The twisted carbon nanotube story Despite progress in growing single-walled carbon nanotubes of specific size and chirality, the factors that control their growth are still not fully known. Magnin et al. developed a thermodynamic model for the growth of single-walled carbon nanotubes. The model explains the origin of nanotube chirality in terms of the configurational entropy of the nanotube edge. The model should be useful in helping to guide nanotube growth parameters to enhance selectivity. Science, this issue p. 212 Modeling the interface of carbon nanotubes with their seeding catalyst nanoparticle reveals the origin of their chirality. Single-walled carbon nanotubes are hollow cylinders that can grow centimeters long via carbon incorporation at the interface with a catalyst. They display semiconducting or metallic characteristics, depending on their helicity, which is determined during their growth. To support the quest for a selective synthesis, we develop a thermodynamic model that relates the tube-catalyst interfacial energies, temperature, and the resulting tube chirality. We show that nanotubes can grow chiral because of the configurational entropy of their nanometer-sized edge, thus explaining experimentally observed temperature evolutions of chiral distributions. Taking the chemical nature of the catalyst into account through interfacial energies, we derive structural maps and phase diagrams that will guide a rational choice of a catalyst and growth parameters toward a better selectivity.

中文翻译：

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手性单壁碳纳米管的熵驱动稳定性

扭曲的碳纳米管的故事 尽管在生长特定尺寸和手性的单壁碳纳米管方面取得了进展，但控制其生长的因素仍不完全清楚。马格宁等人。开发了单壁碳纳米管生长的热力学模型。该模型根据纳米管边缘的构型熵解释了纳米管手性的起源。该模型应该有助于指导纳米管生长参数以提高选择性。科学，这个问题 p。212 模拟碳纳米管与其种子催化剂纳米颗粒的界面，揭示了其手性的起源。单壁碳纳米管是空心圆柱体，通过在催化剂界面处掺入碳，可以长出数厘米长。它们显示出半导体或金属特性，取决于它们的螺旋度，这是在它们的生长过程中决定的。为了支持对选择性合成的探索，我们开发了一个热力学模型，该模型将管催化剂界面能、温度和由此产生的管手性联系起来。我们表明纳米管可以生长手性，因为它们的纳米尺寸边缘的构型熵，从而解释了实验观察到的手性分布的温度演变。通过界面能将催化剂的化学性质考虑在内，我们推导出结构图和相图，这些图和相图将指导催化剂和生长参数的合理选择，以获得更好的选择性。我们开发了一个热力学模型，该模型将管催化剂界面能、温度和由此产生的管手性联系起来。我们表明纳米管可以生长手性，因为它们的纳米尺寸边缘的构型熵，从而解释了实验观察到的手性分布的温度演变。通过界面能将催化剂的化学性质考虑在内，我们推导出结构图和相图，这些图和相图将指导催化剂和生长参数的合理选择，以获得更好的选择性。我们开发了一个热力学模型，该模型将管催化剂界面能、温度和由此产生的管手性联系起来。我们表明纳米管可以生长手性，因为它们的纳米尺寸边缘的构型熵，从而解释了实验观察到的手性分布的温度演变。通过界面能将催化剂的化学性质考虑在内，我们推导出结构图和相图，这些图和相图将指导催化剂和生长参数的合理选择，以获得更好的选择性。