The chirality of single-walled carbon nanotubes affects many of their physical and electronic properties. Current production methods result in nanotubes of mixed chiralities, so facile extraction of specific chiralities of single-walled carbon nanotubes is an important step in their effective utilization. Here we show that the flavin mononucleotide, a common redox cofactor, wraps around single-walled carbon nanotubes in a helical pattern that imparts efficient individualization and chirality selection. The cooperative hydrogen bonding between adjacent flavin moieties results in the formation of a helical ribbon, which organizes around single-walled carbon nanotubes through concentric π-π interactions between the flavin mononucleotide and the underlying graphene wall. The strength of the helical flavin mononucleotide assembly is strongly dependent on nanotube chirality. In the presence of a surfactant, the flavin mononucleotide assembly is disrupted and replaced without precipitation by a surfactant micelle. The significantly higher affinity of the flavin mononucleotide assembly for (8,6)-single-walled carbon nanotubes results in an 85% chirality enrichment from a nanotube sample with broad diameter distribution.
Bibliographical noteFunding Information:
The authors wish to thank Z. Luo, W. Kopcha and C. Badalucco for their help and S. Daniels for valuable discussions. This work has been supported mainly by Air Force Office of Scientific Research (AFOSR) FA9550-06-1-0030, and in part by National Science Foundation (NSF)-Nanoscale Interdisciplinary Research Team (NIRT) DMI-0422724, Army Research Office (ARO)-DAAD-19-02-1-10381, National Institute of Health (NIH)-ES013557 and the U.S. Army Medical Research W81XWH-05-1-0539.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Biomedical Engineering
- Materials Science(all)
- Condensed Matter Physics
- Electrical and Electronic Engineering