Gecko Adhesion as a Model System for Integrative Biology, Interdisciplinary Science, and Bioinspired Engineering: Video 4

A video from the 2014 review by Kellar Autumn, Peter Niewiarowski, and Jonathan B. Puthoff, "Gecko Adhesion as a Model System for Integrative Biology, Interdisciplinary Science, and Bioinspired Engineering," from the Annual Review of Ecology, Evolution, and Systematics.

Video 4 shows how gecko setae are slippery not sticky when pushed away from the animal, against the direction of curvature of the setae (this is the opposite direction geckos use when they climb). In the lower left, a compression force (blue line) develops during the load step. Friction (shear force) is approximately 0.25 of the compression force, as expected for conventional friction of hard dry materials in contact. There is no measurable adhesion when setae are pushed against their curvature: This is the anti-adhesive direction.