Nature-inspired surface topography: design and function

Learning from nature has traditionally and continuously provided important insights to drive a paradigm shift in technology. In particular, recent studies show that many biological organisms exhibit spectacular surface topography such as shape, size, spatial organization, periodicity, interconnectivity, and hierarchy to endow them with the capability to adapt dynamically and responsively to a wide range of environments. More excitingly, in a broader perspective, these normally neglected topological features have the potential to fundamentally change the way of how engineering surface works, such as how fluid flows, how heat is transported, and how energy is generated, saved, and converted, to name a few. Thus, the design of nature-inspired surface topography for unique functions will spur new thinking and provide paradigm shift in the development of the new engineering surfaces. In this review, we first present a brief introduction to some insights extracted from nature. Then, we highlight recent progress in designing new surface topographies and demonstrate their applications in emerging areas including thermal-fluid transport, anti-icing, water harvesting, power generation, adhesive control, and soft robotics. Finally, we offer our perspectives on this emerging field, with the aim to stimulate new thinking on the development of next-generation of new materials and devices, and dramatically extend the boundaries of traditional engineering.