Department of Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
Nat Commun. 2013;4:2548. doi: 10.1038/ncomms3548.
Carbon nanotubes have long been described as rolled-up graphene sheets. It is only fairly recently observed that longitudinal cleavage of carbon nanotubes, using chemical, catalytical and electrical approaches, unzips them into thin graphene strips of various widths, the so-called graphene nanoribbons. In contrast, rolling up these flimsy ribbons into tubes in a real experiment has not been possible. Theoretical studies conducted by Kit et al. recently demonstrated the tube formation through twisting of graphene nanoribbon, an idea very different from the rolling-up postulation. Here we report the first experimental evidence of a thermally induced self-intertwining of graphene nanoribbons for the preferential synthesis of (7, 2) and (8, 1) tubes within parent-tube templates. Through the tailoring of ribbon's width and edge, the present finding adds a radically new aspect to the understanding of carbon nanotube formation, shedding much light on not only the future chirality tuning, but also contemporary nanomaterials engineering.
碳纳米管一直被描述为卷成的石墨烯片。直到最近才发现，通过化学、催化和电学方法对碳纳米管进行纵向劈开，可以将其解开成各种宽度的薄石墨烯带，即所谓的石墨烯纳米带。相比之下，在实际实验中将这些脆弱的带卷成管是不可能的。最近由 Kit 等人进行的理论研究表明，通过扭转石墨烯纳米带可以形成管，这一想法与卷绕假设非常不同。在这里，我们报告了第一个实验证据，证明在母体管模板中，石墨烯纳米带通过热诱导的自缠绕优先合成（7,2）和（8,1）管。通过对 ribbon 的宽度和边缘进行剪裁，这一发现为理解碳纳米管的形成增加了一个全新的方面，不仅为未来的手性调谐提供了重要线索，也为当代纳米材料工程提供了重要启示。
