Multifunctional magnetorheological elastomers with superior superhydrophobicity and mechanical robustness enabled by magnetic alignment

Superhydrophobic surfaces (SHS) promise multifunctional performance, but practical use is often limited by poor mechanical resilience. Many SHS rely on soft polymer matrices that are structurally vulnerable; water repellency and related functions degrade under stress. This study introduces a novel method to fabricate multifunctional SHS by combining anisotropic magnetorheological elastomers (MREs) with bio-inspired sharkskin microstructures and hydrophobic iron oxide nanoparticle (SHIP) coating. The SHS fabrication involved a two-step process: soft lithography to imprint a sharkskin pattern on a polyurethane (PU) matrix containing SHIP, followed by SHIP deposition during partial curing under a vertical magnetic field. This process promoted the formation of rebar-like chain microstructures and micro–nano hierarchical roughness, enabling durable superhydrophobicity. The resulting coating exhibited a water contact angle of 163° and contact angle hysteresis of 1°, and retained superhydrophobicity after 500 cm of 240-grit sandpaper abrasion (3.3 kPa), water-jet impact, and 90 days of open-air exposure. The new material showed enhanced compressive strength (59.4% improvement from the control), attributed to vertically aligned iron particle chains, and higher loss modulus and loss factor. Collectively, these results demonstrate a robust, multifunctional coating for applications demanding water repellency, toughness, and vibration damping—for example, marine protective surfaces.