The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States.
J Am Chem Soc. 2012 Dec 19;134(50):20234-7. doi: 10.1021/ja3091214. Epub 2012 Dec 10.
We describe a synthesis of Au wavy nanowires in an aqueous solution in the presence of cetyltrimethylammonium bromide (CTAB). The resultant Au nanowires automatically separated from the solution and floated at the air/water interface. We investigated the formation mechanism by characterizing the samples obtained at different stages of the synthesis. Both particle attachment and cold welding were found to be involved in the formation of such nanowires. Based on X-ray photoelectron spectroscopy and thermogravimetric analysis, the CTAB molecules adsorbed on the surface of a Au nanostructure went through a change in structure from a bilayer to a monolayer, converting the Au surface from hydrophilic to hydrophobic. As a result, the Au wavy nanowires were driven to the air/water interface during the synthesis. This growth mechanism is potentially extendable to many other systems involving small surfactant molecules.
我们描述了在十六烷基三甲基溴化铵（CTAB）存在下的 Au 波浪形纳米线在水溶液中的合成。所得的 Au 纳米线自动从溶液中分离出来并漂浮在空气/水界面上。我们通过对合成过程中不同阶段获得的样品进行表征，研究了其形成机制。结果表明，颗粒附着和冷焊都参与了纳米线的形成。基于 X 射线光电子能谱和热重分析，吸附在 Au 纳米结构表面的 CTAB 分子的结构从双层转变为单层，使 Au 表面从亲水变为疏水。结果，Au 波浪形纳米线在合成过程中被驱动到空气/水界面。这种生长机制可能会扩展到许多其他涉及小分子表面活性剂的系统。
