Conformation des polyacrylamides partiellement hydrolyses en solution aqueuse

A series of hydrolyzed commercial polyacrylamide samples were fractionated by successive precipitation fractionation. The radius of gyrationRGand the intrinsic viscosity [η] of the fractions were measured as a function of the molecular weight and the NaCl concentrationcs. The fractions were found to present the classical behaviour of polyelectrolytes with a conformation of expanded coils atcs= 0,1 mol/l. By increasing the salt concentration, the dimensions of the coils were found to become those of the unhydrolyzed, less expanded, polyacrylamide molecules.