Rate-dependent frictional adhesion in natural and synthetic gecko setae

Nick Gravish, Matt Wilkinson, Simon Sponberg, Aaron Parness, Noe Esparza, Daniel Soto, Tetsuo Yamaguchi, Michael Broide, Mark Cutkosky, Costantino Creton, Kellar Autumn

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

Geckos owe their remarkable stickiness to millions of dry, hard setae on their toes. In this study, we discovered that gecko setae stick more strongly the faster they slide, and do not wear out after 30 000 cycles. This is surprising because friction between dry, hard, macroscopic materials typically decreases at the onset of sliding, and as velocity increases, friction continues to decrease because of a reduction in the number of interfacial contacts, due in part to wear. Gecko setae did not exhibit the decrease in adhesion or friction characteristic of a transition from static to kinetic contact mechanics. Instead, friction and adhesion forces increased at the onset of sliding and continued to increase with shear speed from 500 nm s-1 to 158 mm s-1. To explain how apparently fluid-like, wear-free dynamic friction and adhesion occur macroscopically in a dry, hard solid, we proposed a model based on a population of nanoscopic stick-slip events. In the model, contact elements are either in static contact or in the process of slipping to a new static contact. If stick-slip events are uncorrelated, the model further predicted that contact forces should increase to a critical velocity (V*) and then decrease at velocities greater than V*. We hypothesized that, like natural gecko setae, but unlike any conventional adhesive, gecko-like synthetic adhesives (GSAs) could adhere while sliding. To test the generality of our results and the validity of our model, we fabricated a GSA using a hard silicone polymer. While sliding, the GSA exhibited steady-state adhesion and velocity dependence similar to that of gecko setae. Observations at the interface indicated that macroscopically smooth sliding of the GSA emerged from randomly occurring stick-slip events in the population of flexible fibrils, confirming our model predictions.

Original languageEnglish
Pages (from-to)259-269
Number of pages11
JournalJournal of the Royal Society Interface
Volume7
Issue number43
DOIs
Publication statusPublished - Feb 6 2010

Fingerprint

Sensilla
Lizards
Adhesives
Adhesion
Stick-slip
Friction
Wear of materials
Silicones
Mechanics
Polymers
Kinetics
Toes
Fluids
Reproducibility of Results
Population

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering

Cite this

Gravish, N., Wilkinson, M., Sponberg, S., Parness, A., Esparza, N., Soto, D., ... Autumn, K. (2010). Rate-dependent frictional adhesion in natural and synthetic gecko setae. Journal of the Royal Society Interface, 7(43), 259-269. https://doi.org/10.1098/rsif.2009.0133

Rate-dependent frictional adhesion in natural and synthetic gecko setae. / Gravish, Nick; Wilkinson, Matt; Sponberg, Simon; Parness, Aaron; Esparza, Noe; Soto, Daniel; Yamaguchi, Tetsuo; Broide, Michael; Cutkosky, Mark; Creton, Costantino; Autumn, Kellar.

In: Journal of the Royal Society Interface, Vol. 7, No. 43, 06.02.2010, p. 259-269.

Research output: Contribution to journalArticle

Gravish, N, Wilkinson, M, Sponberg, S, Parness, A, Esparza, N, Soto, D, Yamaguchi, T, Broide, M, Cutkosky, M, Creton, C & Autumn, K 2010, 'Rate-dependent frictional adhesion in natural and synthetic gecko setae', Journal of the Royal Society Interface, vol. 7, no. 43, pp. 259-269. https://doi.org/10.1098/rsif.2009.0133
Gravish N, Wilkinson M, Sponberg S, Parness A, Esparza N, Soto D et al. Rate-dependent frictional adhesion in natural and synthetic gecko setae. Journal of the Royal Society Interface. 2010 Feb 6;7(43):259-269. https://doi.org/10.1098/rsif.2009.0133
Gravish, Nick ; Wilkinson, Matt ; Sponberg, Simon ; Parness, Aaron ; Esparza, Noe ; Soto, Daniel ; Yamaguchi, Tetsuo ; Broide, Michael ; Cutkosky, Mark ; Creton, Costantino ; Autumn, Kellar. / Rate-dependent frictional adhesion in natural and synthetic gecko setae. In: Journal of the Royal Society Interface. 2010 ; Vol. 7, No. 43. pp. 259-269.
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