An in situ spectro-electrochemical monitoring of aqueous effects on polymer/metal oxide interfaces

Sven Pletincx*, Johannes M.C. Mol, Herman Terryn, Annick Hubin, Tom Hauffman

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)
    17 Downloads (Pure)

    Abstract

    A spectro-electrochemical setup of Fourier transform infrared spectroscopy (FTIR) in the Kretschmann geometry and odd random phase multisine electrochemical impedance spectroscopy (ORP EIS) is applied to in situ monitor the effect of an aqueous electrolyte on the polymer/metal oxide interface. The interfacial interactions of an ultrathin polyacrylic acid (PAA) film on an aluminum oxide surface are identified as carboxylate ionic bonds and changes induced by the effect of water diffusion at the interface are monitored in situ. Initially after electrolyte exposure, an increase in ionic bonding is observed. However, eventually the interfacial interactions are replaced by water molecules, leading to macroscopic delamination. By comparing a variation of oxide types, the stability of the interfacial bonds is linked to the amount of free hydroxyl groups on the aluminum oxide surface. An electric equivalent circuit is proposed to model the ORP EIS response of the PAA/aluminum oxide system and the fitted resistance values could be interpreted in a physically meaningful way. Finally, a poly(methyl methacrylate) (PMMA) deposition on aluminum oxide is investigated to explore the effect of a variation in functional groups present at the polymer/metal oxide interface. It is shown that PMMA forms a more stable interface than PAA on native aluminum oxide. This work demonstrates that IR spectroscopy in the Kretschmann geometry and ORP EIS are suited techniques to in situ probe interfacial bonds at polymer/metal oxide systems exposed to aqueous conditions. Moreover, a variation of the surface properties of the metal oxide as well as the functional groups of the polymer alter the stability of their mutual interface when exposed to aqueous conditions.

    Original languageEnglish
    Article number113311
    Number of pages16
    JournalJournal of Electroanalytical Chemistry
    Volume848
    DOIs
    Publication statusPublished - 2019

    Bibliographical note

    Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care
    Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

    Keywords

    • ATR-FTIR Kretschmann
    • Buried interface
    • In situ
    • Odd random phase multisine electrochemical impedance spectroscopy
    • Polymer/metal oxide

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