激光结构化仿生表面

In natural selection, "survival of the fittest" is the prevailing mechanism where organisms have constantly been evolving to adapt themselves to their surroundings. Over billions of years, this evolution process has led to the amazing diversity of biological surfaces with distinctive hierarchical structures and functionality in different organisms. Naturally, these unique surfaces are one of the key reasons that creatures can adequately live in their environment. Learning from these animals and plants would be a judicious idea to design and synthesize new materials with desired properties and functions. A famous example of such attempts was Leonardo da Vinci's keen observations on the anatomy and flight of birds to create sketches of "flying machines" based on his efforts. Ever since the mid-1950s, researchers have been seriously thinking to study the unique structure of biological surfaces at micro/nano scale level to elucidate the underlying mechanism and establish the structure-function relationship of these surfaces in organisms. This has led to the birth of the new science, biomimetics, where people imitate natural models, systems, and elements to solve complex human problems. In recent years, biomimetic has become one of the most crucial approaches in developing new functional materials with a range of applications in areas such as optics, locomotion, construction, architecture, etc. As an important branch of the science, structured biomimetic surfaces have attracted considerable interests in recent years and they have already been applied in various fields ranging from bioengineering, aeronautics/astronautics, modern medicine, national defense, renewable energy to human daily life. For instance, structured biomimetic surfaces can significantly reduce friction, save energy, improve work efficiency and help to reduce the associated environmental pollution with burning extra fossil fuels. Therefore, the fabrication of structured biomimetic surface has gradually become a hot topic in many scientific and engineering subjects. Structured biomimetic surfaces can be fabricated by many methods including electrodeposition, template method, etching, electrostatic spraying, brazing and so on. Due to its advantages of high selectivity, precise control, good reproducibility and negligible pollution, laser fabrication has emerged as an important method for preparing structured biomimetic surfaces. As a kind of non-contact manufacturing process, laser fabrication has shown great potential in mimicking nature and direct laser writing technology has been widely used to fabricate surface with tunable wettability by using nanosecond laser, picosecond laser or femtosecond laser. The periodicities and the patterns of the surface can be a function of the laser parameters including the number of laser beams, the polarization, the angle of incidence and the laser intensity. Consequently, laser fabrication of structured biomimetic surfaces has been able to render uniquely structured surfaces with micro- or nano-sized roughness and hierarchical structures for distinctive functionalities via different laser sources. The current report summarizes the recent progress in laser fabrication of structured biomimetic surfaces and discusses their applications in topics of adhesion/resistance reduction, superhydrophobicity, optics and so on. As we are only in the beginning era of biomimetic technology and applications, it is expected that scientists would continue creating more and more functional biological surfaces in the future, where laser fabrication is believed to an important role therein.