Microscopic modeling of the dynamics of frictional adhesion in the gecko attachment system

Tetsuo Yamaguchi, Nick Gravish, Kellar Autumn, Costantino Creton

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)

    Abstract

    We present a simple microscopic model describing the unique friction behavior of gecko setal arrays as they are dragged on smooth surfaces. Unlike other solids of high elastic modulus that do not stick under van der Waals forces alone, the gecko setal arrays do not require a compressive force to display a drag resistance but rather develop a tensile normal force when they are dragged (J. Experim. Biol. 2006, 209, 3569). We describe this unique behavior with a microscopic model involving curved beam structures at two length scales: at the spatula level, thousands of independent curved beams repeat detachment and reattachment, whereas at the seta level, the curved beam geometry of the seta induces a coupling between the frictional force and the adhesive force that depends on the angle of contact, therefore allowing easy release when the animal needs it. Our model accounts well for the dependence of the drag and adhesion forces on the drag velocity and can also explain macroscopic attachment/ detachment cycles of the setal array.

    Original languageEnglish
    Pages (from-to)3622-3628
    Number of pages7
    JournalJournal of Physical Chemistry B
    Volume113
    Issue number12
    DOIs
    Publication statusPublished - Mar 26 2009

    All Science Journal Classification (ASJC) codes

    • Physical and Theoretical Chemistry
    • Surfaces, Coatings and Films
    • Materials Chemistry

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