This article describes the first of a new series of preparations of water-soluble acrylamide, substituted acrylamide copolymers and related homopolymers. Objectives of this work were to measure the progressive influence on the hydrodynamic volume and other properties contributed by incorporation of N,N-dimethylacrylamide (DMA) into a series of high molecular weight acrylamide copolymers. Traditional photoacoustic Fourier transform infrared, C-13 NMR, and elemental analysis were used for primary characterization. A series of tests using viscometric, gel permeation, chromatographic, and multiangle laser light scattering methods were then used to measure the hydrodynamic volumes of the products. Copolymers incorporating 14, 23, 43, and 63 mol percent DMA with molecular weights of greater than 5 X 10(6) g/mol were, obtained with yields of better than 70%. Aqueous solutions of these polymers showed little or no decrease in radii of gyration or intrinsic viscosity when low concentrations of sodium chloride were added, in contrast to its effect on solutions of polyacrylamide itself. For the copolymers, higher values were obtained for < r(g) > and [eta], than were observed for acrylamide homopolymers of comparable molecular weight.