Preparation and characterization of poly(N-isopropylacrylamide) (PNIPAM) polymer brushes on the surfaces of reduced graphene oxide (RGO) sheets based on click chemistry and reversible addition-fragmentation chain transfer (RAFT) polymerization was reported. RGO sheets prepared by thermal reduction were modified by diazonium salt of propargyl p-aminobenzoate, and alkyne-functionalized RGO sheets were obtained. RAFT chain transfer agent (CTA) was grafted to the surfaces of RGO sheets by click reaction. PNIPAM on RGO sheets was prepared by RAFT polymerization. Fourier transform-infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM) results all demonstrated that RAFT CTA and PNIPAM were successfully produced on the surfaces of RGO sheets. Nanosized PNIPAM domains on RGO sheets were observed on TEM. Micro-DSC result indicated that in aqueous solution PNIPAM on RGO sheets presented a lower critical solution temperature at 33.2 degrees C. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 329-337, 2012