Mercaptoethanol-Substituted Polyaniline/Silver Nanocomposites Prepared by Concurrent Reduction and Substitution Chemistry

Abstract

Mercaptoethanol (ME)-modified PANI/Ag composite particles were prepared by two-step process comprising the reduction of the PANI chains and the simultaneous reduction-oxidation reaction of AgNO3 and PANI chains. In the first stage, ME-modified PANI particles were prepared by a concurrent reduction and substitution (CRS) route. ME as nucleophile reduced a PANI backbone from the emeraldine state (half-oxidized state) to the leucoemeraldine state (fully-reduced state) and simultaneously derivatize the PANI backbone. In the second stage, AgNO3 solution was added to ME-modified PANI dispersion and the Ag+ ions were immediately reduced with the simultaneous oxidation of PANI chains. The molar ratio of AgNO3 to aniline unit in the PANI chains was varied from 1:16 to 1:1. It was verified that the chains of the ME-modified PANI were more reduced than those of the PANI in the emeraldine base form and the Ag content in the composite increased with the [AgNO3] : [Aniline] molar ratio by FT-IR, EDX, XPS and XRD. The thermal stability of the PANI/Ag composites was investigated by TGA.