Strippable Catechol-terminated Polyurethane Coating for Large-area Radioactive Decontamination

Rapid decontamination of radioactive surfaces is essential for reducing exposure risks after nuclear accidents and during facility maintenance. Conventional washing or abrasion can generate secondary waste, damage substrates, or require specialized equipment, while commercial strippable coatings often suffer from slow drying and weak adhesion. This study presents a strippable catechol-terminated polyurethane (CPU) coating for radioactive cesium removal.
The CPU coating combines polyurethane toughness with mussel-inspired catechol chemistry. Catechol end groups enhance adhesion and cohesion through multiple interactions, enabling strong contact with contaminated surfaces and clean peeling after drying. The coating can be applied by casting or portable spraying, dries at room temperature, and forms stable films even on vertical surfaces.
Decontamination tests showed that CPU removes both particulate and ionic contaminants. In simulated fallout experiments, CPU achieved high removal efficiencies for Cs⁺, Sr²⁺, and Co³⁺, supported by its hydrophilicity and catechol-mediated affinity for cesium species. Radioactive isotope tests using ¹³⁷Cs confirmed its performance: after 3 h, CPU removed 94.9% of ¹³⁷Cs from stainless steel and 59.1% from rough cement. Compared with a commercial strippable coating, CPU delivered comparable or superior performance in a much shorter time, especially on cement surfaces. Repeated short treatments also improved cement decontamination while limiting substrate damage.
The used CPU film remains stable in water but rapidly dissolves in acetone, enabling post-treatment separation and suggesting a route to reduce secondary radioactive waste. Overall, this work establishes CPU as a rapid, sprayable, strippable, and potentially recyclable coating for radioactive decontamination, offering a scalable strategy for emergency response, nuclear facility decommissioning, and environmental remediation.