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.

The nanocomposite materials of poly(3,4-ethylenedioxythiophene)/graphene oxide (PEDOT/GO), poly(3,4-ethylenedioxythiophene)/MnO2 (PEDOT/MnO2), and poly(3, 4-ethylenedioxythiophene)/graphene oxide/MnO2 (PEDOT/GO/MnO2) were successfully prepared by facile and template-free solution method. The structure and morphology of nanonanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible absorption spectra (UV–vis), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), respectively. The catalytic activities of nanocomposites were investigated through the degradation processes of methylene blue (MB) solution under dark, UV light, and nature sunlight irradiation, respectively. The results displayed that nanocomposites were successfully synthesized, and PEDOT/GO had higher conjugation length and doped degree than pure PEDOT. However, the introduction of MnO2 could lead to the reduction of conjugation length and doped degree in PEDOT/MnO2 and PEDOT/GO/MnO2 nanocomposites. The field emission scanning electron microscope (FESEM) analysis also showed that both MnO2 and GO had some effect on the morphology of nanocomposites. The catalytic activities of pure PEDOT and nanocomposites were in the order of PEDOT/GO/MnO2 > PEDOT/MnO2 > PEDOT/GO > pure PEDOT. Besides, the catalytic results also showed that the highest degradation efficiency of MB after 7 h occurred in the PEDOT/GO/MnO2 composite in three irradiation.

In this study, poly(3,4-ethylenedioxythiophene)/thiophene-grafted graphene oxide (PEDOT/Th-GO) composites from covalently linking of Th-GO with PEDOT chains were prepared via in situ chemical polymerization with different weight percentage of Th-GO ranging between 40 and 70 % in reaction medium. The resulting composite materials were characterized using a various analytical techniques. The structural analysis showed that the composites displayed a higher degree of conjugation and thermal stability than pure PEDOT, and the weight percentage of Th-GO could affect the doping level, amount of undesired conjugated segments, and porous structure of composites. Electrochemical analysis suggested that the highest specific capacitance of 320 F g−1 at a current density of 1 A g−1 with good cycling stability (capacitance retention of 80 % at 1 A g−1 after 1000 cycles) was achieved for the composite prepared from 50 wt% Th-GO content in reaction medium.

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The paper presents a novel and universally applicable strategy to rapidly screen and identify nontarget flavonoid components from invasive weeds by LC/MS-IT-TOF. The developed strategy was successfully validated to be very useful and powerful for the identification of flavonoid components from three kinds of invasive weeds.