LAUSR

Nature has developed multi-functional geometric structures, and surface textures with excellent tribological characteristics, such as feet of geckos. Geckos have extraordinary abilities to climb walls and even upside down on the ceiling. Studies have revealed that hierarchical structure of gecko’s feet can bear the weight of two humans and this strong adhesion force is mainly generated by weak van der Waals force. This paper reviews the mechanisms and the forces responsible for gecko’s adhesion, and the effect of humidity on adhesion against different hydrophobic/hydrophilic surfaces. The excellent adhesive and frictional properties of gecko adhesion system have inspired many researchers to develop gecko-inspired synthetic adhesives. In this paper, recent development of gecko-inspired synthetic adhesives has been presented in terms of various fabrication methods, different tip structures, and the effect of counter surface roughness as well as design criteria to avoid bunching of nano-structures. The application of synthetic adhesives is also discussed for wall climbing robots and novel applications in the field of space, biomedical and sports accessories.