The effect of superhydrophobic wetting state on corrosion protection - The AKD example

Research output: Contribution to journalArticle

Abstract

Corrosion is of considerable concern whenever metal is used as construction material. In this study we address whether superhydrophobic coatings could be used as part of an environmentally friendly corrosion-protective system, and specific focus is put on how the wetting regime of a superhydrophobic coating affects corrosion inhibition. Superhydrophobic alkyl ketene dimer (AKD) wax coatings were produced, using different methods resulting in hierarchical structures, where the coatings exhibit the same surface chemistry but different wetting regimes. Contact angle measurements, ESEM, confocal Raman microscopy, open circuit potential and electrochemical impedance spectroscopy were used to evaluate the surfaces. Remarkably high impedance values of 10(10) Omega cm(2) (at 10(-2) Hz) were reached for the sample showing superhydrophobic lotus-like wetting. Simultaneous open circuit potential measurements suggest that the circuit is broken, most likely due to the formation of a thin air layer at the coating-water interface that inhibits ion transport from the electrolyte to the metal substrate. The remaining samples, showing superhydrophobic wetting in the rose state and hydrophobic Wenzel-like wetting, showed less promising corrosion-protective properties. Due to the absence of air films on these surfaces the coatings were penetrated by the electrolyte, which allowed the corrosion reaction to proceed. (C) 2013 Elsevier Inc. All rights reserved.

Details

Authors
  • Lina Ejenstam
  • Louise Ovaskainen
  • Irene Rodriguez Meizoso
  • Lars Wagberg
  • Jinshan Pan
  • Agne Swerin
  • Per M. Claesson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Sciences

Keywords

  • Superhydrophobic coating, Wetting state, Corrosion protection, Alkyl, ketene timer (AKD)
Original languageEnglish
Pages (from-to)56-64
JournalJournal of Colloid and Interface Science
Volume412
Publication statusPublished - 2013
Publication categoryResearch
Peer-reviewedYes