非共价法分离光学活性单壁碳纳米管

Non-Covalent Separation of Optically Active Single-Walled Carbon Nanotubes

单壁碳纳米管(SWNTs)由于具有独特的物理、化学性质,激起人们极大的研究兴趣。目前生产的SWNTs通常包含等量左旋和右旋对映异构体,无光学活性,极大地限制碳纳米管在光学和光电子领域的研究和应用。已报道的非共价法分离光学活性碳纳米管的方法主要有离子交换色谱法、nanotweezers选择法、密度梯度超高速离心法、共轭聚合物缠绕法和小分子吸附法。本文较为详尽地综述了非共价法分离光学活性碳纳米管的研究进展,对各种分离方法的机理进行阐述,并在此基础上分析这些方法和分离效果的关系,指导设计和合成新型的分离试剂。最后,本文还针对上述研究中存在的问题,提出了旋光性SWNTs分离技术的研究方向。

Single-walled carbon nanotubes （SWNTs） have been attracting extensive interest because of their novel and unique chemical and physical properties. However, the present technologies for SWNTs synthesis always produce samples with both enantiomers in equal amounts. Since the optically active properties of SWNTs are closely correlated to their helical structures, structural control of SWNTs is very important for their potential applications in photonics and photoelectronics. A wide variety of methods have been devised so far for the non- covalent separation of SWNTs according to their left- and right-handed structure. In this paper, they are classified into the following five sections according to the separation methods： ion exchange chromatography, nanotweezers selective extraction, density-gradient ultracentrifugation （DGU）, conjugated polymers wrapping and small molecules adsorption. We reviewed the recent advances in this research field, including the separation mechanisms. The relationship between these methods and the results of the optical and （n,m） enhancements of the extracted SWNTs is analyzed, and it may be useful for designing the novel host molecules to obtain single structure SWNTs in view of practical applications. At last, the existing problems and the direction of development of the regarding studies are pointed out.