Effects of preparation method on thermoelectric properties of poly(aniline-co-3,4-ethylenedioxythiophene)/SWCNT composites

Composites of conducting polymer and single-walled carbon nanotubes (SWCNTs) are attracting great attentions in harvesting low-grade waste heat. Prefabricated SWCNTs film used as the working electrode was placed at the liquid interface between the inorganic phase (dilute sulfuric acid solution) and the organic phase consisting of dichloromethane (DCM), aniline (ANI), and 3,4-ethylenedioxythiophene (EDOT), together with a platinum wire (the counter electrode) and a silver chloride (AgCl/Ag) electrode (the reference electrode), to perform electrochemical polymerization of ANI and EDOT at the liquid interface. Thermoelectric (TE) composites of poly(ANI-co-EDOT) and SWCNTs were produced. Compared with composites from ultrasonic mixing and coating methods, the 10 wt% SWCNTs-composites in situ formed in electrochemical polymerization have the highest power factor (PF) of 41.56 ± 3.58 μW m⁻¹ K⁻², higher than the PF values of the composites formed by other two methods. The work indicates that the TE properties of ANI-EDOT copolymer/SWCNT (poly[ANI-co-EDOT]/SWCNT) composites prepared by electrochemical polymerization were better than those of the composites obtained by physical mixing the electrochemically synthesized poly(ANI-co-EDOT) with SWCNTs. Moreover, SWCNTs treated with sodium dodecylbenzene sulfonate (SDBS) could further improve the TE properties of the composites.