Dilute Solution Properties of Anionic Poly(potassium-2-sulphopropylacrylate)

The dilute solution properties of an anionic polyelectrolyte, poly(potassium-2-sulphopropylacrylate) (poly(SPA)) are studied by measurements of intrinsic viscosity, degree of binding, ionic strength and critical micelle concentration. The intrinsic viscosity of this polyelectrolyte is related to the type and concentration of the salt added. The intrinsic viscosity behaviour of an anionic polyelectrolyte resulting from the electrostatic repulsive force of the polymer chain is in contrast to that of a polyampholyte. The polyelectrolyte in high concentration of NaCl has a low degree of binding, indicating that the proton ion (H + ) is relatively difficult to bind to the sulphonate group (SO 3 - ) at the polymer end. An increase in ionic strength causes the pK a to decrease at the half-neutralization point. The monomer solutions exhibit a plot typical of those observed for detergents, with a break in the curve occurring at the critical micelle concentration. For the polymer solutions, no break in the equivalent conductance curve was found for the concentrations studied.