Template-free solid state synthesis of ultra-long hairy polyaniline nanowire supercapacitor

•Ultra-long hairy wire-like nanostructure for citric acid doped PANI was revealed.•Nanowire formation mechanism has been proposed.•Very simple method of solid state polymerization was followed for the synthesis.•No post-synthesis treatment is required for the synthesis of PANI nanowire.•Superior supercapacitative behavior and thermal stability for PANI nanowire.

Present investigation deals with the formation of ultra-long hairy polyaniline (PANI) nanowire synthesized via mechanochemical (solid state) polymerization method using ammonium peroxydisulphate (APS) as an oxidant and citric acid as a dopant. Solid state synthesis method is a simple mechanochemical route for synthesis of PANI. Granular nanostructure is observed for undoped PANI, whereas doping with citric acid facilitates the formation of nanowire structure. This is the first ever report of nanowire structure of PANI using mechanochemical route. Undoped PANI granules agglomerate directionally or arbitrarily to form rods or clusters. PANI nanowires agglomerate to form irregular structures. FTIR spectra prove successful formation of PANI. Smaller PANI nanoparticles are joined end-to-end by dopant to form ultra-long hairy nanowire. Citric acid doped PANI nanowire exhibits less thermal degradation and superior supercapacitative performance compared to undoped PANI.

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