One-pot methods for preparing polyaniline/Ag nanocomposites via oxidative polymerization of aniline

Abstract

Ag-loaded polyaniline nanocomposites in the form of their fully oxidized pernigraniline bases (PB’s) are synthesized by one-pot chemical oxidation of aniline monomer using silver ion oxidant via two parallel methods. These two methods are compared with each other with respect to the content and size of the particle loaded. In method 1, leading to PB/Ag-1, ammonium peroxydisulfate (APS) and silver ion oxidants are used for two consecutive steps involving oxidative polymerization of aniline and oxidation of the emeraldine salt intermediate, respectively. In method 2, leading to PB/Ag-2, silver ions play the role of the oxidant in the polymerization step and inversely, APS oxidizes the intermediate salt obtained to the final nanocomposite. A significant enhancement in the content of the particle loaded could be resulted in method 2 (68.1 vs. 18.5 % by weight). Moreover, in method 2, the average size of the silver nanoparticles loaded into the PB matrix is found to be lesser than the method 1 (30 vs. 52 nm). TGA/DTG thermogram of PB/Ag-2 shows that the organic part of the nanocomposite (~30 wt%) undergoes a gradual thermo-degradation through a four-step pattern, mainly occurred at about 350 °C.