The cationic monomers, MPDMAC(16) and MPDMAC(18) were obtained by quaternization of methacrylamidopropyl-N,N'-dimethylamine with n-alkyl iodides (1-iodohexadecane and 1-iodooctadecane) in ethyl acetate. Hydrophobic ionomers of MPDMAC16 and MPDMAC(18) with N-substituted acrylamides were prepared at 60 +/- 0.1 degrees C in DMF using AIBN initiator. The cationic monomers and ionomers were characterized by H-1- and C-13-NMR spectroscopy. The copolymer composition was evaluated from elemental analysis data using carbon/nitrogen (C/N) ratio. The molecular weight distributions of ionomers were obtained from GPC analysis. Both the dilute solution and concentrated solution properties of ionomers were studied by viscometry at 30 degrees C. (c) 2005 Wiley Periodicals, Inc.