Electrochemo-dynamical characterization of polypyrrole actuators coated on gold electrodes

Abstract

Polypyrrole coated gold wires were subjected to consecutive square current waves in LiClO4 aqueous solutions using the same constant anodic and cathodic charge. Parallel in situ diameter variations were followed using a laser scan micrometer. The procedure was repeated by changing one experimental variable every time: applied current, electrolyte concentration or working temperature to perform electrochemodynamical characterization of the system. On average, the diameter follows a linear variation of the consumed charge, as expected for any faradaic system, although a high dispersion was attained in the data. Such deviations were attributed to the presence of irreversible hydrogen evolution at the gold/polypyrrole interface at cathodic potentials more than 0.0 V vs. Ag/AgCl, detected and quantified from separated coulovoltammetric responses. Despite this parallel hydrogen evolution the consumed energy during reactions is a robust sensor of the working conditions. In conclusion a gold support, the metal most used for technological applications of conducting polymers, should be avoided when a device is driven by current flow in the presence of aqueous solutions, water contamination or moisture: a fraction of the charge will be consumed by hydrogen generation with possible degradation of the device.

A Potentiostatic/Galvanostatic Study and Theoretical Description of Polypyrrole Film Electrodes: A Model of the Intracellular Matrix of Ectothermic Muscle Cells

“…The analysis of the polypyrrole films after oxidation or reduction in NaCl aqueous solutions indicates that the electrochemical reactions drive the exchange of anions with the electrolyte ,. Thus the reversible electrochemical process of p‐doping/p‐de‐doping (oxidation/reduction) of pPy films in this electrolyte can be written as [Eq.…”

Electrochemical Synthesis and Characterization of Flavin Mononucleotide‐Exfoliated Pristine Graphene/Polypyrrole Composites

“…Figure indicates that the best potential range for the electrogeneration of the FMN−G‐PPy composites goes from 0.55 V, where the monomer oxidation‐polymerization begins, until 1.20 V, where the oxygen evolution from the aqueous dispersion starts. In this way, the oxygen evolution and the concomitant local variation of the pH in parallel to the electropolymerization process are avoided, thus circumventing simultaneous polymeric over‐oxidation and degradation processes …”

Enhancing the Conductivity of the Poly(3,4‐ethylenedioxythiophene)‐Poly(styrenesulfonate) Coating and Its Effect on the Performance of Yarn Actuators

“…There are several factors influencing CP actuation. A wider voltage range applied to the polymer contributes to larger actuation strain, although too high values could promote the degradation of the CP by overoxidation or the presence of parallel reactions that may affect the oxidation/reduction of the CP originating the movement . Another main factor is the ion transport.…”