Influence of Backbone Solvation on Small Angle Neutron Scattering from Polyelectrolyte Solutions

Abstract

Recent theoretical and experimental studies of polyelectrolyte solutions have suggested that hydrophobic interactions between the chain backbone and the solvent lead to some of the essential observations of polyelectrolyte solution scattering. In the current paper we present small angle neutron scattering data on a polyelectrolyte, poly( N -methyl-2-vinylpyridinium chloride) dissolved in ethylene glycol where the hydrophobic effect is not present. This system shows the same general pattern, a peak at finite wavevector and steep upturn at low wavevector, as for those having hydrophobic interactions so that the influences of poor backbone solvation appear to be unessential for explaining the characteristics of polyelectrolyte scattering data. We demonstrate that in the scattering from polyelectrolytes after the addition of salt, the unusual peak and steep upturn are suppressed and the scattering parallels scattering from the neutral chains.