Synthesis and Characterization of PEDOT, an Intrinsically Conductive Polymer

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a highly valuable polymer material for modem electronics due to its impressive electrical conductivity (up to 1000 S.cm(-1)). Combined with poly(styrenesulfonate) (PSS), PEDOT can be processed into thin film for a multitude of applications [1]. However, the introduction of PEDOT in melt-state processes of the plastic industry is still challenging because PEDOT is infusible and only commercially available as highly diluted aqueous solutions. Nevertheless, previous study showed that extrusion processing ofPEDOT: PSS solutions with PEO as a melting carrier is possiblebut sophisticated pre/post-treatments are mandatory to maintain high level of electrical conductivity up to 5 S.cm(-1) [2]. In this context, the goal of this study is to synthesize electrically conductive polymeric particles of PEDOT. An oxidative chemical polymerization of EDOT was carried out using two different oxidants: Fez(SO4)(3) and FeCl3. Resulting polymeric particles were studied thanks to SEM observations and resistivity measurements. The influence of parameters such as the ratio (monomer/oxidant), the polymerization time or the use of surfactants on the conductivity of PEDOT particles was studied. Interestingly, as-prepared PEDOT particles display conductivities between 0.1 and 10 S.cm(-1) without any post treatment. This result is nearly 1000 times higher than previously reported by Jiang et al. [1]. A first explanation can be the presence of the oxidant/surfactant combined with PEDOT particles and acting as a dopant. Besides, comparison between the samples allows us to highlight the impact of the monomer-oxidant ratio on the electrical conductivity of the pellets. To better understand these results, correlations between (i) the polymerization process, (ii) the particles morphology and (iii) final electrical properties are currently being investigated.