What x rays can tell us about the interfacial profile of water near hydrophobic surfaces

Article

关键词: LIQUID-VAPOR INTERFACE;    REFLECTIVITY MEASUREMENTS;    CAPILLARY WAVES;    DENSITY;    SCATTERING;    ROUGHNESS;    DEPLETION;    METALS;    FORCE;    LAYER;   

DOI  :  10.1103/PhysRevB.88.035431

来源: SCIE

【 摘 要 】

The free surface of water and the interface between water and a hydrophobic surface both have positive interface energies. The water density near a free surface drops below the bulk density, and thus it is expected that water near a hydrophobic surface will also show a density depletion. However, efforts by multiple groups to detect and characterize the predicted gap at water-hydrophobic interfaces have produced contradictory results. We have studied the interface between water and fluoroalkylsilane self-assembled monolayers using specular x-ray reflectivity and analyzed the parameter-space landscapes of the merit functions being minimized by data fitting. This analysis yields a better understanding of confidence intervals than the customary process of reporting a unique best fit. We conclude that there are unambiguous gaps at water-hydrophobic interfaces when the hydrophobic monolayer is more densely packed.

【 授权许可】

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