Nanocomposites of polyaniline (PANI) and single-wall carbon nanotubes (SWNTs) were prepared and characterized via resonance Raman and electronic absorption spectroscopy (ultraviolet-visible/near-infrared). The chemical synthesis of PANI was performed in the presence of SWNTs in concentrations ranging from 10 to 50 wt % (SWNT/PANI). The obtained materials were hydrophilic. homogeneous composite compounds. The chemical interaction between PANI (in the conducting emeraldine Salt form and in the insulating emeraldine base form) and metallic and Semiconductinq nanotubes was investigated. The emeraldine salt, form of the polymer was significantly stabilized in the composite in comparison with plain PANI. A selective electronic interaction process between PANI and metallic SWNTs was found. (C) 2005 Wiley Periodicals, Inc.