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Soiled adhesive pads shear clean by slipping: a robust self-cleaning mechanism in climbing beetles




Animals using adhesive pads to climb smooth surfaces face the problem of keeping their pads clean and functional. Here, a self-cleaning mechanism is proposed whereby soiled feet would slip on the surface due to a lack of adhesion but shed particles in return. Our study offers an in situ quantification of self-cleaning performance in fibrillar adhesives, using the dock beetle as a model organism. After beetles soiled their pads by stepping into patches of spherical beads, we found that their gait was significantly affected. Specifically, soiled pads slipped 10 times further than clean pads, with more particles deposited for longer slips. Like previous studies, we found that particle size affected cleaning performance. Large (45 μm) beads were removed most effectively, followed by medium (10 μm) and small (1 μm). Consistent with our results from climbing beetles, force measurements on freshly severed legs revealed larger detachment forces of medium particles from adhesive pads compared to a flat surface, possibly due to interlocking between fibres. By contrast, dock leaves showed an overall larger affinity to the beads and thus reduced the need for cleaning. Self-cleaning through slippage provides a mechanism robust to particle size and may inspire solutions for artificial adhesives.

Author(s): Amador, Guillermo and Endlein, Thomas and Sitti, Metin
Journal: Journal of The Royal Society Interface
Volume: 14
Number (issue): 131
Pages: 20170134
Year: 2017
Month: June
Day: 21
Publisher: The Royal Society

Department(s): Physical Intelligence
Research Project(s):
Bibtex Type: Article (article)

DOI: 10.1098/rsif.2017.0134


  title = {Soiled adhesive pads shear clean by slipping: a robust self-cleaning mechanism in climbing beetles},
  author = {Amador, Guillermo and Endlein, Thomas and Sitti, Metin},
  journal = {Journal of The Royal Society Interface},
  volume = {14},
  number = {131},
  pages = {20170134},
  publisher = {The Royal Society},
  month = jun,
  year = {2017},
  month_numeric = {6}