Cryo-SEM specimen preparation under controlled temperature and concentration conditions
Cryo-SEM specimen preparation under controlled temperature and concentration conditions
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DOI：
10.1111/j.1365-2818.2011.03587.x
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发表时间：
2012-04-01
影响因子：
2
通讯作者：
Talmon, Y.
中科院分区：
文献类型：
--
作者：
Issman, L.;Talmon, Y.
低温扫描电子显微镜（cryo-SEM）是对高蒸汽压的液体和半液体材料成像的一种极好的技术，这些材料是高粘性的或含有大的（>0.5 μ m）聚集体，其中纳米细节有待研究。然而，到目前为止，还没有足够的工具来控制冷冻标本的制备。样品制备阶段至关重要，因为这些样品中的大多数对浓度和温度变化非常敏感，导致样品中的纳米结构伪影。我们设计并建立了一个系统，用于在固定温度和湿度的受控条件下轻松可靠地制备低温SEM样品。我们描述了这种新的方法，并证明其适用性，通过显示三种液体材料系统的成像数据。我们研究了碳纳米管在超强酸中的分散。我们还表征了一些由水/异辛烷/非离子和阳离子表面活性剂制成的系统，其显示出不同的微乳液相作为系统组合物和温度的函数。在所有给出的例子中，我们展示了无人工制品和无污染的标本，这些标本保留了它们的天然纳米结构。我们的新系统为新兴的低温SEM领域的新方法铺平了道路。
Cryogenic temperature scanning electron microscopy (cryo-SEM) is an excellent technique for imaging liquid and semi-liquid materials of high vapour pressure, which are highly viscous or contain large (>0.5 mu m) aggregates, in which nanometric details are to be studied. However, so far there have been no adequate tools for controlled cryo-specimen preparation. The specimen preparation stage is critical, because most of those samples are very sensitive to concentration and temperature changes, leading to nanostructural artefacts in the specimens. We designed and built a system for easy and reliable cryo-SEM specimen preparation under controlled conditions of fixed temperature and humidity. We describe this new methodology, and demonstrate its applicability, by showing imaging data of three liquid material systems. We have studied carbon nanotubes (CNTs) dispersions in superacid. We also characterized a number of systems made of water/isooctane/nonionic and cationic surfactant that showed different microemulsion phases as function of the system composition and temperature. In all of the examples given, we demonstrate artefact- and contamination-free specimens, which have preserved their native nanostructure. Our new system paves the way for a new methodology for the newly emerging field of cryo-SEM.