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Nanofiller design combines UV protection and corrosion resistance
Researchers have developed a hierarchical CeO₂/U66@MXene nanofiller that combines strong UV absorption, free-radical scavenging and barrier effects in a single additive. Incorporated into epoxy coatings, it significantly improves resistance to UV ageing and long-term corrosion protection in saline environments.
In marine environments, UV-induced free-radical degradation contributes significantly to the deterioration of organic anticorrosive coatings, limiting their long-term protective performance. A recent study addresses this challenge with the design of a multifunctional epoxy composite coating that combines improved barrier integrity, UV ageing durability and corrosion protection. Central to the concept is a hierarchical CeO₂/U66@MXene nanofiller, produced via a stepwise solvothermal–hydrothermal strategy.
The nanofiller integrates three components: lamellar 2D MXene nanosheets that provide a stable barrier, octahedral UiO-66 metal–organic framework units that offer a microporous scaffold with a high specific surface area, and particulate CeO₂ nanoparticles that supply free-radical scavenging activity. This hybrid architecture combines strong UV absorption with enhanced radical scavenging efficiency, addressing several failure mechanisms simultaneously.
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Retention of surface, mechanical and barrier properties
When incorporated into an epoxy matrix, the resulting CUM/EP composite coating showed markedly improved surface and interfacial performance after accelerated UV ageing. The reduction in water contact angle was limited to 5.7 % for CUM/EP, compared with 44.9 % for neat epoxy, while the loss in adhesion strength decreased from 76.5 % for the reference to 26.1 % for the composite. These results indicate a strong protective effect against UV-induced surface degradation and interfacial weakening.
Electrochemical impedance spectroscopy further confirmed the improved barrier performance. After 30 days of immersion in saline solution, the low-frequency impedance modulus |Z| at 0.01 Hz of the CUM/EP coating remained as high as 2.45 × 10⁹ Ω·cm², exceeding that of neat epoxy by more than two orders of magnitude. The authors attribute the enhanced durability to the combined effects of the 2D MXene barrier, effective UV attenuation and the exposed active sites of the porous framework, which promote CeO₂-mediated radical scavenging and preserve the polymer network during photoageing. The study illustrates the potential of hierarchical nanofiller design to simultaneously address multiple degradation pathways in protective coatings for demanding service environments.
Source: Xia, Y. et al., Free-radical-mediated UV aging suppression and long-term corrosion protection enabled by hierarchical CeO2/U66@MXene-modified epoxy coatings. Progress in Organic Coatings (2026). https://doi.org/10.1016/j.porgcoat.2026.110299
