A team from Jiangsu University of Technology, Soochow University, and Ghent University has engineered a transparent, self-healing polyurethane coating that repairs scratches within minutes under heat and simultaneously kills bacteria. The research, published in the Chinese Journal of Polymer Science on October 11, 2025 (DOI: 10.1007/s10118-025-3414-7), introduces dynamic selenonium salts as the key chemistry enabling these combined properties.
Polyurethane coatings are widely used to protect cars, ships, electronics, and public surfaces, but they are prone to scratches, fouling, and microbial attachment, which cloud transparency and weaken surfaces. Traditional self-healing approaches, such as microcapsules, offer only single-use repair, while many antibacterial coatings sacrifice clarity. The new material overcomes these trade-offs by embedding selenonium salts into a polyurethane network via a one-pot synthesis and thermal curing. This dynamic chemistry allows polymer chains to rearrange under heat, giving the coating vitrimer-like reprocessability while remaining robust at room temperature.
In tests, the coating healed visible scratches within one hour at 140 °C, and with slight pressure, recovery time shortened to about 20 minutes. Even after multiple cut-and-remold cycles, the films preserved their chemical structure and mechanical behavior. Antibacterial assays showed that selenonium-containing samples dramatically inhibited E. coli and S. aureus growth, with high-loading formulations nearly eliminating colonies. Scanning electron microscopy revealed ruptured bacterial membranes, confirming a contact-killing mechanism.
Optical measurements demonstrated approximately 90–91% light transmittance, comparable to bare glass, and the coating remained clear after two weeks of simulated seawater immersion with minimal swelling. Pencil hardness reached 1H and adhesion was rated 4B–5B, meeting standards for protective coatings on devices and marine windows. The coating also maintained transparency, structure, and antibacterial function after recycling.
"This coating behaves like a living surface—it can recover from damage and defend itself against bacteria," the authors explained. "The key lies in the dynamic selenonium chemistry, which allows the polymer network to reorganize during healing while keeping the surface hostile to microbes." They added that maintaining transparency and mechanical stability after repeated recycling demonstrates the coating's promise in durable and sustainable material design.
The technology could benefit phone screens, touch panels, underwater lenses, public facilities, medical devices, and ship equipment, where scratches and microbial contamination are daily challenges. Its high clarity means it can coat optical components without image loss, while recyclability supports circular material design. With further scale-up, long-term weathering tests, and flexibility tuning, the coating may help reduce maintenance costs and biofouling in marine or healthcare environments. The work opens the door to next-generation coatings that stay clean, clear, and repairable throughout their lifetime.
Funding was provided by the National Natural Science Foundation of China, the Research Foundation Flanders (FWO), and the European Research Council under Horizon 2020, among others. The study was published in the Chinese Journal of Polymer Science, which has a 2024 Impact Factor of 4.0.
