Joo Yongho, Spalenka Josef W, McElhinny Kyle M, Schmitt Samantha K, Evans Paul G, Gopalan Padma
Department of Materials Science and Engineering, and ‡Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States.
Langmuir. 2014 Jun 3;30(21):6104-13. doi: 10.1021/la5006133. Epub 2014 May 22.
We demonstrate the Langmuir-Blodgett assembly of two rhenium-bipyridine complexes containing a flexible or an aromatic bridge, and transfer of the monolayer to SiO2 and single crystal TiO2 substrates. Both of the complexes (ReEC and Re2TC) have a hydrophilic carboxylic acid group, which preferentially anchors into the water subphase, and forms stable monolayers at surface pressures up to 40 mN/m. The optimum conditions for the formation of complete monolayers of both ReEC and Re2TC were identified through characterization of the morphology by atomic force microscopy (AFM), the thickness by ellipsometry, and the surface coverage by X-ray photoelectron spectroscopy (XPS). X-ray reflectivity measurements (XRR) are consistent with the orientation of the molecules normal to the substrate, and their extension to close to their calculated maximum length. Parameters derived from XRR analysis show that there is a higher packing density for Re2TC monolayers than for ReEC monolayers, attributable to the more rigid bridge in the Re2TC molecule.
我们展示了两种含有柔性桥或芳香桥的铼联吡啶配合物的朗缪尔-布洛杰特组装，以及将单层转移到二氧化硅和单晶二氧化钛衬底上。两种配合物（ReEC和Re2TC）都有一个亲水性羧酸基团，该基团优先锚定在水亚相中，并在高达40 mN/m的表面压力下形成稳定的单层。通过原子力显微镜（AFM）表征形态、椭偏仪测量厚度以及X射线光电子能谱（XPS）测量表面覆盖率，确定了形成ReEC和Re2TC完整单层的最佳条件。X射线反射率测量（XRR）与分子垂直于衬底的取向一致，并且它们延伸至接近其计算的最大长度。XRR分析得出的参数表明，Re2TC单层的堆积密度高于ReEC单层，这归因于Re2TC分子中更刚性的桥。
