Researchers Develop Hybrid Superamphiphobic Coating
Researchers at the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) recently developed an organic-inorganic hybrid superamphiphobic coating with liquid repellency, self-cleaning, anti-corrosion and anti-icing capabilities.
According to a release from the academy, the coating has both superhydrophobic and superoleophobic properties, meant to protect marine structures from corrosion, icing and other damage.
Corrosion and failure of metallic materials have been a longstanding issue that researchers and engineers are trying to solve, the study explains.
Inspired by the lotus effect, biomimetic superhydrophobic materials with typical non-wetting characteristics at the interface have reportedly exhibited strong potential for corrosion protection.
Though the anti-corrosion function of superhydrophobic materials has been proven by researchers, there are reportedly still several unresolved challenges in the process of moving from the laboratory to practical applications.
Professor Zhang Binbin from IOCAS reportedly led the study, which was published in the Journal of Materials Science & Technology.
The team's new coating has reportedly shown both superhydrophobic and superoleophobic properties, having strong repellency to low surface tension liquids such as water, glycerol, ethylene glycol and peanut oil, with sliding angles all less than 7 degrees.
The corrosion resistance of the coatings was reportedly tested thoroughly with electrochemical impedance spectroscopy, Tafel polarization, salt spray testing and outdoor atmospheric exposure.
According to the release, the results of this produced an increase in the charge transfer resistance and low-frequency modulus of the coating by seven to eight orders of magnitude, enduring 480 hours of neutral salt spray and 2,400 hours of atmospheric exposure, showing strong long-term anti-corrosion potential.
Additionally, the coating also reportedly showed functional integration capabilities in self-cleaning, delayed icing, lossless liquid transportation and substrate applicability.
"We firmly believe that in future research, the continuous improvement of functional integration and long-term stability will remain the focus of this field," said Zhang.
The uniform dispersion of functionalized Al2O3 nanoparticles in the coatings reportedly gives important support to the ultimate realization of the coatings' multifunctional integration characteristics.
The study was financially supported by the Shandong Provincial Natural Science Foundation and the Youth Innovation Promotion Association of Chinese Academy of Sciences.
More from IOCAS
In October 2022, a research team from IOCAS reported a new mechanical robust superhydrophobic coating that could be applied via spray-coating.
The study, published in the journal Materials & Design, was led by IOCAS Professors Hou Baorong and Duan Jizhou.
According to the institute’s release, lotus-inspired superhydrophobicity attracted researchers due to interfacial non-wetting and unique multi-phase contact properties. However, properties such as fragile hierarchical structures, fluorine-containing chemical usage and strict requirements for substrate scopes provided challenges.
As a result, the research team developed the superhydrophobic coating (ZnO@STA@PDMS) with fluorine-free reagents. Additionally, the coating utilized hierarchical rough micro-scale bump-porous structure, nano-scale particles and extremely low surface energy to repel water.
After spray-coated with the fabricated superhydrophobic coating, Q235 carbon steel’s ICorr saw decreases two orders of magnitude, suggesting a “superior” corrosion resistant performance. The |Z|10mHz value of the superhydrophobic coating was reportedly three orders of magnitude higher than the substrate.
Researchers utilized simulated marine atmospheric conditions with high relative humidity to test the coating, recording hygroscopic and deliquescence behaviors of NaCl salt particles. The results revealed that the corrosion damage in the edge of a saline droplet on bare Q235 carbon steel was more severe than interior because of faster ions transfer and abundant oxygen.
Based on this, researchers noted that the superhydrophobic coating possessed “promising” atmospheric corrosion inhibition performance based on the salt-deliquesce and instantaneous self-coalescence phenomenon observed.
The institute reported that the low interfacial adhesion force, low surface energy and air cushion-induced Cassie multi-phase contacts contributed to the saline droplet anti-wetting and remarkable anti-corrosion capability.