An evaluation of the adhesive capabilities of dry adhesive gecko tapes produced using diffraction gratings

Abstract

Certain types of geckos can scale walls, and dry adhesives called “gecko tape” have been developed to reproduce these abilities. However, many of these gecko tapes are difficult and inefficient to produce, especially in large quantities or sizes. This project aims to produce gecko tapes by casting 2-part silicone onto diffraction gratings of various line densities and evaluate the resulting gecko tape’s performance. It was hypothesized that the maximum sliding force of a piece of gecko tape will increase proportionally to the diffraction grating line density. It was also hypothesized that as the angle between the force direction and the interface between the gecko tape and the surface increases, the force required to fully detach the gecko tape off the surface will decrease. These hypotheses were made based on the understanding of an increased line density that results in increased attractive van der Waals forces between the gecko tape and the attached surface, and an increased peeling angle that results in decreased van der Waals forces. Overall, the data collected supported the hypotheses. The maximum sliding force of the gecko tapes increased proportionally to the diffraction grating line density in a linear fashion. The maximum peeling force of 1800linesmm-1 gecko tapes exponentially decreased as the peeling angle increased from 0° to 90°. Gecko tapes produced using an 1800linesmm-1 diffraction grating had an average maximum sliding force of 0.28Ncm-2 and an average maximum peeling force of 2.34N at a 0° angle. More extensive research could be done to better understand the properties of diffraction grating gecko tape, which would allow further directions of research on biomimetics to be justified.