The liquid-liquid phase separation temperatures Tsep for the binary mixtures cyclohexane or perdeuterocyclohexane-perfluorohexane and for the ternary mixture (equivolume cyclohexane-perdeuterocyclohexane)-perfluorohexane have been determined by visual observation. Perdeuteriation of cyclohexane lowers the upper critical solution temperature TUCS from 346.16 to 337.69 K but the shape of the phase diagram in terms of the Wegner extended scaling series is unaltered. In contrast, although the maximum separation temperature of the ternary mixture Tsep,max is little different from TUCS of cyclohexane-perfluorohexane, the shape of the Tsep vs. perfluorohexane mole fraction curve is substantially different. The results cast some doubt on the assumption that the thermodynamics of a solution, and hence the surface structure, in a contrast-matched solvent in reflectivity measurement is the same as would be obtained in the pure solvent.
|Number of pages||8|
|Journal||Journal of the Chemical Society - Faraday Transactions|
|Publication status||Published - 21 Jun 1996|
- ternary mixtures
- liquid–liquid phase separation temperatures