Marathianos Arkadios, Magiakos Alexandros, Han Yisong, Sanchez Ana, Whitfield Richard, Kammerer Jochen, Anastasaki Athina, Wilson Paul, Patterson Joseph P, Barner-Kowollik Christopher, Liarou Evelina
Polymer Characterization Research Technology Platform, University of Warwick, Coventry CV4 7AL, United Kingdom.
Department of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, U.K.
J Am Chem Soc. 2024 Dec 18;146(50):34292-34297. doi: 10.1021/jacs.4c13812. Epub 2024 Dec 4.
Polymer design requires fine control over syntheses and a thorough understanding of their macromolecular structure. Herein, near-atomic level imaging of polymers is achieved, enabling the precise determination of one of the most important macromolecular characteristics: molecular weight. By judiciously designing and synthesizing different linear metal(loid)-rich homopolymers, subnanoscale polymer imaging is achieved through annular dark field-scanning transmission electron microscopy (ADF-STEM), owing to the incorporation of high atoms in the side chain of the monomeric units. The molecular weight of these polymers can be precisely determined by detecting and counting their metal(loid) atoms upon ADF-STEM imaging, at sample concentrations as low as 10 μg·mL. Notably, a commonly used C, H, and O-containing polymer (, poly(methyl acrylate)) that was thus far inaccessible at the atomic scale is derivatized to allow for subnano-level imaging, thus expanding the scope of our approach toward the atomic-level visualization of commodity polymers.
聚合物设计需要对合成过程进行精细控制，并深入了解其大分子结构。在此，实现了聚合物的近原子水平成像，能够精确测定最重要的大分子特征之一：分子量。通过精心设计和合成不同的富含线性金属（类金属）的均聚物，借助环形暗场扫描透射电子显微镜（ADF-STEM）实现了亚纳米级聚合物成像，这是由于在单体单元的侧链中引入了重原子。在ADF-STEM成像时，通过检测和计数这些聚合物的金属（类金属）原子，能够精确测定其分子量，样品浓度低至10μg·mL。值得注意的是，一种迄今为止在原子尺度上无法实现成像的常用含C、H和O的聚合物（聚甲基丙烯酸甲酯）经过衍生化处理后能够实现亚纳米级成像，从而扩展了我们对商品聚合物进行原子级可视化的方法范围。
