Denticle-inspired biomimetic non-smooth surfaces: Advances in drag reduction and antifouling applications

Achieving efficient drag reduction and antifouling on high-speed moving surfaces in viscous fluids remains a significant technological challenge. Over millions of years of evolution, natural organisms have developed unique surface microstructures that effectively minimize surface frictional resistance (SFR) and mitigate biofouling in complex environments. Therefore, investigating the intrinsic relationship between the unique surface structures of organisms and drag reduction/antifouling functions can provide innovative inspirations for the design of high-speed surfaces with minimized SFR and biofouling. Compared with air environment, the marine environment is more complicated and considered more representative. Fish, as a typical representative of marine organisms, have excellent fluid dynamics and antifouling capacities. Therefore, the shark—an apex marine predator—was selected as a biological prototype. Beginning with the structural characteristics of sharkskin denticles, the review offers a detailed discussion of fabrication techniques for manufacturing biomimetic denticle-inspired surfaces, Sharklet AF^TM and biomimetic Sharklet patterns. Furthermore, the effects and mechanisms responsible for drag reduction and antifouling in these bioinspired surfaces are systematically examined. Finally, applications of biomimetic non-smooth surfaces in aerospace, biomedicine, and other domains are briefly discussed. The current state of research and future directions in technologies for biomimetic non-smooth surfaces are outlined, highlighting the lack of comprehensive reviews in underexplored fields such as aviation. This study aims to serve as a valuable reference for the design and development of multifunctional biomimetic surfaces.