Suspended Kirigami Surfaces for Multifoulant Adhesion Reduction

High foulant adhesion remains a critical issue in a wide range of industries, such as ice accretion on aircraft, biofoulants on ships, wax build-up within pipelines, and scale formation in water remediation. Previous anti-fouling surfaces have only shown promise for reducing the adhesion of a single foulant system; a multi-foulant anti-fouling technology remains elusive. Here, we introduce a mechanical metamaterial-based approach to develop anti-fouling surfaces applicable to a wide range of fouling substances. The suspended kirigami inverted nil-adhesion surfaces, or SKINS, show significantly reduced adhesion of ice, different waxes, dried mud, pressure-sensitive adhesive tape, and a marine hard foulant simulant. SKINS mimic the wrinkling of hard films adhered to soft substrates. Foulant adhesion can be minimized by this wrinkling, which may be controlled by tuning the kirigami motif, sheet material, and foulant dimensions. SKINS reduce adhesion mechanically and were found to be independent of surface energy, enabling their fabrication from commonplace hydrophilic polymers like cellulose acetate. Optimized SKINS exhibited extremely low foulant adhesion, for example, ice adhesion strengths less than 5 kPa (a >250-fold reduction from aluminum substates), and were found to maintain their performance on curved surfaces like transmission cables. The low foulant adhesion persisted over 30 repeated foulant deposition and removal cycles, demonstrating the anti-fouling durability of SKINS. Overall, SKINS offers a previously unexplored route to achieving low foulant adhesion that is highly tunable in both geometry and material selection, is applicable to many different fouling substances, and maintains extremely low foulant adhesion even on complex substrates over large fouled interfaces.