Literature Insight

First Author: Dr. Xiantong Yan, Assistant Professor, College of Civil and Transportation Engineering, Shenzheng University

Corresponding Author: Professor Hongzhi Cui, College of Civil and Transportation Engineering, Shenzhen University

Summary

Professor Hongzhi Cui’s team has made a breakthrough in anti-corrosion technology for coastal infrastructure. Their work, published in Nature Communications, presents a novel inorganic coating that integrates radiative cooling and superhydrophobicity for dual-path corrosion suppression. By synergistically lowering temperature and blocking chloride ions, the coating simultaneously inhibits corrosion thermodynamics and capillary-driven ion transport. This mutual enhancement—radiative cooling maintains superhydrophobic stability, while superhydrophobicity protects optical performance—outperforms traditional single protection method, offering a new solution for marine infrastructure under thermal‑wetting coupled degradation environments.

Background

Steel corrosion causes enormous economic losses annually (~$2.5 trillion) and is particularly severe for marine concrete structures. Solar heating accelerates chloride diffusion and corrosion kinetics via the Arrhenius effect, while seawater penetration provides a direct transport pathway. Traditional strategies (epoxy coatings, cathodic protection, etc.) target single factors and fail against thermal‑wetting synergy. Existing radiative cooling materials lack chloride resistance, and superhydrophobic coatings cannot suppress thermally driven corrosion. Integrating passive cooling, hydrophobicity, and concrete compatibility in one coating remains a challenge.

Highlights

The team developed a temperature-wetting mediated passive anti-corrosion coating (T‑PAC) with four key innovations:

1. Bilayer design: Carbonated C₂S/BaSO₄ bottom layer (radiative cooling) coupled with hydrophobic SiO₂ nanoparticle top layer (anti‑wetting). Strong chemical bonding with concrete.

2. Spectral regulation: 94.6% solar reflectance and 92.8% atmospheric transparency window emissivity enable sub‑ambient cooling of 4.13 °C, retarding thermal acceleration of corrosion.

3. Superhydrophobicity: Water contact angle of 151.3° and rolling angle <5° effectively block capillary‑driven chloride transport.

4. Mutual enhancement: Cooling improves anti‑wetting stability; superhydrophobicity preserves optical performance through self‑cleaning and waterproofing.

Key Results

Cooling performance: T‑PAC achieves 4.13 °C below ambient under direct sunlight. In simulated solar radiation (1000 W/m⟡), it stays ~14 °C cooler than plain concrete.

Water repellency: Nearly zero seawater absorption under high humidity (RH≈100%). Dynamic droplet rebound within 40 ms.

Corrosion inhibition: After 30 accelerated cycles (equivalent to >76 years of natural splash‑zone exposure), T‑PAC shows virtually no mass loss (<1 g/m⟡) and stable impedance modulus. Corrosion current increases by only 0.02 μA/cm⟡. Radiative cooling alone contributes ~72% of the corrosion rate reduction.

Synergistic mechanism: Cooling stabilizes the Cassie‑Baxter state, preventing wetting transition; superhydrophobicity prevents fouling and maintains high solar reflectance.

Conclusion

This work establishes a new paradigm of thermal‑wetting synergistic corrosion protection, outperforming single‑mechanism barriers. The T‑PAC coating integrates sub‑ambient passive cooling and near‑zero seawater permeation, effectively solving heat‑accelerated corrosion and wetting‑driven ion ingress in marine concrete structures. The design principle can be extended to various infrastructures serving in extreme thermal‑humid environments.

Paper link: https://doi.org/10.1038/s41467-026-71930-x