Graphitic cones and the nucleation of curved carbon surfaces
Graphitic cones and the nucleation of curved carbon surfaces
复制标题
DOI：
10.1038/41284
复制
发表时间：
1997-07-31
期刊：
影响因子：
64.8
通讯作者：
Ebbesen, TW
中科院分区：
文献类型：
--
作者：
Krishnan, A;Dujardin, E;Ebbesen, TW
弯曲碳结构的成核和生长，如富勒烯，纳米管和烟灰，仍然没有得到很好的理解。已经提出了各种各样的模型（1-17），很明显，五边形的出现，在六方石墨网络中产生60度的向错缺陷，是这个难题的关键因素。成核问题由于在任何一个样品中观察到的各种各样的结构而变得复杂。在这里，我们报告了一个不寻常的碳样品产生的烃类热解，完全由石墨微观结构与总向错是+60度的倍数。每个结构的向错对应于种子中存在的给定数量的五边形：圆盘（没有五边形），五种类型的锥体（1到5个五边形），其中只有一种是以前已知的（18），以及开放的管（6个五边形）。对这些区域的统计分析显示了一些意想不到的特征，这表明熵在向错的形成中起着主导作用。此外，畴的总向错主要在成核阶段决定。
The nucleation and growth of curved carbon structures, such as fullerenes, nanotubes and soot, are still not well understood. A variety of models have been proposed(1-17), and it seems clear that the occurrence of pentagons, which yield 60 degrees disclination defects in the hexagonal graphitic network, is a key element in the puzzle. The problem of nucleation has been complicated by the great variety of structures observed in any one sample. Here we report an unusual carbon sample generated by pyrolysis of hydrocarbons, consisting entirely of graphitic microstructures with total disclinations that are multiples of +60 degrees. The disclination of each structure corresponds to the presence of a given number of pentagons in the seed from which it grew: disks (no pentagons), five types of cones (one to five pentagons), of which only one was known previously(18), and open tubes (six pentagons). Statistical analysis of these domains shows some unexpected features, which suggest that entropy plays a dominant role in the formation of disclinations. Furthermore, the total disclination of a domain is determined mainly at the nucleation stage.