Stimuli-responsive epoxy coatings based on mesoporous silica nanocontainers encapsulated by silicate-mediated ellagic acid networks

Purpose This study aims to develop a strategy to improve the pHresponse of the Zn-BTA complexes-capped mesoporous silica nanocontainers (Zn-BTA@MSN) for the construction of the corrosion-resistant smart epoxy coatings. Design/methodology/approach Depending on the promoting effect of silicate on the deposition of ellagic acid (EA) in the weakly basic media, the silicate-mediated EA networks (Si-EA) are deposited to encapsulate the Zn-BTA@MSNs for the formation of Si-EA{Zn-BTA@MSN} nanocontainers. Furthermore, the epoxy coatings incorporated the Si-EA{Zn-BTA@MSN} nanocontainers are constructed for the investigations on the corrosion resistance and the stimuli-responsive performance. Findings Compared with the Zn-BTA@MSNs, the Si-EA{Zn-BTA@MSN} nanocontainers exhibit the higher pH-sensitivity and the more controllable release behavior of inhibitors. At pH > 7, the cumulative release ratio of BTA is lower than 20% after 2 h of extraction. With the decrease of pH, both the release rate and the cumulative release ratio of withinhibitors increases rapidly. Electrochemical and salt spray tests demonstrate that the incorporation of the Si-EA{Zn-BTA@MSN} nanocontainers significantly enhances the corrosion resistance of the epoxy coating. The epoxy coating incorporated with the Si-EA{Zn-BTA@MSN} nanocontainers exhibits the remarkable stimuli-responsive behavior. Originality/value The study presents a novel approach to preparing the highly pH-responsive inhibitor nanocontainers. Moreover, the controllable release of inhibitor for the nanocontainers is significantly improved by the encapsulation of the Si-EA networks.