Water pollution is one of the most serious environmental problems facing society. The objective of this study was to provide an efficient and inexpensive way of removing Cr(III) from polluted water. Novel twin-tailed hydrophobically associating copolymers (PAAD) were prepared by micellar copolymerization of acrylamide (AM) and sodium 2-acrylamido-2-methylpropane sulfonate with N,N-dibutylmethacrylamide in an aqueous solution. The PAAD series, comprising copolymers of different molecular weights (ranged from 1.42 to 1.78 × 106 g/mol) and compositions was characterized by gel permeation chromatography–multiangle laser light scattering, 1H NMR and FTIR spectroscopy, and elemental analysis. The surface activity, morphology, and aggregation properties of PAAD samples were measured by surface tension and dynamic light scattering. A schematic representation of the formation of Cr(OH)3 and its precipitation using PAAD samples as coagulant aid is discussed in the article. In addition, the Cr(OH)3–copolymer interaction, as investigated by precipitation experiments, demonstrated that these copolymers have good Cr(OH)3 binding capacity and potential as coagulant aid for the removal of Cr(III) from polluted water. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41028.