Coordination-dynamic urushiol-metal topographies enable on-demand switching between parahydrophobic and...

In the field of smart interface materials, developing surfaces that can dynamically switch between the lotus leaf effect and the rose petal effect is crucial for achieving multi-functional applications. However, existing strategies are often limited by poor stability, the need for exogenous modifiers or complex pre-designed structures. We hypothesize that a coordination-dynamic strategy, based on the structural reconstruction of urushiol-metal networks, can serve as a universal and endogenous method to create surfaces with on-demand switchable wetting states (parahydrophobic/superhydrophobic), eliminating the need for exogenous modifiers. To test this hypothesis, we adjusted terminal deposition layers (Fe³⁺ vs. urushiol) in sequential assembly cycles onto diverse substrates, tailoring their micro-nano architectures and systematically validating the resulting wetting states through contact angle goniometry, high-speed imaging, and wetting mechanism analysis. Our findings demonstrate that terminal Fe³⁺ layers generate micro-nano composite structures stabilized in the Cassie-Baxter state (water contact angle (WCA) 156°, adhesion 95.7 μN), whereas terminal urushiol layers produce micrometer-scale roughness in a hybrid wetting state (WCA 158°, adhesion 129.6 μN). Robustness tests confirm that the surfaces retain >95% hydrophobicity after 300 peel cycles, 20 abrasion cycles, and 7-day UV exposure. The modifier-free switching mechanism enables versatile applications, such as lossless droplet transfer driven by adhesion differential, visual microreactors for monitoring interfacial kinetics, near-zero bacterial adhesion, high-efficiency oil-water separation (99.93% efficiency, flux 11.7 × 104 L·m^-2·h^-1), and Zn²⁺-enhanced hemostasis with clot self-detachment. This coordination-dynamic platform outperforms prior urushiol-based coatings by achieving reversible wetting states without relying on external additives, offering a substrate-agnostic paradigm for smart interfacial design.