Influence of solvent quality and dielectric permittivity on the solution properties of poly(ionic liquids)

This proposal outlines a study on the influence of solvent quality and dielectric permittivity on the solution properties of poly(ionic liquids). Earlier experiments have shown that in high dielectric constant solvents, poly(ionic liquids) behave similarly to classical polyelectrolytes, and in solvents of low dielectric constant, they behave like neutral polymers. The proposed study aims 1) to establish the scaling of the correlation length and zero-angle scattering intensity with polymer concentration for solutions in THF, were neutral polymer-like behaviour has been observed, and 2) to investigate the combined influence of solvent quality and dielectric permittivity by using two solvents of similar dielectric constant but different solvent quality. The experiments will involve measuring the correlation length and mass per unit length of the chains from SANS measurements combined with viscosity and electrical conductivity measurements. The investigation will yield structural and thermodynamic information on poly(ionic liquids) and resolve the influence of counterion solvation on the dissociation of counterions from the backbone and the resulting changes in chain conformation.