Beta-Radiation-Resistant Anticorrosion Coatings Based on Lignin

As humanity ventures beyond Earth, developing radiation-stable coatings from non-fossil sources becomes essential. Beta radiation can significantly harm materials, making it essential to seek resilient, biobased alternatives to work in corrosive environments and high temperatures. Herein, a novel lignin-based coating demonstrating exceptional beta-radiation resistance and anticorrosion properties is presented. The coatings are applied to copper substrates and exposed to 500 kGy electron beam irradiation in air to evaluate their structural and functional stability under extreme conditions. Spectroscopic, microscopic, and thermogravimetric analyses confirm the structural integrity of the coatings post-irradiation. Anticorrosion efficiencies after irradiation are maintained at 99.6% (H₂SO₄) and 99.8% (NaCl) for 61 μm thick films, while thinner 9.5 μm films show 86.4% and 85.7% protection in the respective media, with a ≈4% performance drop post-irradiation. Adhesion strength improves from 0.28 to 0.49 MPa after irradiation, and the water contact angle decreases from 74° to 66°, indicating an increase in hydrophilicity. The superior performance is attributed to the aromatic structure of lignin and its thermally triggered cyclization, which renders it stable against chemical chain scission by oxygen radicals formed in atmospheric conditions under radiation exposure. The performance of thicker films in anticorrosion tests is attributed to a reduced penetration of corrosive agents, due to better morphological integrity. These findings demonstrate the viability of lignin-based coatings as radiation-stable and environmentally sustainable solutions for protecting metal surfaces in harsh environments.