Hanus Monica J, Harris Andrew T
Laboratory for Sustainable Technology, School of Chemical and Biomolecular Engineering (J01), University of Sydney, NSW 2006, Australia.
J Nanosci Nanotechnol. 2010 Apr;10(4):2261-83. doi: 10.1166/jnn.2010.1912.
Coiled carbon nanotubes are helical carbon structures formed when heptagonal and pentagonal rings are inserted into the hexagonal backbone of a 'straight' nanotube. Coiled carbon nanotubes have been reported with both regular and irregular helical structures. In this work the structure, growth mechanism(s), synthesis, properties and potential applications of coiled carbon nanotubes are reviewed. Published data suggests that coiled carbon nanotube synthesis occurs due to nonuniform extrusion of carbon from a catalyst surface. To date, coiled carbon nanotubes have been synthesised using catalyst modification techniques including: (i) the addition of S or P containing compounds during synthesis; (ii) the use of binary or ternary metal catalysts; (iii) the use of microwaves to create a local temperature gradient around individual catalyst particles and; (iv) the use of pH control during catalyst preparation. In most instances coiled carbon nanotubes are produced as a by-product; high yield and/or large-scale synthesis of coiled carbon nanotubes remains problematic. The qualitative analysis of coiled carbon nanotubes is currently hindered by the absence of specific characterisation data in the literature, e.g., oxidation profiles measured by thermogravimetric analysis and Raman spectra of pure coiled carbon nanotube samples.
卷曲碳纳米管是在七边形和五边形环插入“直”纳米管的六边形骨架时形成的螺旋状碳结构。据报道，卷曲碳纳米管具有规则和不规则的螺旋结构。本文综述了卷曲碳纳米管的结构、生长机制、合成方法、性质及潜在应用。已发表的数据表明，卷曲碳纳米管的合成是由于碳从催化剂表面不均匀挤出所致。迄今为止，已使用以下催化剂改性技术合成了卷曲碳纳米管：（i）在合成过程中添加含S或P的化合物；（ii）使用二元或三元金属催化剂；（iii）使用微波在单个催化剂颗粒周围产生局部温度梯度；以及（iv）在催化剂制备过程中控制pH值。在大多数情况下，卷曲碳纳米管是作为副产物产生的；卷曲碳纳米管的高产率和/或大规模合成仍然存在问题。目前，由于文献中缺乏具体的表征数据，例如通过热重分析测量的氧化曲线和纯卷曲碳纳米管样品的拉曼光谱，卷曲碳纳米管的定性分析受到阻碍。
