title: Effective charge of polyelectrolytes as a function of the dielectric constant of a solution.
abstract: The combination of diffusion and electrophoresis NMR is applied to determine the effective charge of poly(styrene sulfonate) in solution. While electrophoresis NMR yields the electrophoretic mobility of the molecules in solution, the hydrodynamic friction is determined from diffusion NMR. From the force balance between electrostatic force and hydrodynamic friction, the effective charge of the molecule is determined free of any model. In the present study poly(styrene sulfonate) has been investigated in mixtures of water and methanol of varying composition. The lower dielectric constant in the mixtures with high methanol content results in a drastically reduced effective charge of the polyelectrolytes. The reduced effective charge along the polymer chain is the reason for a much more compact conformation of the polyelectrolyte, which is seen in a smaller hydrodynamic size of the molecule.
authors.affiliation: Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Böhme
authors.forename: Ulrich
authors.initials: U
authors.lastname: Scheler
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004058:Diffusion; D004553:Electric Conductivity; D004573:Electrolytes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D000432:Methanol / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D004573:Electrolytes; D011137:Polystyrenes; D014867:Water; C003321:polystyrene sulfonic acid; D000432:Methanol