High yield and facile microwave-assisted synthesis of conductive H2SO4 doped polyanilines

• Nanoporous microwave synthesized doped polyanilines as chemical sensor material.
• Morphology and physical properties of polyanilines depend on acid concentration.
• Spin concentration is determined by the nature of the polyaniline synthesis.

The microwave-assisted synthesis of polyaniline (PANI) was performed using ammonium persulphate (APS) as oxidizing agent in 0.5 M–2.5 M concentration range of aqueous sulphuric acid (H2SO4) at 93 W applied microwave power of 10 min duration. The microwave (MW) synthesized PANIs had 3 times higher yield in comparison to PANI samples prepared using a classical method, CS (0 W MW power) at the same temperature for 10 min synthesis duration period. Fourier Transform Infrared (FTIR) and UV–Vis spectroscopies confirmed the formation of PANI structure in all products. The influence of H2SO4 acid dopant on the spin concentration of MW and CS H2SO4 doped PANI samples were examined by EPR spectroscopy, while the morphological characteristics were investigated by using scanning electron microscopy (SEM). XRD results showed amorphous phases in both MW and CS H2SO4 doped PANI samples. Conductivity measurements revealed ∼1.5 times higher conductivity values for MW H2SO4 doped PANI samples in comparison with PANI samples prepared by the CS method under same condition. The influence of sulfate anion in comparison to chloride anion as a dopant on morphological, dopant levels and conductivity properties of MW PANI samples were also investigated.

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