Structural, Electronic, and Mechanical Properties of Single-Walled Halloysite Nanotube Models
Structural, Electronic, and Mechanical Properties of Single-Walled Halloysite Nanotube Models
复制标题
DOI：
10.1021/jp100902e
复制
发表时间：
2010-07-08
影响因子：
3.7
通讯作者：
Duarte, Helio A.
中科院分区：
文献类型：
--
作者：
Guimaraes, Luciana;Enyashin, Andrey N.;Duarte, Helio A.
高岭土是一种粘土矿物，化学计量量为Al2Si2O5(OH)(4)中心点nH(2)O，可以生长成长管状，化学性质与高岭石相似。在这项工作中，我们采用自一致电荷密度-功能紧密结合方法（SCC-DFTB）系统地研究了锯齿形和扶手形单壁高岭土纳米管的稳定性、电子和力学性能。详细分析了结构性能、应变能和带隙随管半径和Mulliken电荷分布的变化规律。高岭土纳米管的应变能不具有单调性，在24埃以上的半径范围内具有最稳定的结构，与实验数据一致。态的电子密度分析表明，所有的电子管都是绝缘体。我们的计算预测，单壁高岭土纳米管的杨氏模量与伊莫高岭土和无机纳米管的杨氏模量相同，但小于碳纳米管的杨氏模量。尽管大多数性质可以用更简单的高岭土模型来充分描述，但对多壁和大直径管的进一步研究仍在进行中。
Halloysite is a clay mineral with stoichiometry Al2Si2O5(OH)(4)center dot nH(2)O that can grow into long tubules and is chemically similar to kaolinite. In this work we present a systematic study on the stability, electronic, and mechanical properties of zigzag and armchair single-walled halloysite nanotubes by means of the self-consistent charge density-functional tight-binding method (SCC-DFTB). The detailed analysis is focused on structural properties, strain energy, and band gap as a function of tube radii and Mulliken charge distribution. The strain energy of halloysite nanotubes does not have a monotonic character and the most stable structures should be observed in the region of radii above 24 angstrom, in agreement with experimental data. Analysis of the electronic density of states shows that all tubes are insulators. Our calculations predict that single-walled halloysite nanotubes have Young modulus in the same order of imogolite and inorganic nanotubes, but smaller than that of carbon nanotubes. Even though most of the properties are adequately described by simpler halloysite models, further studies on multiwalled and larger diameter tubes are in progress.