The direction and magnitude of surface dipoles directly affect the interfacial properties and can be tuned through molecular design. This article examines the effect of a hydrocarbon–fluorocarbon, “HC–FC”, dipole on the structural and interfacial properties of self-assembled monolayers (SAMs) as the dipole is buried into the film. A series of selectively fluorinated alkanethiols with a progressively extended alkyl chain atop six fluorocarbons and an alkyl spacer of 11 hydrocarbons, H(CH₂)_n(CF₂)₆(CH₂)₁₁SH, where n = 1–7 (HnF6H11SH) were prepared and used to generate SAMs on evaporated gold, allowing for the systematic burying of the HC–FC dipole into the film. Structural analyses of the films revealed well-ordered films with slight disorder/loose packing in the top alkyl chains. In addition, odd–even effects were observed in the orientation and wettability of the SAMs corresponding to the number of carbon atoms in the top alkyl chain, leading to the conclusion that the fluorinated segment behaves as a surrogate surface. As for the effect of the dipole on the wetting behavior of the films, the effect appears to be minimized after three methylene units; however, the structural features of the monolayers were also found to influence the wettability of the films.

中文翻译：

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掩埋倒置的表面偶极子：烷基末端部分氟化的烷硫醇衍生自组装的单层。

表面偶极子的方向和大小直接影响界面性质，可以通过分子设计进行调整。本文研究了偶极子埋入薄膜中时，碳氢化合物-碳氟化合物（HC-FC）偶极子对自组装单分子层（SAMs）的结构和界面特性的影响。一系列选择性氟化的链烷硫醇，在六个碳氟化合物上具有逐渐延伸的烷基链，并具有11个烃的烷基间隔基，H（CH ₂）_n（CF ₂）₆（CH ₂）₁₁ SH，其中n = 1–7（HnF6H11SH）的制备，并用于在蒸发的金上生成SAM，从而将HC-FC偶极子有系统地掩埋在薄膜中。薄膜的结构分析表明，排列整齐的薄膜在顶部烷基链中具有轻微的无序/松散堆积。此外，在SAM的方向和润湿性中观察到奇偶效应，与顶部烷基链中的碳原子数相对应，从而得出结论，氟化链段具有替代表面的作用。至于偶极子对薄膜的润湿行为的影响，在三个亚甲基单元后，该影响似乎被最小化了。然而，还发现单层的结构特征影响膜的润湿性。