Flexibility and Poisson effect on detachment of gecko-inspired adhesives

Geckos and some insects can easily adhere to and detach from surfaces with micro/nanoscale hair structures on their foot, called setae and spatulas. Here, a model is developed to describe the detachment of the seta. In this model, the seta is assumed to be a beam whose tip adheres to a surface. When normal and tangential forces are applied to the root of the beam, a moment is generated at the contact tip and detachment occurs. The detachment conditions depend heavily on flexibility of the hair. The effects of Young's modulus and aspect ratio of length versus thickness of the beam on the detachment condition are theoretically investigated. The Poisson effect on the detachment conditions was also examined with the experimental results using fabricated silicone rubber beam arrays.