Experimental research of load effect on the anisotropic friction behaviors of gecko seta array

Abstract

The load effect on the anisotropic friction property of gecko seta arrays have been experimentally investigated on a homemade micro adhesive and friction force detect device with isolated seta arrays. The result shows that when sliding against the direction of the seta curvature to grip out, the friction force is proportional to the normal load with a friction coefficient of about 0.6. When sliding along the direction of the seta curvature to grip in, the normal preload force could be fully or partly transformed into adhesion force and repulsive force while friction force rapidly rose with the increment of the applied preload. Under the same normal preload, the lateral friction force in grip in is more than twice of that in grip out. These properties of anisotropy in friction and adhesion are determined by the micro and nano-structures of setae.