Doping of the Processable Conducting Poly(m-Aminophenol) with Inorganic Acids

Abstract

Poly(m-aminophenol) (PmAP) was synthesized from m-aminophenol (mAP) in aqueous sodium hydroxide (NaOH) using ammonium persulfate (APS) as an oxidative initiator. Free standing PmAP films were cast from dimethyl sulfoxide (DMSO) solution of the polymer. Then the film was doped with various inorganic acids using a solution doping technique. Various inorganic acid doped PmAP films were characterized by ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), and energy dispersive X-ray (EDS) spectroscopies, X-ray diffraction (XRD) analysis and elemental (C, H, N, S, O) analysis. All the results were explained on a comparative basis and the doping scheme was proposed. The DC-conductivity of the inorganic acid doped films was measured using a standard four-probe method. From the DC-conductivity measurements it was found that sulfuric acid had a better doping effect in terms of conductivity than that of the other inorganic acids used, perchloric acid and phosphoric acid. An explanation of the reason for the better doping effect of sulfuric acid than that of the other inorganic acids is given.

Keywords:

• conducting polymers
• doping effects
• energy dispersive X-ray diffraction
• inorganic acid doping
• poly(m-aminophenol)