title: Salty glycerol versus salty water surface organization: bromide and iodide surface propensities.
abstract: Salty NaBr and NaI glycerol solution interfaces are examined in the OH stretching region using broadband vibrational sum frequency generation (VSFG) spectroscopy. Raman and infrared (IR) spectroscopy are used to further understand the VSFG spectroscopic signature. The VSFG spectra of salty glycerol solutions reveal that bromide and iodide anions perturb the interfacial glycerol organization in a manner similar as that found in aqueous halide salt solutions, thus confirming the presence of bromide and iodide anions at the glycerol surface. Surface tension measurements are consistent with the surface propensity suggested by the VSFG data and also show that the surface excess increases with increasing salt concentration, similar to that of water. In addition, iodide is shown to have more surface prevalence than bromide, as has also been determined from aqueous solutions. These results suggest that glycerol behaves similarly to water with respect to surface activity and solvation of halide anions at its air/liquid interface.
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
authors.forename: Zishuai
authors.initials: Z
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.forename: Dominique
authors.initials: D
authors.lastname: Verreault
authors.forename: Heather C
authors.initials: HC
authors.lastname: Allen