¹³G NMR and ESR studies on the association between sodium 3-dodecy I ether-2-hydroxypropy1-1-sulfonate and polyvinylpyrrolidone

Abstract

The surfactant, sodium 3-dodecy] ether-2-hydroxypropyl-l-sulfonate(SDEHS) was synthesized. The association and standard free energy of formation of the complex between sodium 3-dodecyl etheT-2-hydroxypropyl-l-sulfonate(SDEHS) and polyvinyl-pyrrolidone(PVP) in an aqueous solution have been investigated using C NMR, ESR spectra, and surface tension measurements at the air/ water interface. ¹³C NMR and ESR spectra all indicate that the basic structure of the complex is a micelle-like aggregate, the SDEHS molecules assembling on the methylidync(a) the methylene(α ) carbon in the backbone, and the methyleneβ carbon attached to the nitrogen of PVP molecules, and shield hydrocarbon groups on the surface of the micelle from contacting with water. The measurement results ofsurface tensions show that the amount of surfactant bound to the polymer are linear function of the polymer concentrations ( φ,WI% )i. e( c₂ -c₁ and the miceltization in the presence of PVP occurs at a lower concentration than the critical micelle concentration of SDEHS. The effectiveness of PVP in lowering the free energy of formation of the surfactant aggregates in aqueous solutions increases with the concentrations of PVP.

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Notes on contributors

JINGCHENG MAO

To whom correspondence should be addressed.

JIYE HU

The present address is Department of Base, laiyang Agricultural College, Laiyang, 265200