Anticorrosion mechanism of epoxy coating containing mesoporous resorcinol-formaldehyde hollow nanosphere loaded with 8-Hydroxyquinolin

Resorcinol, formaldehyde and tetrapropoxysilane (TPOS) can self- assemble and form nanosphere with core–shell structure in water/ethanol solution. The core is silica and the shell is composed of resorcinol-formaldehyde copolymer and silica. Then, mesoporous hollow nanosphere (MRFHN) with erythrocyte like shape can be prepared after removing silica. Finally, 8-Hydroxyquinoline (8-HQ) is loaded into MRFHN and a high efficiency anticorrosion pigment MRFHN@8-HQ is thus obtained. [Display omitted] •Mesoporous resorcinol-formaldehyde hollow nanosphere (MRFHN) is prepared successfully.•The loading rate of 8-Hydroxyquinoline (8-HQ) in MRFHN (MRFHN@8-HQ) is up to 33%.•8-HQ can release effectively from MRFHN.•Epoxy coating pigmented with MRFHN@8-HQ shows an excellent self-healing function. Mesoporous resorcinol-formaldehyde hollow nanosphere (MRFHN) with erythrocyte like shape was prepared successfully. The average diameter, shell thickness, and specific area of MRFHN are 223 nm, 42 nm, and 73.2 m2/g, respectively. The average loading capacity of 8-Hydroxyquinoline (8-HQ) in MRFHN is 33 % and the sucked 8-HQ can release continuously from MRFHN. MRFHN loaded with 8-HQ (MRFHN@8-HQ) was introduced into epoxy coating to enhance its anticorrosion performance. The results show that epoxy coating pigmented with MRFHN@8-HQ has a higher anticorrosion performance than neat epoxy coating. Especially, epoxy coating containing 4 wt% of MRFHN@8-HQ presents the best anticorrosion performance and self-healing function, and its coating resistance is still maintained at 109 Ω cm2 even after 50-day immersion in 3.5 wt% NaCl solution. Meanwhile, the scratch on coating surface is covered by a thin layer of 8-HQ which can prevent the AA2024 aluminum alloy from corrosion even after 50-day neutral salt spray test. 8-HQ can release from MRFHN and form a compact inhibiting layer on AA2024 aluminum alloy surface, thus the corrosion of AA2024 aluminum alloy is suppressed effectively. MRFHN@8-HQ can be used as a high performance anticorrosion pigment to give epoxy coating a long term protection.