Study of the coadsorption of an anionic surfactant and an uncharged polymer at the aqueous solution/hydrophobic surface interface by sum frequency vibrational spectroscopy

COLL 231

Michael T.L. Casford1, Paul B. Davies1, and David J. Neivandt2. (1) Dept. of Chemistry, Cambridge University, Lensfield Rd., Cambridge, United Kingdom, (2) Dept. of Chemical and Biological Engineering, University of Maine, 117 Jenness Hall, Orono, ME 04469-5737
The co-adsorption of an anionic surfactant, sodium dodecyl sulfate (SDS), and a non-ionic polymer poly(ethylene oxide) (PEO), has been studied at the hydrophobic solid/solution interface via the non-linear optical technique of Sum Frequency vibrational Spectroscopy (SFS). The polar orientation and degree of conformational order of the surfactant has been determined as a function of SDS concentration in the presence of a fixed concentration of various molecular weight PEO polymers. The adsorbed amounts of the polymer and surfactant have been quantified through Infrared Attenuated Total internal Reflection (IR-ATR). Surface tensiometery measurements have facilitated correlation of the SFS and IR-ATR findings with the interaction of the polymer and surfactant at the hydrophobic air/water interface.