Phase Transition Behavior of Fluorinated Monolayers at the Water−Hexane Interface

X-ray surface scattering and interfacial tension measurements are used to study the solid-to-gas phase transition in soluble monolayers of F(CF 2 ) 8 (CH 2 ) 2 OH and F(CF 2 ) 10 (CH 2 ) 2 OH adsorbed at the water−hexane interface. X-ray reflectivity and diffuse scattering measurements determine the molecular ordering, the presence of domains, and the interfacial coverage of solid domains as a function of temperature. The temperature-dependent coverage can be analyzed by a functional form consistent with a critical transition proposed by theory.