NOVELTY - Forming a metal-polymer composite involves either contacting a thermally-cured dense polyaniline (PANI) substrate with an acid dopant to form a doped substrate; and then with a solution comprising a metal ion; or contacting thermally-cured dense polyaniline substrate with a solution comprising a metal ion and an acid dopant to form metal nanostructure deposits on the doped substrate, and the deposits have a morphology which is dependent upon the acid dopant.    USE - For forming a metal-polymer composite used for performing surface-enhanced Raman spectral analysis of an analyte (Claimed); in surface processing, catalysis (e.g., in fuel cells or other chemical reactions), and as modified surface electrodes, for anticorrosion and for biosensors.    ADVANTAGE - The metal-PANI composites provide good catalytic activity to various organic reactions especially toward hydrogenation reactions. As the metal., e.g., metal nanoparticles, are stably fixed to the PANI membrane, it can be easily recycled and reused whereas typical commercially available metal catalysts, e.g., Pd on C, can only be used once. The metal-PANI composites comprising platinum or palladium can be used in the selective hydrogenation of alkenes and alkynes. Using the present method, the formation of metals on reductive PANI surfaces can be controlled by tailoring the surface chemistry and redox potential. A wide range of metal nanostructure morphologies can be achieved by selection of dopant. The sizes of the deposited metal structures can also be varied from a few nanometers to several microns.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method of performing surface-enhanced Raman spectral analysis of an analyte involving: a) providing a thermally-cured dense polyaniline substrate, where surface of the substrate comprises metal nanostructure deposits and an acid dopant; b) bringing an analyte into contact with the metal-PANI composite; c) illuminating the metal-PANI composite with radiation of at least one wavelength for causing elemental-state particles to produce a plasmon field and for causing the plasmon field to interact with molecules of the analyte, in such a manner, so as to produce Raman photons; and, d) collecting scatted radiation emitted from the metal-PANI composite for spectral analysis.