Medium Effects on the Nucleation and Growth Mechanisms during the Redox Switching Dynamics of Conducting Polymers: Case of Poly(3,4-ethylenedioxythiophene)

Abstract

The redox switching dynamics of poly(3,4-ethylenedioxythiophene) (PEDOT) in an acetonitrile solution and a room temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmiTFSI), are investigated by means of potential step experiments. Redox switching can be viewed as a phase transition in which the nucleation and growth processes occur. We have developed a phenomenological model allowing the determination of the kinetic parameters. Two limiting cases are shown as follows: (i) a progressive and (ii) an instantaneous nucleation. In all cases, the growth process is described in terms of a self-exchange electron transfer reaction. We show that the mechanisms depend upon the medium. In acetonitrile, progressive nucleation and growth occur during oxidation (p-doping), whereas nucleation is instantaneous in the reduction of the PEDOT film. On the other hand, instantaneous nucleation and growth mechanisms are observed for both oxidation and reduction in EmiTFSI. The difference in the mechanisms results from the ionic exchange process associated with electron transfer and the initial structure of the film (open or compact). The influence of the applied potential on the dynamics is analyzed for both media.

Structural Electrochemistry from Freestanding Polypyrrole Films: Full Hydrogen Inhibition from Aqueous Solutions

“…The oxidation under conformational relaxation kinetic control of compacted initial states is initiated, forming nuclei, visualized from electrochromic fi lms, [ 58,70 ] predicted by the ESCR model, and here corroborated by the nucleation loops on different voltammetric responses. After coalescence of the relaxed nuclei, the uniform oxidation/swelling of the fi lm goes on under diffusion kinetic control of the counterion inside the fi lm.…”

Influence of Chemical and Structural Properties of Functionalized Polythiophene‐Based Layers on Electrochemical Sensing of Atrazine

“…After this electrosynthesis step, the obtained MICP, NICP, and PEDOT films exhibit voltammograms as shown in Figure 1 These features agree with the generally accepted redox behavior of conducting polymers. [33][34][35] The voltammograms of NICP and MICP copolymers are very different from that of PEDOT homopolymer (Figure 1, curves b and c respectively). This result confirms the presence of AAT, in addition to EDOT, in the polymer matrix of electrosynthesized MICP and NICP.…”

IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf2N ionic liquid

“…Besides the synthesis technique, there are two important factors that can influence the polymer properties: the surface structure of the electrode and the solvent used [ 2 , 5 ]. It has been reported that the nucleation and growth kinetics, and the electrochemical properties, as the ionic resistance or the electrocatalytic activity, of PEDOT are affected by the surface energy state of the electrode [ 6 ].…”