Ron%20Fearing%20work%20on:%20Synthetic%20Gecko%20Spatula%20Array%20Fabrication

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Ron Fearing work on Synthetic Gecko Spatula
Array Fabrication

• http//robotics.eecs.berkeley.edu/ronf/GECKO/inde
  x.html
• M. Sitti and R.S. Fearing. Nanomolding Based
  Fabrication of Synthetic Gecko Foot-Hairs, 2nd
  IEEE Conf. On Nanotechnology, Washington, D.C.
  August 26-28, 2002
• (http//robotics.EECS.Berkeley.EDU/ronf/PAPERS/na
  no_02.pdf)
• News Links http//www.lclark.edu/faculty/autumn/g
  eckonews.html

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Design criterion based on Full papers

• K. Autumn, and et. al. Adhesive force of a
  single gecko foot-hair, Nature, vol. 405, pp.
  681-685, June 8 2000
• Compliant, dry micro/nanoscale, high aspect ratio
  beta-keratin structures
• Hairs go from stalks (micrometer scale) to
  spatular stalks (nanometer scale) by branching
• K. Autumn, M. Sitti, Y. Liang, and et. al.
  Evidence for van der Waals attachment by gecko
  foot-hairs inspires design of synthetic
  adhesive, Proc. Of the National Academy of
  Sciences, 2002.
• Hairs adhere to surfaces via molecular forces
  such as Van der Waals

Thus the focus of this paper is the fabrication
of spatular and setal stalks through Nanomolding
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Fabrication Methods
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Nanorobotic Imprinting

• Single Atomic Force Microscope (AFM)
• Used to imprint flat wax surface
• Molded with polymer and then separated by peeling

Youngs Modulus Pull-off force
Measured Gecko Value 1-15 GPa 50-300 nN
Silicone rubber 0.57 MPa 1809 nN
Polyester resin .85 GPa 29421 nN
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Parallel Fabrication

• Alumina
• Wet-etching combined with length leads to
  hydrophobic hairs sticking together

Material Pore Diamter (µm) Thickness (µm) Pore Density (pores/cm2)
Alumina 0.02-0.2 60 109
Polycarbonate 0.02-20 7-14 105-108
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Conclusions

• Method I
• Relatively indedpendent of material properties
• Repeatable
• Consistent with standard adhesive model

Spatulae on a single gecko seta. (K. Autumn, E.
Florance)

• Method II
• Potential for mass production
• Further optimization such as length and density
  /or external excitation (such as ultrasonic
  vibration) or surfactant for etchtant to minimize
  hydrophobic attraction