Mougin K, Gnecco E, Rao A, Cuberes M T, Jayaraman S, McFarland E W, Haidara H, Meyer E
ICSI-Centre National de la Recherche Scientifique, 15 Rue Jean Starcky, Mulhouse, France.
Langmuir. 2008 Feb 19;24(4):1577-81. doi: 10.1021/la702921v. Epub 2008 Jan 18.
We have manipulated raw and functionalized gold nanoparticles (with a mean diameter of 25 nm) on silicon substrates with dynamic atomic force microscopy (AFM). Under ambient conditions, the particles stick to silicon until a critical amplitude is reached by the oscillations of the probing tip. Beyond that threshold, the particles start to follow different directions, depending on their geometry and adhesion to the substrate. Higher and lower mobility were observed when the gold particles were coated with methyl- and hydroxyl-terminated thiol groups, respectively, which suggests that the adhesion of the particles to the substrate is strongly reduced by the presence of hydrophobic interfaces. Under ultrahigh vacuum conditions, where the water layer is absent, the particles did not move, even when operating the atomic force microscope in contact mode. We have also investigated the influence of the temperature (up to 150 degrees C) and of the geometrical arrangement of the particles on the manipulation process. Whereas thermal activation has an important effect in enhancing the mobility of the particles, we did not find differences when manipulating ordered versus random distributions of particles.
我们使用动态原子力显微镜（AFM）在硅基衬底上操控了原始的和功能化的金纳米颗粒（平均直径为25纳米）。在环境条件下，颗粒会附着在硅上，直到探测针尖的振荡达到临界振幅。超过该阈值后，颗粒会根据其几何形状和与衬底的附着力开始朝不同方向移动。当金颗粒分别被甲基封端和羟基封端的硫醇基团包覆时，观察到了较高和较低的迁移率，这表明疏水界面的存在会大大降低颗粒与衬底的附着力。在不存在水层的超高真空条件下，即使以接触模式操作原子力显微镜，颗粒也不会移动。我们还研究了温度（高达150摄氏度）和颗粒几何排列对操控过程的影响。虽然热激活在增强颗粒迁移率方面有重要作用，但在操控颗粒的有序分布和随机分布时，我们并未发现差异。
