Verification of universality in strong critical adsorption with three techniques.

Fischer and de Gennes [C. R. Acad. Sci., Ser. B 287, 207 (1978)] suggested that for a mixture which was critical with respect to the demixing phase transition an interfacial adsorption profile would exhibit universal (system independent) scaling behavior. Carpenter et al. [Phys. Rev. E 61, 532 (2000) and references therein] verified this theory with a model which described ellipsometry data previously taken from several critical binary liquid mixtures. Until recently this model had not been verified with other experimental techniques. We describe a successful effort to verify Carpenter's model with data from a neutron reflectometry study of a critical D2O + 3-methylpyridine mixture, as well as an analysis of data from both ellipsometry and x-ray reflectometry from a critical mixture of dodecane + tetrabromoethane.