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Covalent functionalization of alkyne-decorated multiwalled carbon nanotubes (MWNTs) with a well-defined, azide-derivatized, thermoresponsive diblock copolymer, poly(N,N-dimethylacrylamide)-poly(N-isopropylacrylamide) (PDMA-PNI-PAM) was accomplished by the Cu(I)-catalyzed [3 þ 2] Huisgen cycloaddition. It was found that this reaction could simultaneously increase the molecular size and bonding density of grafted polymers when PDMA-PNIPAM micelles were employed in the coupling system. On the other hand, attachment of molecularly dissolved unimers of high-molecular weight onto the nanotube resulted in low-graft density. The block copolymer bearing azide groups at the PDMA end was prepared by reversible addition-fragmentation transfer polymerization, which formed micelles with a diameter of $40 nm at temperatures above its critical micelle temperature. Scanning electron microscopy was utilized to demonstrate that the coupling reaction was successfully carried out between copolymer micelles and alkyne-bearing MWNTs. FTIR spectroscopy was utilized to follow the introduction and consumption of alkyne groups on the MWNTs. Thermogravimetric analysis indicated that the functionalized MWNTs consisted of about 45% polymer. Transmission electron microscopy was utilized to image polymer-functionalized MWNTs, showing relatively uniform polymer coatings present on the surface of nanotubes. V

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