Wang Feng, Liu Juewen
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Nanoscale. 2015 Jan 21;7(3):919-23. doi: 10.1039/c4nr05832a.
With the thickness of only a single atomic layer, graphene displays many interesting surface properties. A general observation is that wrinkles are formed on graphene oxide (GO) when it is dried in the presence of adsorbed inorganic nanoparticles. In this case, evaporation induced wrinkling is not an elastic deformation but is permanent. Understanding the nanoscale force of wrinkle formation is important for device fabrication and sensing. Herein, we employ surface functionalized gold nanoparticles (AuNPs) as a model system. All tested AuNPs induced wrinkling, including those capped by DNA, polymers and proteins. The size of AuNPs is less important compared to the properties of solvent. Wrinkle formation is attributed to drying related capillary force acting on the GO surface, and a quantitative equation is derived. After drying, the adsorption affinity between GO and AuNPs is increased due to the increased contact area.
石墨烯仅有单个原子层的厚度，却展现出许多有趣的表面特性。一个普遍的观察结果是，氧化石墨烯（GO）在存在吸附的无机纳米颗粒的情况下干燥时会形成皱纹。在这种情况下，蒸发诱导的起皱不是弹性变形，而是永久性的。理解皱纹形成的纳米级力对于器件制造和传感至关重要。在此，我们采用表面功能化的金纳米颗粒（AuNPs）作为模型系统。所有测试的金纳米颗粒都会诱导起皱，包括那些被DNA、聚合物和蛋白质包覆的颗粒。与溶剂的性质相比，金纳米颗粒的尺寸不太重要。皱纹的形成归因于作用在氧化石墨烯表面的与干燥相关的毛细作用力，并推导出了一个定量方程。干燥后，由于接触面积增加，氧化石墨烯与金纳米颗粒之间的吸附亲和力增强。
