1H NMR Investigations of the Interactions between Anionic Surfactants and Hydrophobically Modified Poly(acrylamide)s

Article abstract of DOI:10.1021/j100098a039

The binding of alkylbenzenesulfonates to various hydrophobically modified poly(acrylamide)s which differ in the degree of hydrophobe modification has been studied by 1H NMR.The extent of surfactant binding to copolymer, as evidenced by the change in chemical shift and line broadening, was found to be dependent on the degree of hydrophobic substitution.No evidence for surfactant binding was found in the unmodified poly(acrylamide).The exchange of the free surfactant between two sites, one corresponding to the free surfactant and the other corresponding to surfactant bound to copolymer, was found to be fast on the 1H NMR chemical shift time scale.The changes in line shape of certain peaks in the 1H NMR spectrum of the surfactant were attributed to restricted rotation of the aromatic ring of the surfactant as a result of binding to the copolymer.