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Capillary electrophoresis of covalently functionalized single‐chirality carbon nanotubes
Author(s) -
He Pingli,
Meany Brendan,
Wang Chunyan,
Piao Yanmei,
Kwon Hyejin,
Deng Shunliu,
Wang YuHuang
Publication year - 2017
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201600570
Subject(s) - chirality (physics) , carbon nanotube , covalent bond , surface modification , tetrafluoroborate , nanomaterials , materials science , chemical engineering , chemistry , ionic bonding , surface charge , raman spectroscopy , analytical chemistry (journal) , ionic liquid , nanotechnology , organic chemistry , catalysis , ion , physics , chiral symmetry breaking , optics , quantum mechanics , nambu–jona lasinio model , engineering , quark
We demonstrate the separation of chirality‐enriched single‐walled carbon nanotubes (SWCNTs) by degree of surface functionalization using high‐performance CE. Controlled amounts of negatively charged and positively charged functional groups were attached to the sidewall of chirality‐enriched SWCNTs through covalent functionalization using 4‐carboxybenzenediazonium tetrafluoroborate or 4‐diazo‐ N,N ‐diethylaniline tetrafluoroborate, respectively. Surfactant‐ and pH‐dependent studies confirmed that under conditions that minimized ionic screening effects, separation of these functionalized SWCNTs was strongly dependent on the surface charge density introduced through covalent surface chemistry. For both heterogeneous mixtures and single‐chirality‐enriched samples, covalently functionalized SWCNTs showed substantially increased peak width in electropherogram spectra compared to nonfunctionalized SWCNTs, which can be attributed to a distribution of surface charges along the functionalized nanotubes. Successful separation of functionalized single‐chirality SWCNTs by functional density was confirmed with UV‐Vis‐NIR absorption and Raman scattering spectroscopies of fraction collected samples. These results suggest a high degree of structural heterogeneity in covalently functionalized SWCNTs, even for chirality‐enriched samples, and show the feasibility of applying CE for high‐performance separation of nanomaterials based on differences in surface functional density.