Characterizing Anion Adsorption to Aqueous Interfaces: Toluene-Water versus Air-Water

Shane W. Devlin, Debra L. McCaffrey, Richard J. Saykally

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We continue our investigation of the behavior of simple ions at aqueous interfaces, employing the combination of two surface-sensitive nonlinear spectroscopy tools, broadband deep UV electronic sum-frequency generation and UV second harmonic generation, to characterize the adsorption of thiocyanate to the interface of water with toluene─a prototypical hydrophobe. We find that both the interfacial spectrum and the Gibbs free energy of adsorption closely match results previously reported for the air-water interface. We observe no relative spectral shift in the higher-energy CTTS transition of thiocyanate, implying similar solvation environments for the two interfaces. Similarly, the Gibbs free energies of adsorption agree within error; however, we expect the respective enthalpic and entropic contributions to differ between the two interfaces, similar to our earlier findings for the air-water versus graphene-water interfaces. Further experiments and theoretical modeling are necessary to quantify the mechanistic differences.
Original languageEnglish (US)
Pages (from-to)222-228
Number of pages7
JournalJournal of Physical Chemistry Letters
Issue number1
StatePublished - Dec 30 2021
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-05-25
Acknowledged KAUST grant number(s): OSR-2019-CPF-4109.3
Acknowledgements: This work was supported by the Department of Energy, Office of Basic Energy Sciences, through the Chemical Sciences Division at the Lawrence Berkeley National Laboratory under contract #CH403503, through King Abdullah University of Science and Technology (KAUST) under contract #OSR-2019-CPF-4109.3, and through the ACS Petroleum Research Fund under grant #59408-ND6
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • General Materials Science


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