Structural Evidence for the Ordered Crystallites of Ionic Liquid in Confined Carbon Nanotubes
Structural Evidence for the Ordered Crystallites of Ionic Liquid in Confined Carbon Nanotubes
复制标题
限域碳纳米管中离子液体有序微晶的结构证据
DOI：
10.1021/jp900533k
复制
发表时间：
2009-06-11
影响因子：
3.7
通讯作者：
Lyubartsev, Alexander
中科院分区：
文献类型：
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作者：
Dong, Kun;Zhou, Guohui;Lyubartsev, Alexander
离子液体(ILS)是近几十年来引起广泛关注的一类新型绿色材料。当离子液体被限制在纳米尺度时，可能会出现许多在正常条件下不明显的新性质。实验中观察到，当1-正丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6])离子液体被限制在碳纳米管中时，出现了从液体到高熔点完美晶体的反常相行为。在这项工作中，我们对[bmim][PF6]离子液体进行了分子动力学(MD)模拟，并提供了离子在碳纳米管中结晶的直接结构证据。在碳纳米管的孔道内可以观察到径向和轴向的有序离子排列，从而诱导出微晶的形成。碳纳米管的大小决定了离子的堆积和分布。当离子液体以氢键形式进入碳纳米管时，阴阳离子间的相互作用仍以氢键为主。
Ionic liquids (ILs) are a class of new green materials that have attracted extensive attention in recent decades. Many novel properties not evident under normal conditions may appear when ionic liquids are confined to a nanometer scale. As was observed in the experiment, an anomalous phase behavior from liquid to high melting point perfect crystal occurred when 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) ionic liquid was confined in a carbon nanotube. In this work, we performed molecular dynamics (MD) simulations for [bmim][PF6] ionic liquid and provided direct structural evidence that the ionic crystallizes in a carbon nanotube. The ordered ionic arrangement in both the radial and the axial directions can be observed inside the channels of the CNTs to induce the form of crystallites. The ionic stacking and distributing can be determined by the sizes of the CNTs. Hydrogen bonds remain the dominant interactions between cations and anions when the ionic liquid enters into the CNT from th...