Effect of [Zr(α-PW11O39)2]10− Polyoxometalate on the Self-Assembly of Surfactant Molecules in Water Studied by Fluorescence and DOSY NMR Spectroscopy

Abstract

The catalytic fragmentation of hydrophobic proteins by polyoxometalates (POMs) requires the presence of surfactants in order to increase the solubility of the protein. Depending on the nature of the surfactant, different effects on the kinetics of protein hydrolysis are observed. As the molecular interactions between the POMs and surfactants in solutions have been scarcely explored, in this study, the interaction between the catalytically active Keggin polyoxometalate [Zr(α-PW11O39)2]10− and four different surfactants—sodium dodecyl sulfate (SDS), dodecyldimethyl(3-sulfopropyl)ammonium (Zw3-12), dodecyldimethyl(3-sulfopropyl) ammonium (CHAPS), and polyethylene glycol tert-octylphenyl ether (TX-100)—have been studied in aqueous media. The effect of polyoxometalate on the self-assembly of surfactant molecules into micelles and on the critical micellar concentration (CMC) has been examined by fluorescence spectroscopy and diffusion ordered NMR spectroscopy (DOSY).

Keywords

• polyoxometalates
• zirconium
• micelles
• DOSY
• surfactant
• fluorescence
• critical micellar concentration
• micelle size