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The surface affinity of cations depends on both the cations and the nature of the surface.

Sudipta DasMischa BonnEllen H G Backus
Published in: The Journal of chemical physics (2019)
Specific ion effects at interfaces are important for a variety of thermodynamic properties of electrolyte solutions, like surface tension and the phase behavior of surfactants. We report the relative surface affinity of Na+ and D3O+ at both the D2O-air and the sodium dodecyl sulfate (surfactant)-covered D2O surface by studying the alignment of interfacial D2O, using vibrational sum frequency generation spectroscopy. The surface propensity of ions is found to be a function of both the nature of the ion and the nature of the surface. Specifically, for the charged, surfactant-covered interface, Na+ has a higher affinity than D3O+. In contrast, D3O+ has a higher affinity than Na+ at the air-D2O interface. The relative surface affinity of cations thus depends on both details of the cation and the type of interface.
Keyphrases
  • ionic liquid
  • magnetic resonance imaging
  • magnetic resonance
  • high resolution
  • computed tomography
  • single molecule