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Facile Functionalization of Multilayer Fullerenes (Carbon Nano‐Onions) by Nitrene Chemistry and “Grafting from” Strategy
Author(s) -
Zhou Li,
Gao Chao,
Zhu Dandan,
Xu Weijian,
Chen Fanqing Frank,
Palkar Amit,
Echegoyen Luis,
Kong Eric SiuWai
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801642
Subject(s) - atom transfer radical polymerization , surface modification , polymer chemistry , thermogravimetric analysis , polystyrene , polymerization , polymer , chemistry , fullerene chemistry , materials science , chemical engineering , fullerene , organic chemistry , engineering
Facile functionalization of multilayer fullerenes (carbon nano‐onions, CNOs) was carried out by [2+1] cycloaddition of nitrenes. The products were further derivatized by using the “grafting from” strategy of in situ ring‐opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Using one‐step nitrene chemistry with high‐energy reagents, such as azidoethanol and azidoethyl 2‐bromo‐2‐methyl propanoate, in N ‐methyl‐2‐pyrrolidone at 160°C for 16 h, hydroxyl and bromide functionalities were introduced onto the surfaces of CNOs. These hydroxyl CNOs (CNO‐OH) and bromic CNOs (CNO‐Br) were extensively characterized by various techniques such as thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), Raman spectroscopy and X‐ray photo electron spectroscopy (XPS). TGA measurements indicated that the surface hydroxyl and bromide group density reached 1.49 and 0.49 mmol g −1 , respectively. The as‐functionalized CNOs showed much better solubility in solvents than pristine CNOs. The CNO‐OH were also observed to fluoresce at λ =453 nm in water. The CNO‐OH and CNO‐Br can be conveniently utilized as macroinitiators to conduct surface‐initiated in‐situ polymerizations. Poly( ε ‐caprolactone) (PCL, 45wt %) and polystyrene (PS, 60 wt%) were then grafted from surfaces of CNOs through the ROP of ε ‐caprolactone with the macroinitiator CNO‐OH and the ATRP of styrene with the macroinitiator CNO‐Br, respectively. The structures and morphology of the resulting products were characterized by 1 H NMR, scanning electron microscopy (SEM), TEM, and atomic force microscopy (AFM). The polymer functionalized CNOs have good solubility/dispersibility in common organic solvents. The facile and scalable functionalization approaches can pave the way for the comprehensive investigation of chemistry of CNOs and fabrication of novel CNO‐based nanomaterials and nanodevices.