Covalent Modification of Multiwalled Carbon Nanotubes with Imidazolium-Based Ionic Liquids: Effect of Anions on Solubility

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• 作者：Min Jeong Park ; Jae Kyun Lee ; Bang Sook Lee ; Yong-Won Lee ; Insung S. Choi ; and Sang-gi Lee
• 刊名：Chemistry of Materials
• 出版年：2006
• 出版时间：March 21, 2006
• 年：2006
• 卷：18
• 期：6
• 页码：1546 - 1551
• 全文大小：370K
• 年卷期：v.18,no.6(March 21, 2006)
• ISSN：1520-5002

文摘

Multiwalled carbon nanotubes (MWCNTs) were covalently modified with imidazolium salt-based ionicliquids (ILs). Coupling of acid chloride-functionalized MWCNTs with commercially available (3-aminopropyl)imidazole, followed by the reaction with n-butyl bromide, afforded 1-butylimidazoliumbromide salt-functionalized MWCNTs (f-3a). The bromide anion of f-3a could be exchanged with BF₄^-,PF₆^-, and NTf₂^- (N,N-bis((trifluoromethyl)sulfonyl)amide) by metathesis and afforded functionalizedMWCNTs, f-3b (BF₄^-), f-3c (PF₆^-), and f-3d (NTf₂^-), bearing different counteranions. Raman, IR, NMR,TGA, and XPS analyses clearly confirmed covalent functionalization and imidazolium salt formation aswell as anion exchange of the IL-functionalized MWCNTs. UV-vis data imply that counteranions havean effect on the relative solubility of the IL-functionalized MWCNTs in water: the solubility of f-3 inwater is of the order f-3a (Br^-) > f-3b (BF₄^-) > f-3c (PF₆^-) > f-3d (NTf₂^-), and the water-soluble f-3awas phase-transferred from the aqueous phase to the chloroform phase via simple anion exchange withNTf₂^-. All of the IL-functionalized MWCNTs, including the water-soluble f-3a, exhibited a preferentialsolubility in an ionic liquid, [bmim][NTf₂].