In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl₃·6H₂O) to monomer (3,4-ethylenedioxythiophene (EDOT)). The results from structural analysis showed that the structure of PEDOT was strongly affected by the oxidant/monomer ratio, and the polymerization degree, conjugation length, doping level, and crystallinity of PEDOT decreased with increasing of the oxidant/monomer ratio. The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of ‘coral’ would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1). The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.

A series of polyaniline (PANI) salts were synthesized with the presence of a small amount of water varying from 0 to 1 mL at the beginning of solid-state polymerization. The structure and morphology of the samples were characterized by fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-Vis) absorption spectra, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical performances of the products were investigated by galvanostatic charge-discharge, cyclic voltammetry, cycling stability and electrochemical impedance spectroscopy (EIS). The results showed that the amounts of water can affect the oxidation degree, conjugate level and crystallinity of PANI salts. All PANI salts showed spherical morphology with the diameter of about 60 nm as shown by TEM. The electrochemical tests showed the highest specific capacitance value 593.3 F.g−1 in 1 M H2SO4 for PANI prepared with the addition of 0.5 mL of water at the beginning of solid-state polymerization.

Poly(3,4-ethylenedioxythiophene)/zinc oxide (PEDOT/ZnO) nanocomposites were prepared by a simple solid-state heating method, in which the content of ZnO was varied from 10 to 20 wt%. The structure and morphology of the composites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The photocatalytic activities of the composites were investigated by the degradation of methylene blue (MB) dye in aqueous medium under UV light and natural sunlight irradiation. The FTIR, UV-vis, and XRD results showed that the composites were successfully synthesized, and there was a strong interaction between PEDOT and nano-ZnO. The TEM results suggested that the composites were a mixture of shale-like PEDOT and less aggregated nano-ZnO. The photocatalytic activity results indicated that the incorporation of ZnO nanoparticles in composites can enhance the photocatalytic efficiency of the composites under both UV light and natural sunlight irradiation, and the highest photocatalytic efficiency under UV light (98.7%) and natural sunlight (96.6%) after 5 h occurred in the PEDOT/15wt%ZnO nanocomposite.

In this study, poly(3,4-ethylenedioxythiophene)/thiophene-grafted graphene oxide (PEDOT/Th-GO) composites from covalently linking of Th-GO with PEDOT chain