Kunnas Peter, de Jonge Niels, Patterson Joseph P
University of Vienna, Faculty of Physics, VCQ, Vienna A-1090, Austria; University of Vienna, Max Perutz Laboratories, Department of Structural and Computational Biology, Vienna A-1030, Austria.
Leibniz Institute for New Materials, Saarbrücken, Germany; Department of Physics, Saarland University, Saarbrücken, Germany; Bruker AXS, Karlsruhe, Germany.
Ultramicroscopy. 2024 Jan;255:113865. doi: 10.1016/j.ultramic.2023.113865. Epub 2023 Oct 5.
Liquid cell transmission electron microscopy is a powerful tool for visualizing nanoparticle (NP) assemblies in liquid environments with nanometer resolution. However, it remains a challenge to control the NP concentration in the high aspect ratio liquid enclosure where the diffusion of dispersed NPs is affected by the exposed surface of the liquid cell walls. Here, we introduce a semi-empirical model based on the 1D diffusion equation, to predict the NP loading time as they pass through the nanochannel into the imaging volume of the liquid cell. We show that loading of NPs into the imaging volume of the liquid cell may take several days if NPs are prone to attach to the surface of the mm-long nanochannel when using an industry-standard flat microchip. As a means to facilitate mass transport via diffusion, we tested a liquid cell incorporating a microchannel geometry resulting in a NP loading time in the order minutes that allowed us to observe the formation of a randomly oriented self-assembled monolayer in situ using scanning transmission electron microscopy.
液体池透射电子显微镜是一种强大的工具，可在液体环境中以纳米分辨率可视化纳米颗粒（NP）组装体。然而，在高纵横比的液体容器中控制NP浓度仍然是一项挑战，在这种容器中，分散的NP的扩散受到液体池壁暴露表面的影响。在这里，我们引入了一个基于一维扩散方程的半经验模型，以预测NP通过纳米通道进入液体池成像体积时的加载时间。我们表明，如果在使用行业标准的平面微芯片时NP易于附着在毫米长的纳米通道表面上，将NP加载到液体池的成像体积中可能需要几天时间。作为促进通过扩散进行质量传输的一种手段，我们测试了一种包含微通道几何结构的液体池，其NP加载时间为几分钟，这使我们能够使用扫描透射电子显微镜原位观察随机取向的自组装单层的形成。
