Durable Gradient Liquid-Like Coating via PECVD for Long-Term Pipeline Scale Resistance

Scaling severely impairs the efficiency, safety, and service life of industrial pipelines. While anti-scaling coatings offer an efficient and environmental-friendly solution, their long-term durability remains challenging. Herein, a robust gradient liquid-like coating (gLLC) is fabricated via plasma-enhanced chemical vapor deposition for long-term anti-scaling applications. By integrating a rigid inorganic bulk that gradually transitions to surface enriched in mobile polysiloxane chains, the gLLC combines exceptional mechanical strength (modulus = 14.39 ± 0.17 GPa; hardness = 1.57 ± 0.03 GPa) with dynamic liquid repellency (hexadecane sliding angle = 3°; water sliding angle = 11°). The fluorine-free coating demonstrates potent anti-scaling efficacy against CaCO₃ and CaSO₄ under both static and dynamic conditions, achieving over 75% reduction in scaling mass on stainless steel substrates. Remarkably, the gLLC maintains superior performance over a 90-day dynamic recirculation test, with scale accumulation limited to 1.5 mg cm^-2, representing one of the best long-term performance of anti-scaling coatings reported to date. Furthermore, the gLLC reduces scale deposition by 89% under oil-water emulsion. The outstanding scale resistance is attributed to the low-energy, smooth, and dynamically mobile surface combined with the mechanically durable gradient structure. This work establishes a scalable and environmentally benign strategy for durable anti-scaling surfaces, offering broad potential for deployment in petroleum, chemical, and water treatment industries.