Blistering failure of elastic coatings with applications to corrosion resistance
Abstract
A variety of polymeric surfaces, such as anti-corrosion coatings and polymer-modified asphalts, are prone to blistering when exposed to moisture and air. As water and oxygen diffuse through the material, dissolved species are produced, which generate osmotic pressure that deforms and debonds the coating. These mechanisms are experimentally well-supported; however, comprehensive macroscopic models capable of predicting the formation osmotic blisters, without extensive data-fitting, is scant. Here, we develop a general mathematical theory of blistering and apply it to the failure of anti-corrosion coatings on carbon steel. The model is able to predict the irreversible, nonlinear blister growth dynamics, which eventually reaches a stable state, ruptures, or undergoes runaway delamination, depending on the mechanical and adhesion properties of the coating. For runaway delamination, the theory predicts a critical delamination length, beyond which unstable corrosion-driven growth occurs. The model is able to fit multiple sets of blister growth data with no fitting parameters. Corrosion experiments are also performed to observe undercoat rusting on carbon steel, which yielded trends comparable with model predictions. The theory is used to define three dimensionless numbers which can be used for engineering design of elastic coatings capable of resisting visible deformation, rupture, and delamination.
Additional Information
© The Royal Society of Chemistry 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Submitted 02 Jul 2021. Accepted 23 Sep 2021. First published 28 Sep 2021. We gratefully acknowledge support from Dow through the University Partnership Initiative and Colin Cwalina from Dow for providing guidance throughout this research project. We thank Dimitrios Fraggedakis and Hongbo Zhao for the insights they shared on this topic. We thank Ernie Latham-Brown and Yu Ren Zhou for the technical advice leading to the schematic in Fig. 6. Author contributions. Surya Effendy and Tingtao Zhou conceptualized the idea of a quantitative macroscopic model for osmotic blistering. Surya Effendy conceptualized the idea for irreversible blister growth driven by difference between adhesion stress and critical adhesion stress (see Section 3.1). Surya Effendy conceptualized the idea of endpoint classification using dimensionless numbers (see Section 4.1). Surya Effendy investigated and curated the data published in ref. 25 and 35, specifically by extracting the data using an image analysis tool and reporting those data for posterity (see Tables S2 and S3 of the ESI†). The data were subsequently used, also by Surya Effendy, to validate components of the model. Henry Eichman investigated the formation of blisters about macroscopic defects, leading to Fig. 10. Michael Petr and Martin Z. Bazant acquired the funding needed to perform this study through the University Partnership Initiative. Michael Petr represented Dow Chemical Company at the time this work was conceived. Martin Z. Bazant heads the Bazant Research Group, in which this work was performed, and provided the resources needed to validate the critical delamination length hypothesis. Surya Effendy created almost all aspects of the model; however, it should be made clear that pieces of the model were already in the literature when the model was conceived. Tingtao Zhou pointed out the relevance of free volume problem, which became eqn (1). Surya Effendy also wrote the software encoding the model leading to the predictions/fits shown in Fig. 8. Tingtao Zhou and Martin Z. Bazant supervised the work and provided advice leading to the publication of the manuscript. Surya Effendy visualized the data, model predictions/fits, and schematics, and wrote the original draft of the manuscript. Tingtao Zhou, Michael Petr, and Martin Z. Bazant contributed in various ways towards reviewing and editing the manuscript. There are no conflicts of interest to declare.Attached Files
Published - d1sm00986a.pdf
Supplemental Material - d1sm00986a1.pdf
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Additional details
- Eprint ID
- 111311
- Resolver ID
- CaltechAUTHORS:20211008-224606664
- Dow Chemical Company
- Created
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2021-10-12Created from EPrint's datestamp field
- Updated
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2021-11-02Created from EPrint's last_modified field