Mixing in Adsorbed Monolayers:  Perfluorinated Alkanes

DOI: 10.1021/la703995u

Authors: S. M. Clarke (University of Cambridge) , J. E. Parker (University of Cambridge)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Langmuir , VOL 24(9) , PAGES 4833-4844

State: Published (Approved)
Published: April 2008

Abstract: The mixing behavior of binary combinations of perfluoroalkanes in the bulk and in solid monolayers adsorbed at the graphite/liquid interface, determined by calorimetry and powder diffraction, is reported. The perfluoroalkanes are found to generally have a smaller excess enthalpy of mixing on the surface than in the bulk, and their relative size ratio is a good parameter to predict the mixing behavior. The excess enthalpy of mixing for perfluoroalkanes is found to be significantly smaller than that of the closely related hydrocarbons. The preferential adsorption of longer homologues over shorter ones is observed. Interestingly, the extent of preferential adsorption with relative size ratio is very similar to that of the hydrocarbons. These results can be understood in terms of the increased compressibility and lower polarizability of the perfluoroalkanes compared to hydrocarbons.

Subject Areas: Chemistry


Instruments: NONE-No attached Diamond beamline

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