AbstractThe intrinsic viscosities of low molecular weight fractions of atactic poly(acrylic acid) at 50% and 100% neutralization and at several concentrations of added sodium chloride is studied. In salt‐free solutions the 100% neutralized polymer assumes the rigid rod form. The results at concentrations of sodium chloride higher than 0,02 mol/l can be interpreted in terms of a non‐draining random coil polymer.The values of KΘ are determined using the Stockmayer‐Fixman method; there is an increase in KΘ on going from poly(acrylic acid) in dioxane through the 50% neutralized form in 0,5M sodium chloride solution to the 100% neutralized form in 1,5M sodium chloride solution, indicating the continued effect of short‐range electrical forces at the Θ‐point.