A novel method for the synthesis of polyacrylonitrile (PAN)-coated multiwall carbon nanotubes (MWCNTs) via a simple soap-free emulsion polymerization is presented for the first time. The polymerization was initiated with conventional anionic ammonium persulfate (APS) at 65 degrees C. The modification of PAN on MWCNT surfaces was confirmed by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and Raman spectroscopy. It is found that all the surfaces of the MWCNTs were coated by PAN chains, and the PAN coating thickness could be controlled by simply adjusting the polymerization time. The obtained PAN-coated MWCNTs could be well dispersed in water. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2057-2062, 2010