Si Rongmei, Wei Li, Wang Hong, Su Dingdian, Mushrif Samir H, Chen Yuan
School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore), Fax: (+65) 67947553.
Chem Asian J. 2014 Mar;9(3):868-77. doi: 10.1002/asia.201301350. Epub 2013 Dec 20.
Selective polymer wrapping is a promising approach to obtain high-chiral-purity single-walled carbon nanotubes (SWCNTs) needed in technical applications and scientific studies. We showed that among three fluorene-based polymers with different side-chain lengths and backbones, poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,10-anthracene)] (PFH-A) can selectively extract SWCNTs synthesized from the CoSO4 /SiO2 catalyst, which results in enrichment of 78.3 % (9,8) and 12.2 % (9,7) nanotubes among all semiconducting species. These high-chiral-purity SWCNTs may find potential applications in electronics, optoelectronics, and photovoltaics. Furthermore, molecular dynamics simulations suggest that the extraction selectivity of PFH-A relates to the bending and alignment of its alkyl chains and the twisting of its two aromatic backbone units (biphenyl and anthracene) relative to SWCNTs. The strong π-π interaction between polymers and SWCNTs would increase the extraction yield, but it is not beneficial for chiral selectivity. Our findings suggest that the matching between the curvature of SWCNTs and the flexibility of the polymer side chains and the aromatic backbone units is essential in designing novel polymers for selective extraction of (n,m) species.
选择性聚合物包裹是一种很有前景的方法，可用于获取技术应用和科学研究中所需的高纯度手性单壁碳纳米管（SWCNT）。我们发现，在三种具有不同侧链长度和主链的芴基聚合物中，聚[（9,9 - 二己基芴基 - 2,7 - 二基） - 共 - （9,10 - 蒽）]（PFH - A）能够选择性地提取由CoSO4 /SiO2催化剂合成的SWCNT，这导致在所有半导体物种中，（9,8）纳米管的富集率为78.3%，（9,7）纳米管的富集率为12.2%。这些高纯度手性SWCNT可能在电子学、光电子学和光伏领域找到潜在应用。此外，分子动力学模拟表明，PFH - A的提取选择性与其烷基链的弯曲和排列以及其两个芳香主链单元（联苯和蒽）相对于SWCNT的扭曲有关。聚合物与SWCNT之间强烈的π - π相互作用会提高提取产率，但对手性选择性不利。我们的研究结果表明，SWCNT的曲率与聚合物侧链和芳香主链单元的柔韧性之间的匹配对于设计用于选择性提取（n,m）物种的新型聚合物至关重要。
