Individual macromolecules of polystyrene sulfonate and poly(ethylene oxide) are visualized with nanometer resolution using transmission electron microscopy (TEM) imaging of aqueous solutions with and without added salt, trapped in liquid pockets between creased graphene sheets. Successful imaging with 0.3 s per frame is enabled by the sluggish mobility of the adsorbed molecules. This study finds, validating others, that an advantage of this graphene liquid‐cell approach is apparently to retard sample degradation from incident electrons, in addition to minimizing background scattering because graphene windows are atomically thin. Its new application here to polymers devoid of metal‐ion labeling allows the projected sizes and conformational fluctuations of adsorbed molecules and adsorption–desorption events to be analyzed. Confirming the identification of the observed objects, this study reports statistical analysis of datasets of hundreds of images for times up to 100 s, with variation of the chemical makeup of the polymer, the molecular weight of the polymer, and the salt concentration. This observation of discrete polymer molecules in solution environment may be useful generally, as the findings are obtained using an ordinary TEM microscope, whose kind is available to many researchers routinely.

中文翻译：

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吸附聚合物的液池电子显微镜

聚苯乙烯磺酸盐和聚环氧乙烷的单个大分子使用透射电子显微镜（TEM）成像，在有或没有添加盐的情况下，被困在折皱的石墨烯片之间的液体囊中，以纳米分辨率可视化。吸附分子的缓慢迁移使每帧0.3 s的成功成像成为可能。这项研究证实了其他观点，该石墨烯液体电池方法的一个优势是，除了由于石墨烯窗口原子薄而使背景散射最小化之外，还可以最大程度地抑制样品因入射电子而降解。它在没有金属离子标记的聚合物上的新应用可以分析吸附分子的预计大小和构象波动以及吸附解吸事件。为了确定所观察对象的识别，本研究报告了长达100 s的数百幅图像数据集的统计分析，其中聚合物的化学组成，聚合物的分子量和盐浓度发生了变化。在溶液环境中观察离散聚合物分子通常可能有用，因为这些发现是使用普通TEM显微镜获得的，该显微镜通常可用于许多研究人员。