Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
J Phys Chem B. 2010 Oct 7;114(39):12549-57. doi: 10.1021/jp105114d.
A series of partially fluorinated aliphatic thioethers of the following formula: CF(3)-(CF(2))(7)-(CH(2))(10)-S-C(n)H(2n+1), where n = 1, 2, 4, 8, 12, and 18, were synthesized and spread from chloroform solution onto the water/air interface in a Langmuir trough. Upon compression of the film, the surface pressure-mean molecular area isotherms were recorded. It turned out that all the investigated compounds are capable of stable Langmuir monolayers formation. The electrical properties of the studied monolayers have been investigated by monitoring the change in the surface potential (ΔV) upon film compression. The performed experiments proved that regardless of the length of the C(n)H(2n+1) chain, the orientation of the film molecules is very similar. The investigated monolayers have been visualized applying Brewster angle microscopy. The monolayers of the shorter homologues turned out to be homogeneous until their collapse, whereas for longer homologues, the formation of multilayer aggregates was observed. The methods of grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XR) have also been applied for the characterization of the organization of thioether molecules in their monolayers. The GIXD experiments proved that the films of the studied thioethers possess a periodical in-plane structure. They are collectively tilted toward the next neighbor (NN tilt), and their packing within the monolayer (xy) plane can be described by the 2-dimentional rectangular centered lattice. Interpretation of the XR results indicate that only the partially fluorinated chain of the thioether molecule is periodically organized at the water/air interface, whereas the hydrocarbon chain is disordered and has a liquid character.
一系列通式为 CF(3)-(CF(2))(7)-(CH(2))(10)-S-C(n)H(2n+1) 的部分氟化脂肪族硫醚被合成，并从氯仿溶液中扩散到 Langmuir 槽中的水/气界面上。在压缩薄膜时，记录表面压力-平均分子面积等温线。结果表明，所有研究的化合物都能够形成稳定的 Langmuir 单层。通过监测薄膜压缩时表面电势（ΔV）的变化来研究研究的单层的电特性。进行的实验证明，无论 C(n)H(2n+1)链的长度如何，薄膜分子的取向非常相似。应用掠入射 X 射线衍射（GIXD）和 X 射线反射率（XR）方法也对硫醚分子在单层中的组织进行了表征。GIXD 实验证明，所研究的硫醚的薄膜具有周期性的面内结构。它们集体向相邻层倾斜（NN 倾斜），并且它们在单层（xy）平面内的堆积可以用二维矩形中心晶格来描述。对 XR 结果的解释表明，只有硫醚分子的部分氟化链在水/气界面上周期性地组织，而烃链是无序的，具有液体性质。
