UV-curing synthesis of sulfonated polyaniline-silver nanocomposites by an in situ reduction method

Sulfonated polyaniline-silver (SPAni-Ag) hybrid nanocomposites have been synthesized by the in situ reduction using a UV-curing polymerization method without using any reducing or binding agent. An aqueous solution of aniline and orthoanilinic acid (OA) comonomers, a free-radical oxidant and silver metal salts were irradiated by UV rays. Reduction of the silver salt in aqueous aniline and OA leads to the formation of silver particles which in turn catalyze the oxidation of comonomers to sulfonated polyaniline (SPAni). The resultant SPAni-Ag nanocomposites were characterized by using different spectroscopy analyses like UV-visible (UV-Vis), X-ray diffraction (XRD) and infrared spectroscopy. The absorption bands were revealed to be optically active and the peaks blue-shifted due to the presence of metallic silver within the SPAni matrix. The XRD patterns displayed both the broad amorphous polymeric and sharp metallic peaks. Scanning electron microscopy and transmission electron microscopy of the nanocomposites showed a uniform size distribution with spherical and granular morphology. Thermogravimetric analysis revealed that the nanocomposites had a better thermal stability than the bulk SPAni.