Electropolymerization of PEDOT on CNTs conductive network assembled at water/oil interface

•PEDOT@CNTs composite was prepared via a novel electrochemical method.•CNTs network acts as working electrode for interfacial electropolymerization.•CNTs content in the composite can be controlled by CNTs areal density.•PEDOT@CNTs composite film exhibited improved capacitive performance.•The preparation method can be extended to the synthesis of other composites.

We demonstrate an interfacial electrochemical process for the preparation of composite film of poly(3,4-ethylenedioxythiophene) (PEDOT) and carbon nanotubes (CNTs) at a water/oil (w/o) interface. The 3,4-ethylenedioxythiophene (EDOT) monomer and lithium perchlorate electrolyte were supplied from the oil phase (dichloromethane) and water phase, respectively. Firstly, acid-oxidized carbon nanotubes were assembled at the w/o interface with the assistance of a trace dosage of cationic surfactant, forming a CNTs network. And then the CNTs network acted as a “working electrode” and “reinforcement bars” for the electropolymerization of PEDOT, resulting in the production of PEDOT@CNTs composite film. Higher CNTs areal density (μg/mm2 CNTs) caused a faster radial growth of PEDOT at the CNTs network, namely a faster growth of “apparent area” of the composite film. The current-time curves of the electropolymerization demonstrated that there was an optimal areal density of CNTs network (0.40 μg/mm2) to achieve the largest amount of polymerized PEDOT. These observations suggested that the assembled CNTs network and the formed PEDOT@CNTs composite film not only functioned as an electrical conductor for the electrochemical process, but also affected the mass transfer of the reactants. The prepared PEDOT@CNTs composite film showed heterogeneous structures with a capacitance of 0.148 F/C. The pre-assembled nano-particles network involved liquid-liquid interfacial eletropolymerization may be developed for the preparation of a series of conductive polymer@nanoparticle composite film.

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