The electrolytic cond. and soln. viscosity of some strong polycations, which possess the ammonium quaternary centers either attached to an acrylic macromol. chain (polycation PDMAEMQ type), or in the backbone (polycation PCA type), have been measured to identify how charge d., polyelectrolyte concn., solvent polarity as well as counterion nature influence the ultimate soln. properties. The investigations reveal for all polycations an increase of the equiv. cond. with decreasing concn. The onset of the strong increase shifts to lower concn. if the charge d. augments. Polyelectrolyte behavior was obsd. for PCA5D1 in the mixt. of water/methanol for all solvent compns. employed and in the mixt. of water/acetone up to 60 vol. % of acetone content. At all exptl. concns. the reduced viscosity decreases with the dielec. const. of the mixed solvent. Furthermore, the specific interaction between several mono- and divalent counterions with some of these polycations was clearly proved by conductometric measurements. [on SciFinder (R)]