A novel hydrophobically associating polyacrylamide (PAAHO) of acrylamide, 2-acrylamide-2-methylpropane sulfonate, capsaicin-like monomer N-(4-hydroxy-3-methoxy-benzyl) acrylamide (HMBA), and hydrophobic monomer octadecyl acrylate was synthesized by micellar copolymerization and characterized by fourier transform infrared spectrum, ultraviolet-visible spectrum, and thermogravimetric analysis, respectively. By adjusting various factors, a series of PAAHOs with different block structures were prepared. The hydrophobic association properties were then studied by viscometry and fluorescence spectrometry. Solution behavior was examined with respect to polymer concentration, ionic strength, and temperature. Also, the antibacterial activity was investigated. Results show that initiator amount influenced not only the molecular weight but also the yield and composition of resulting copolymers. PAAHOs possess strong thickening capability, and the hydrophobic association is enhanced as hydrophobe content increases. PAAHOs have excellent viscosity retention in brine solution and exhibit unique rheological behavior including a salt-thickening response. Incorporation of HMBA greatly improves the thermal stability of PAAHO. Moreover, PAAHO is endowed with considerable antibacterial activity against Escherichia coli and Staphylococcus aureus.

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