Macromolecules, Vol.32, No.10, 3469-3473, 1999
Short range order of rodlike polyelectrolytes in the isotropic phase
The local order of aqueous solutions of rodlike polyelectrolytes is analyzed. It is shown that the scaling of the full width at half-height of the first peak of the static structure factor with the concentration C of polyelectrolyte is similar to the scaling of the peak position of the first maximum: it changes from C-1/3 to C-1/2 as C varies from the dilute to the semidilute regime. This result enables us to estimate the number of ordered next neighbor shells, N, arranged locally around a central particle. It is shown, in goad agreement with Monte Carlo results, that N similar to 1 when the ionic strength of the solution, I, is similar to 10(-7)-10(-5) M and the polyelectrolyte surface charge in the solution, Q, is on the order of hundreds of electrons. This order decreases when I goes to similar to 10(-3)-10(-2) M and Q decreases by 1 order of magnitude.