Enhanced electrical conductivity of Ag-mercaptosuccinic acid-redoped polyaniline nanoparticles during thermal cycling above 200 deg C

Ag-doped polyaniline (PANI) nanoparticles are prepared via doping-dedoping-redoping with the thiol group in mercaptosuccinic acid (MSA) providing the linkage between PANI molecules and Ag atoms. Ag-MSA-doped PANI maintains the electrical conductivity well above the room-temperature value of 3.0 S/cm up to 220 deg C, reaching its maximum (9.0 S/cm) at 180 deg C. In addition, Ag-MSA-doped PANI nanoparticles show remarkable stability against repeated thermal aging at 120 deg C. The room-temperature conductivity, in fact, increases by a factor of 3 after 3 cycles of thermal aging. The enhanced stability against repeated thermal aging is attributed to the formation of uniformly distributed Ag nanoparticles within the PANI particles upon heating.