Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL, USA.
Department of Mechanical and Industrial Engineering, University of Illinois Chicago, Chicago, IL, USA.
Nanoscale. 2023 Apr 13;15(15):7006-7013. doi: 10.1039/d3nr00097d.
The study of ice nucleation and growth at the nanoscale is of utmost importance in geological and atmospheric sciences. However, existing transmission electron microscopy (TEM) approaches have been unsuccessful in imaging ice formation directly. Herein, we demonstrate how radical scavengers - such as TiO - encased with water in graphene liquid cells (GLCs) facilitate the observation of ice nucleation phenomena at low temperatures. Atomic-resolution imaging reveals the nucleation and growth of cubic ice-phase crystals at close proximity to TiO-water nanointerfaces at low temperatures. Interestingly, both heterogeneously and homogeneously nucleated ice crystals exhibited this cubic phase. Ice crystal nuclei were observed to be more stable at the TiO-water nanointerface, as compared with crystals in the bulk liquid (homogeneous nucleation), suggesting the radical scavenging efficacy of TiO nanoparticles mitigating the electron beam by-products. The present work demonstrates that the use of radical scavengers in GLC TEM shows great promise towards unveiling the nanoscale pathways for ice nucleation and growth dynamic events.
纳米尺度上的冰成核和生长研究在地质和大气科学中至关重要。然而，现有的透射电子显微镜（TEM）方法在直接成像冰形成方面一直不成功。在此，我们展示了自由基清除剂（如 TiO）如何在含石墨烯液体池（GLC）中的水包裹下促进低温下冰成核现象的观察。原子分辨率成像揭示了在低温下接近 TiO-水纳米界面处立方冰相晶体的成核和生长。有趣的是，无论是异质成核还是均相成核的冰晶都表现出这种立方相。与体相液体中的晶体（均相成核）相比，在 TiO-水纳米界面处观察到冰晶核更加稳定，这表明 TiO 纳米颗粒的自由基清除效果减轻了电子束的副产物。本工作表明，在 GLC-TEM 中使用自由基清除剂有望揭示冰成核和生长动态事件的纳米尺度途径。
