Chemical synthesis of high density and long polypyrrole nanowire arrays using alumina membrane and their hydrogen sensing properties

Polypyrrole nanowire arrays were synthesized through chemical polymerization inside the nanochannels of alumina membrane. By optimizing the polymerization time and applying appropriate oxidant:monomer molar ratio with proper concentrations, the pores filling and also the continuity of the obtained polypyrrole inside the nanochannels improved and therefore after dissolution of the host membrane, high density and long nanowire arrays appeared. The obtained nanostructures were characterized by SEM, FTIR and BET techniques. The synthesized nanostructures had high surface areas of 75.66–172.90 m²/g. Since nanowires are attractive for gas sensing applications owing to their high surface areas, their hydrogen gas sensing was investigated at room temperature. The results show that the electrical resistance of the polypyrrole nanostructure arrays reduced upon exposure to hydrogen gas.