Measurements of the interfacial tension between nematic and isotropic phase of some cyanobiphenyls

摘要

The interfacial tension ggr;eqbetween nematic and isotropic phases of some cyanobiphenyls has been measured by using the sessile drop method. Values of ggr;eqranging from 0.7times;10minus;2to 1.8times;10minus;2erg/cm2are obtained. In a recent paper we measured the optical reflectivity coefficients at the nematicndash;isotropic interface of 7CB. By using these coefficients and the measured value of ggr;eqwe can obtain the experimental value of the intrinsic thickness of the nematicndash;isotropic interface of 7CB. This thickness is compared with the one predicted by the Landaundash;De Gennes theory. A satisfactory agreement between experimental and theoretical values is found.