ELECTRIC TRANSPORT OF POLYELECTROLYTES IN AQUEOUS SALT-FREE SOLUTIONS

The counterion condensation theory of Manning has influenced polyelectrolyte research since its inception. Principally,the charge density parameter,xi, governs the solution properties of polyelectrolyte solutions. The theory proposes that counterion condensation occurs when xi=1 for monovalent counterions. It was desirable to investigate the critical point for the poly(acrylates), namely aqueous solutions of sodium poly(acrylic) acid and sodium poly(methacrylic) acid at several charge densities. The conductance, electric mobility of the polyion and the counterion, sodium, were measured along with the reduced viscosities of these solutions to elucidate any configurational changes as xi(c)=1 is approached. The degree of dissociation of the polyions were calculated and compared to the theory.