Research article

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Cationic, hydrophobically associating polyacrylamide (PDA) was synthesized via the inverse miniemulsion polymerization in the presence of template. Dimethyloctane(2- acrylamidopropyl)ammoniumbromide (DOAB) was synthesized via quaternization reaction and used as the hydrophobic monomer. Polyacrylic acid (PAA) was used as template for the oppositely charged DOAB. The distribution of DOAB in the inverse miniemulsion and the solution viscosity behaviors of PDA were investigated. The results showed that the complexes of DOAB and PAA were located not only at the interface of the inverse miniemulsion droplets and oil phase but also in the interior of inverse miniemulsion droplets. PDA prepared with template exhibited remarkable enhancement of solution viscosity (thickening ability). And the optimal thickening ability was obtained when the aqueous phase pH was 6.5 and the ratio of DOAB to PAA was 1. The thickening ability of PDA was improved with increasing DOAB content. PDA prepared with template showed stronger association ability than that prepared without template for its longer hydrophobic block structure, which was further supported by the plots of fluorescence spectra.