Green chemical functionalization of multiwalled carbon nanotubes with poly(ɛ-caprolactone) in ionic liquids

• Published in: Applied surface science 2010-11, Vol.257 (3), p.1010-1014
• Main Authors: Yang, Yingkui, Qiu, Shengqiang, He, Chengen, He, Wenjie, Yu, Linjuan, Xie, Xiaolin
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Clusters, nanoparticles, and nanocrystalline materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Green functionalization; Infrared and Raman spectra; Infrared and raman spectra and scattering; Ionic liquids; Materials science; Media; Multi wall carbon nanotubes; Nanocomposites; Nanocrystalline materials; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Poly(ɛ-caprolactone); Polymerization; Room temperature ionic liquids; Shells; Structure of solids and liquids; crystallography
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2010.08.009

Multiwalled carbon nanotubes (MWNTs) have been successfully functionalized by free radical addition of 4,4′-azobis(4-cyanopentanol) in aqueous media to generate the terminal-hydroxyl-modified MWNTs (MWNT–OH), followed by surface-initiated in situ ring-opening polymerization of ɛ-caprolactone in 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF 4) to obtain poly(ɛ-caprolactone)-grafted MWNTs (MWNT- g-PCL). Spectroscopic methods in conjunction with electron microscopy clearly revealed that hairy PCL chains were chemically attached to the surface of MWNTs to form core–shell nanostructures with the latter as core and the former as shell. With increasing polymerization time from 2 to 8 h, the amount of the grafted-PCL synthesized in BmimBF 4 varies from 30.6 to 62.7 wt%, which is clearly higher than that (41.5 wt%) obtained in 1,2-dichlorobenzene under comparable conditions (8 h). The proposed methodology here uses water and room temperature ionic liquids (RTILs) as the reaction media and promises a green chemical process for functionalizing nanotubes.