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 inspiration for the design of high-speed surfaces with minimized SFRs and biofouling. Compared with the aerial environment, the marine environment is more complex and is considered more representative. Fish, as typical representatives of marine organisms, possess 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 shark-skin denticles, this review offers a detailed discussion of fabrication techniques for manufacturing biomimetic denticle-inspired surfaces, Sharklet®, and biomimetic Sharklet® responsible for drag reduction and antifouling on these bioinspired surfaces are systematically examined. Finally, the 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.