Shark Skin Denticles: From Morphological Diversity to Multi-functional Adaptations and Applications

The energy crisis of the 1970s sparked growing concern over minimizing fuel consumption in water, land, and air transportation. Researchers fascinated by sharks' effortless swimming abilities investigated shark skin denticles and uncovered functions beyond drag reduction, such as antifouling, protection, and bioluminescence. Over the past five decades, significant progress has been made in comprehending drag reduction and antifouling functions of denticle structures; however, the investigation of other functions remains limited. Recent discoveries of diverse denticle morphologies have ignited a keen interest in obtaining morphogroups that can aid other functional studies. This work integrates advances in antifouling, hydrodynamics, aerodynamics, bioluminescence, and protective functions to provide a holistic understanding of their diverse roles. Additionally, this work also dictates multi-functional adaptations of denticles and contributes to the relatively less-explored but essential aspects, such as protective functions and denticle morphogroups. By examining these functions together, this work aims to uncover potential synergies and interactions, facilitating the development of multifunctional materials inspired by shark skin denticles. This work synthesizes shark denticles' functions across research areas, exploring hydrodynamics, antifouling, aerodynamics, protection, and bioluminescence. Additionally, the mechanical properties of white-spotted bamboo shark denticles are investigated and approaches to obtain functional morphogroups are proposed. This study emphasizes the multifunctionality of denticles and their evolutionary adaptations to diverse functions, shedding light on their remarkable capabilities.image