Juhl Stephen J, Wang Tao, Vermilyea Brian, Li Xiang, Crespi Vincent H, Badding John V, Alem Nasim
J Am Chem Soc. 2019 May 1;141(17):6937-6945. doi: 10.1021/jacs.8b13405. Epub 2019 Apr 22.
Carbon nanothreads are a new one-dimensional sp-bonded nanomaterial of CH stoichiometry synthesized from benzene at high pressure and room temperature by slow solid-state polymerization. The resulting threads assume crystalline packing hundreds of micrometers across. We show high-resolution electron microscopy (HREM) images of hexagonal arrays of well-aligned thread columns that traverse the 80-100 nm thickness of the prepared sample. Diffuse scattering in electron diffraction reveals that nanothreads are packed with axial and/or azimuthal disregistry between them. Layer lines in diffraction from annealed nanothreads provide the first evidence of translational order along their length, indicating that this solid-state reaction proceeds with some regularity. HREM also reveals bends and defects in nanothread crystals that can contribute to the broadening of their diffraction spots, and electron energy-loss spectroscopy confirms them to be primarily sp-hybridized, with less than 27% sp carbon, most likely associated with partially saturated "degree-4" threads.
碳纳米线是一种新型的一维sp键合纳米材料，其化学计量比为CH，通过在高压和室温下由苯进行缓慢的固态聚合反应合成。生成的纳米线呈现出数百微米宽的晶体堆积。我们展示了排列良好的线柱六边形阵列的高分辨率电子显微镜（HREM）图像，这些线柱贯穿制备样品80 - 100纳米的厚度。电子衍射中的漫散射表明，纳米线之间存在轴向和/或方位角的无序排列。退火纳米线衍射中的层线提供了沿其长度方向平移有序的首个证据，表明这种固态反应以一定的规律性进行。HREM还揭示了纳米线晶体中的弯曲和缺陷，这些可能导致其衍射斑点变宽，并且电子能量损失谱证实它们主要是sp杂化的，sp碳含量低于27%，最有可能与部分饱和的“四级”线相关。
