Fukumo, MasafumiYano, Yohko F.Pershan, Peter2013-02-282005Fukumo, Masafumi, Yohko F. Yano, and Peter S. Pershan. 2005. Critical Casimir effect in three-dimensional Ising systems: Measurements on binary wetting films. Physical Review Letters 94(135702).0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:10354245The critical Casimir force (CF) is observed in thin wetting films of a binary liquid mixture close to the liquid/vapor coexistence. X-ray reflectivity shows thickness (L) enhancement near the bulk consolute point. The extracted Casimir amplitude \(\Delta_{+-}\)=3\(\pm\)1 agrees with the theoretical universal value for the antisymmetric 3D Ising films. The onset of CF in the one-phase region occurs at L/\(\xi \sim\)5 regardless of whether the bulk correlation length \(\xi\) is varied with temperature or composition. The shape of the Casimir scaling function depends monotonically on the dimensionality.en-USJournal Article10.1103/PhysRevLett.94.135702