplay between the energy of attraction of stickers, on the one han
d, and the Coulomb interaction together with the contribution from the tran
slational entropy of counter ions, on the other hand. For small enough opti
mum clusters direct Coulomb interactions are more important, while for larg
e optimum clusters the main reason for stabilization is connected with the
translational entropy. This type of stabilization mechanism should be quite
general for any polyelectrolyte system with attraction. (C) 1999 American
Institute of Physics. [S0021-9606(99)50329-2].