仿生取向结构表界面及其摩擦各向异性研究进展

在长期的进化和生存竞争中,自然界生物表界面形成了优异的取向结构来执行传播、攀爬、移动与粘附等诸多行为,而基于形态结构的摩擦各向异性在其中扮演了重要角色。研究自然界取向结构表界面,从而揭示其摩擦各向异性行为和规律,并从中获得灵感,采用物理、化学手段进行仿生构筑和研究,对现代许多科技领域发展新型仿生功能性表界面材料具有重要意义。以露珠草和猪殃殃的倒刺结构、蛇腹部鳞片微结构、壁虎脚掌刚毛微结构为例,详细阐述了具有代表性的自然生物表界面的取向微结构形态及其功能,并对生物表界面产生摩擦各向异性行为的两种机理做了解释。在此基础上,简介了模板法、增材制造等几种仿生取向结构的制备方法,以及基于仿生取向结构的表界面摩擦各向异性研究成果。最后,列举了以蛇的蠕动行进、壁虎的高粘附为仿生对象,构筑具有摩擦各向异性的取向结构表界面,及其在仿生驱动、攀爬和定向输运等方面的应用实例,并展望了仿生摩擦各向异性领域未来的研究重点和发展方向。

Research Advances in Biomimetic Surfaces with Oriented Structures and Its Frictional Anisotropy

In the long-term evolution and survival of the fittest, the biological surfaces/interfaces in nature which are covered with micro- and nanostructures oriented to the supporting layer play crucial roles in the process of spreading, climbing, locomotion, and adhesion due to the resultant frictional anisotropy. Studying the interfaces of natural orientation structure, revealing the anisotropy behavior and laws of friction, and getting inspirations to conduct construction with physical and chemical means and bionic research, are of great significance for the development of new biomimetic functional materials in many fields of modern science and technology. In this review, taking the hook-like spines of the C. Lutetiana and Galium aparine, ventral scales in the snake, and numerous keratinous setae in the gecko feet as examples, the morphology and functions of these natural biological surface/interfaces are introduced detailly, and the two mechanisms of frictional anisotropy based on the oriented structures are explained. On this foundation, the preparation methods including template and additive manufacturing and frictional performance of biomimetic surface/interface with anisotropic structures are discussed respectively. Finally, the applications of the frictional anisotropy surfaces mimicking the fast locomotion of snake and the high adhesion of gecko feet on the biomimetic driving, climbing and directional transportation are exhibited. Accordingly, the perspectives about the research emphasis and the development in the bionic frictional anisotropy field are provided.