Micro- and nanoplastics (MNPs) are considered a possible threat to microorganisms in the aquatic environment. Here, we show that total scattering intensity analysis of electron diffraction (ED) data measured by transmission electron microscopy, which yields the electron pair distribution function (ePDF), is a feasible method for the characterization and identification of MNPs down to 100 nm. To demonstrate the applicability, cryo ball-milled powders of the most common polymers [i.e., polyethylene , polypropylene, polyethylene terephthalate, and polyamide] and nano-sized polystyrene and silica spheres were used as model systems. The comparison of the experimentally determined reduced pair density functions (RDFs) with model RDFs derived from crystallographic data of the respective polymers allows the distinction of the different types of polymers. Furthermore, carbon-based polymers are highly beam-sensitive materials. The degradation of the samples under the electron beam was analyzed by conducting time-resolved ED measurements. Changes in the material can be visualized by the RDF analysis of the time-series of ED patterns, and information about the materials in question can be gained by this beam damage analysis. Prospectively, ePDF analytics will help to understand and study more precisely the input of MNPs into the environment.

中文翻译：

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通过透射电子显微镜 (ePDF) 中的成对分布函数分析，对微米和纳米塑料颗粒的剂量率依赖性光束引起的结构变化进行结构识别和观察。

微米和纳米塑料（MNP）被认为对水生环境中的微生物可能构成威胁。在这里，我们表明，对透射电子显微镜测量的电子衍射（ED）数据进行总散射强度分析，产生电子对分布函数（ePDF），是表征和识别低至 100 nm 的 MNP 的可行方法。为了证明其适用性，使用最常见聚合物（即聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰胺）的低温球磨粉末以及纳米级聚苯乙烯和二氧化硅球作为模型系统。将实验确定的约化对密度函数 (RDF) 与源自各个聚合物的晶体学数据的模型 RDF 进行比较，可以区分不同类型的聚合物。此外，碳基聚合物是对光束高度敏感的材料。通过进行时间分辨 ED 测量来分析样品在电子束下的降解情况。可以通过 ED 图案时间序列的 RDF 分析来可视化材料的变化，并且可以通过该光束损伤分析获得有关所讨论材料的信息。展望未来，ePDF 分析将有助于更准确地理解和研究 MNP 对环境的输入。