A novel and simple thermal imidization method is used to prepare the sulfonated polyimide/Nafion multilayer (NF-SPI-NF) membrane from sulfonated polyimide (SPI) and Nation-containing solution (Na(+) form). The NF-SPI-NF membrane is prepared by immersing a sulfonated poly(amic acid) (SPAA) membrane into the Nation-containing solution followed by thermal imidization via solvent evaporation. This Nation is firmly adhered to either side of the SPI membrane via thermal imidization. The prepared membranes are characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and proton conductivity. The membranes are immersed in Fenton's reagent at room temperature to test their oxidative stability and the durability of a single proton exchange membrane fuel cell (PEMFC) system. Analytical results show a marked improvement in NF-SPI-NF membrane stability by adding Nation layer comparing with that of native SPI membrane. The performance of PEMFC with the NF-SPI-NF membrane is similar to that of PEMFC with the commercially available Nation 212 at 70 degrees C. (C) 2011 Published by Elsevier B.V.