Bio-inspired Adhesion and locomotion of soft materials

ABSTRACT:
While most man-made adhesives are uniformly thin, smooth layers of viscoelastic glue, natural adhesives at the feet of many arthropods and vertebrates are extensively patterned. These adhesives show strong adhesion on variety of surfaces as well as excellent reusability. They do not get contaminated by dirt, in fact, remain self cleaning. Physics of adhesion on such adhesives is mediated by hierarchical nano-to-microscopic patterns on their surface and sub-surface network of fluidic micro-vessels. Experiments with model adhesives reveal how exactly the coupled effect of surface patterns, sub-surface micro-vessels and the solid-liquid interaction enhances the adhesion strength significantly yet the adhesive remains reusable. In fact, these interactions drive also limbless locomotion in soft objects via various asymmetric effects. For example, a micro-cylinder rolls up an inclined plane, with a velocity which increases with the angle of inclination.