Research Progress on Trigger Mechanism and Preparation Strategy of Coatings of Defect Self-disclosure
Organic coating is widely applied to hinder the corrosion of large-scale engineering facili-ties,such as offshore platforms,oceangoing freighters,oil and gas pipelines and rail equipment etc.How-ever,coatings are often severely deteriorated in harsh service environments,thus leading to corrosion of metallic substrates,which may not only threaten the service safety of the engineering facilities but also cause significant economic losses.Moreover,the coating degradation is an unavoidable and spontane-ous process,and it should be mentioned especially that some hidden coating defects are hard to be de-tected.Therefore,it has become a research hotspot to develop coatings with function of defect self-disclo-sure for early detection and maintenance of defects by applying color reaction or fluorescence probe tech-nology.In this review,we summarize the latest advances in coatings of defect self-disclosure,as well as the relevant trigger mechanisms and preparation strategies.First,the coatings of defect self-disclosure can be classified as corrosion-triggered type and mechanical-triggered type based on their mechanisms.Then the corrosion-triggered coatings may be subdivided into pH response and metal ion response ac-cording to the fluorescence change or color reaction.Moreover,it sorts out the diverse characteristics of those coatings such as their sensing principles,influencing factors,advantages and drawbacks,and fluo-rescence/coloration performances.Second,two kinds of preparation strategies for coatings of defect self-disclosure are introduced,one is grafting indicator groups onto polymer chain segments to prepare coat-ings of intrinsic defect self-disclosure,and the other is to incorporate nano-containers loaded with indica-tor as the functional filler.The differences and limitations of these strategies are compared and analyzed,further focusing on the key role of nanocontainers and their compatibility with different types of coatings of defect self-disclosure.In addition,the corrosion inhibitors,healing agents,and polymer microcapsules in the coatings of defect self-disclosure can not only realize defect indication but also endow their corro-sion self-healing performance for boosting their application in the industrial field.Finally,it is envisioned the development prospect of coatings of defect self-disclosure to provide theoretical guidance for the de-sign and application of the coatings of defect self-disclosure.
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维普
