Direct Observations of the Rotation and Translation of Anisotropic Nanoparticles Adsorbed at a Liquid-Solid Interface
Direct Observations of the Rotation and Translation of Anisotropic Nanoparticles Adsorbed at a Liquid-Solid Interface
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DOI：
10.1021/acs.nanolett.8b04962
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发表时间：
2019-05-01
期刊：
影响因子：
10.8
通讯作者：
Mirsaidov, Utkur
中科院分区：
文献类型：
--
作者：
Chee, See Wee;Anand, Utkarsh;Mirsaidov, Utkur
我们可以通过跟踪纳米粒子的运动来了解它们在溶液和固体表面之间的相互作用。在这里，我们使用液体细胞透射电子显微镜（TEM）直接跟踪以每秒300帧的速率吸附在SiNx表面上的金纳米金字塔（nbp）和纳米棒（NRs）的平移和旋转。这项研究的动机是长期需要详细描述液体电池TEM中这一共同表面上的NP运动。我们将展示NPs在毫秒级的时间尺度上间歇性移动。首先，它们以两种方式旋转：(1)围绕质心旋转；(2)在尖端旋转。这些旋转也导致了不同的平移模式。NP可以沿着大致平行于其身体轴的方向进行小位移（洗牌），也可以通过多个尖端旋转进行较大的移动。轨迹分析表明，位移和旋转角度均服从重尾幂律分布，意味着异常扩散。我们的方法所提供的空间和时间分辨率也揭示了不同NPs之间的差异。50 nm的NRs和100 nm的nbp在电子束照射后以洗刷和旋转介导的位移相结合的方式移动。随着电子影响的增加，50 nm核磁共振也开始通过解吸介导的跳跃运动。70 nm的核磁共振不表现出平移运动，只进行小的旋转。这些结果描述了NP动力学在电子束作用下的演化过程，以及固体表面特定吸附位点上的间歇性钉钉和释放如何控制液固界面上的NP运动。我们还讨论了SiNx表面处理对NP运动的影响，展示了我们的方法如何为界面传输提供更广泛的见解。
We can learn about the interactions between nanoparticles (NPs) in solution and solid surfaces by tracking how they move. Here, we use liquid cell transmission electron microscopy (TEM) to follow directly the translation and rotation of Au nanobipyramids (NBPs) and nanorods (NRs) adsorbed onto a SiNx surface at a rate of 300 frames per second. This study is motivated by the enduring need for a detailed description of NP motion on this common surface in liquid cell TEM. We will show that NPs move intermittently on the time scales of milliseconds. First, they rotate in two ways: (1) rotation around the center of mass and (2) pivoted rotation at the tips. These rotations also lead to different modes of translation. A NP can move through small displacements in the direction roughly parallel to its body axis (shuffling) or with larger steps via multiple tip-pivoted rotations. Analysis of the trajectories indicates that both displacements and rotation angles follow heavy-tailed power law distributions, implying anomalous diffusion. The spatial and temporal resolution afforded by our approach also revealed differences between the different NPs. The 50 nm NRs and 100 nm NBPs moved with a combination of shuffles and rotation-mediated displacements after illumination by the electron beam. With increasing electron fluence, 50 nm NRs also started to move via desorption-mediated jumps. The 70 nm NRs did not exhibit translational motion and only made small rotations. These results describe how NP dynamics evolve under the electron beam and how intermittent pinning and release at specific adsorption sites on the solid surface control NP motion at the liquid-solid interface. We also discuss the effect of SiNx surface treatment on NP motion, demonstrating how our approach can provide broader insights into interfacial transport.