Model solutions for studies of salt-free polyelectrolytes

The structure and dynamics of poly(N-methyl-2-vinylpyridinium chloride) (PMVP) was studied in three nonaqueous solvents using dynamic light scattering. It was found that by eliminating the influences of poor backbone solvation, multiple relaxation modes persist in the dynamic light scattering. Using multiple solvents to vary the dielectric constant by a factor 5, qualitative effect and little quantitative effect on the extraordinary regime scattering were absent. DLS from solutions of the neutral chain and salt-free solutions of the polyelectrolyte displayed dramatic differences whereas the scattering from a high-salt solution of the polyelectrolyte paralleled the scattering from the neutral chain. In general, these results demonstrate the flexibility and merits of the PMVP system.