Superhydrophobic materials offer a strategy for developing marine anti-corrosion materials due to their low solid-liquid contact area and low surface energy. However, existing superhydrophobic anti-corrosion materials often suffer from poor mechanical stability and inadequate long-term protection, limiting their practical application in real-world environments.

To address this challenge, a research team led by Prof. ZHANG Binbin from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) has developed a superhydrophobic composite coating with mechanical stability and long-term anti-corrosion performance by utilizing recycled tire rubber (RTR) particles as armored skeleton structure. 

Their findings were recently published in Chemical Engineering Journal.

Inspired by the wear-resistant, weather-resistant, and cushioning properties of multi-layered rubber running tracks, and motivated by concerns over resource waste, environmental pollution, and recycling challenges associated with accumulated waste rubber tires, the researchers designed a triple-layered superhydrophobic anti-corrosion coating using RTR particles as skeleton structure. 

To evaluate its durability, the researchers subjected the RTR armored superhydrophobic composite coating to 1200 cycles of sandpaper abrasion, 450 tape-peeling cycles, and 1050 grams of sand impact. The coating maintained its superhydrophobicity throughout these tests.

Additionally, electrochemical impedance spectroscopy (EIS) revealed that the charge transfer resistance and low-frequency impedance modulus of the coated Q235 carbon steel substrate increased by seven orders of magnitude, while the corrosion current density decreased by five orders of magnitude. The coating showed no signs of failure or corrosion after 840 hours of 3.5 wt.% NaCl immersion and 1680 hours of marine atmospheric exposure, highlighting its long-term anti-corrosion performance.

The designed RTR armored superhydrophobic coating not only enables resource recycling but also provides a new pathway for developing highly wear-resistant and weather-resistant functional protective materials, the researchers noted.

Graphical abstract of the development of highly robust superhydrophobic anti-corrosion coating using recycled tire rubber particles. (Image by IOCAS)