Preparation and Solution Properties of Amphiphilic Sulfonated Acrylamide Copolymers

Copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and N-tert-butylacrylamide has been carried out in methanol at 60°C using AIBN as initiator. Both IR and 1H NMR spectroscopy indicated that monomer conversions exceeding 95% were reached in the copolymerizations. Copolymers containing more or equal to ≈ 15 mol-% AMPS were soluble in water and had an amphiphilic character. Analysis by dilute solution viscometry, quasi-elastic light scattering, and size exclusion chromatography in water and aqueous KCl solution showed that the AMPS homopolymer and the copolymers behave as polyelectrolytes. Light scattering analysis and atomic force microscopy indicated the presence of aggregates in aqueous solutions of a copolymer containing 15 mol-% AMPS. Gravimetrical measurements showed that the water absorption of the copolymers in humidified air increases almost linearly with the AMPS content of the copolymers.