Effect of Hydrophobe Content on Intra- and Interpolymer Self-Associations of Hydrophobically Modified Poly(sodium 2-(acrylamido)-2-methylpropanesulfonate) in Water

Abstract

As an extension of our previous fluorescence studies of random terpolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS), N-dodecylmethacrylamide (DodMAm), and 1 mol % N-(1-naphthylmethyl)methacrylamide (fluorescence label), intra- and interpolymer self-associations of these polymers in aqueous solution were investigated by 1H NMR relaxation, fluorescence depolarization, and quasielastic light scattering (QELS) methods. These studies were conducted with a focus on the effect of the DodMAm content (fDod) on the association behavior of these polymers over the fDod range of 10−60 mol %. At fDod = 10 mol %, the polymer-bound dodecyl groups undergo mostly intrapolymer association, but a small fraction of the hydrophobes undergo interpolymer association, QELS showing a bimodal distribution as the polymer concentration is increased. In the range 10 < fDod ≤ 50 mol %, however, QELS data indicated a strong preference for intrapolymer associations independent of the polymer concentration, leading to the ...