Synergistic construction of long-lasting slippery antifouling interfaces on Ti alloys via nanoporous structures, low-surface-energy functional layer and lubricant infusion

Ti alloys are widely used in marine engineering, but their long-term performance is severely constrained by surface biofouling. Dynamic slippery surfaces offer a promising antifouling strategy; however, the rapid loss of lubricants under complex marine conditions remains a key bottleneck. Herein, we report a nanopore–low surface energy functional layer–lubricant synergistic strategy to construct a long-lasting liquid-infused antifouling interface on titanium alloys. Ordered three-dimensional nanoporous structures were first fabricated via controlled NaOH etching, providing capillary confinement for lubricant retention, followed by grafting low-surface-energy functional layers to enhance interfacial compatibility. Based on solid–liquid adhesion energy analysis, Krytox 103 was identified as the optimal lubricant for stable infusion. The resulting liquid-infused surface exhibited a significantly reduced friction coefficient (∼0.17) and maintained a high water contact angle (∼103°) after immersion in artificial seawater for 30 days. Antibacterial and anti-algal assays demonstrated adhesion inhibition efficiencies exceeding 90%, while field immersion tests in real marine environments confirmed sustained antifouling performance for up to 50 days. Mechanistic analysis reveals that the synergy between capillary locking within the nanopores and enhanced interfacial compatibility is crucial for long-term lubricant retention and effective suppression of bioadhesion. This work provides a scalable strategy for constructing durable slippery interfaces on titanium alloys and offers new insights into stabilizing lubricants using nanostructured surfaces for marine antifouling and related functional interface applications.