In the absence of added salts

the viscometric behavior of Na-salts of sulfonated polysulfone in DMF has been experimentally studied. A new empirical equation expressing the relationship between reduced Ariscosity and concentration of polyelectrolyte solutions is proposed as followingWhen this equation was applied to our experimental data and to that of Fuoss'

the results obtained were satisfactory. With the electroviscous effect and extension effect of polyion

this empirical equation has been discussed.