Electrochemical and Spectroscopic (FTIR) Evidence of Conducting Polymer-Cu Ions Interaction

In this work, we provide electrochemical and spectroscopic evidence of the conducting polymer-heavy metal ion interaction by comparing the electrochemical and spectroscopic behavior (FTIR) of two different conducting polymer-modified electrodes based on 3,4-alkoxythiophenes: 3,4-ethylenedioxythiophene (EDOT) and ortho-xylen-3,4-dioxythiophene (XDOT) during the potentiodynamic stripping of copper. By analyzing the electrochemical and spectroscopic results, it is possible to propose two different copper dissolution processes during the electrochemical stripping process, which depend on the conducting polymer used. With PEDOT matrix, stripping occurs in a two-step pathway, observed as two anodic peaks, involving the formation of the Cu+-PEDOT complex and the subsequent oxidation step of the Cu+ complex to release Cu2+ ions. On the other side, the experiments carried out let us propose the formation of a poorly stable Cu2+-PXDOT complex or a superficial mechanism for the Cu2+ release, characterized by a single stripping signal for this process. Thus, the incorporation of Cu ions into the matrix and the stripping release are intimately related to the chemical structure of the polymer used.

Automated summary

In this study, we provide evidence of the interaction between conducting polymer and heavy metal ions through electrochemical and spectroscopic analysis. By comparing the behavior of two different conducting polymer-modified electrodes (PEDOT and PXDOT) during the potentiodynamic stripping of copper, we propose two different copper dissolution processes depending on the conducting polymer used. With PEDOT, stripping occurs in a two-step pathway involving the formation of Cu+-PEDOT complex and subsequent oxidation of the complex to release Cu2+ ions. On the other hand, the experiments suggest a poorly stable Cu2+-PXDOT complex or a superficial mechanism for Cu2+ release in the PXDOT system.