The transport properties of polyelectrolytes with N-alkyl-N,N-dimethyl-N-(2-hydroxypropyl)ammonium chloride pendent groups (alkyl = octyl, dodecyl, or cetyl) randomly distributed along a polysaccharide backbone (dextran) in solutions were studied with viscometry and conductometry. This investigation mainly considered the influence of the side-chain length and the solvent polarity on the polyelectrolyte behavior in salt-free aqueous solutions. The viscometric data indicated that all the copolymers exhibited polyelectrolyte behavior, and they were plotted in terms of the Rao equation. The viscosity of the polycation with dodecyl as alkyl substituent was also measured in solvent mixtures of water and methanol. The conductometric behavior of these cationic polysaccharides was found to be influenced by the alkyl side-chain length and the solvent polarity. A nonlinear dependence of the equivalent conductivity on the dielectric constant of the solvent was observed. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 3031-3038,2009