Exfoliated polypyrrole graft copolymer/clay nanocomposites were prepared by in situ polymerization of pyrrole onto pre-exfoliated water-soluble poly(styrenesulfonic acid-co-pyrrolylmethyl styrene) (P(SSA-co-PMS))/clay nanocomposite or by simple blending of poly(styrenesulfonic acid-g-pyrrole) (PSSA-g-PPY) with clay. As the clay content in PSSA-g-PPY/clay nanocomposite increases, the conductivity of PSSA-g-PPY/clay nanocomposite decreases. Thermal de-doping temperature shifts to higher temperature as the clay content in PSSA-g-PPY/clay nanocomposite increases. (c) 2005 Elsevier Ltd. All rights reserved.