Hydrophobically modified water-soluble polymers have been prepared by copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and isodecyl methacrylate (iDMA) in N,N-dimethylformamide under nitrogen atmosphere, varying the composition feed. Fluorescence spectroscopy was used to further confirm the copolymers self-aggregate in water. Critical concentration of the self-aggregate formation (CAC) decreased by increasing the molar fraction of iDMA in the AMPSco copolymers and varied between 1.20 and 0.04 g/L depending on the degree of hydrophobic modification. Hence, copolymer composition and charge density allowed tuning the pseudomicellar characteristics of these new amphiphilic copolymers. The addition of a salt or a low-molecular-weight surfactant was studied. Binding of CTAB to the AMPS(co) copolymers leads to a high decrease of CAC, i.e., 0.006 g/L. Effect of the composition in the viscosimetric behavior of the hydrophobically modified copolymers AMPS(co) was investigated. The removal of single metal ions, Cu2+, and m-cresol from aqueous solutions by ultrafiltration with the help of the copolymers was investigated. Equilibrium dialysis experiments demonstrate that the formation of hydrophobic microdomains can be used to control the sequestration of foulants, and thus these novel copolymers have potential application as polymeric surfactants in micellar-enhanced ultrafiltration processes for water purification. (c) 2007 Wiley Periodicals, Inc.