Ron Fearing work on: Synthetic Gecko Spatula Array Fabrication dex.htmlhttp://robotics.eecs.berkeley.edu/~ronf/GECKO/in dex.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, 2002Nanomolding Based Fabrication of Synthetic Gecko Foot-Hairs ( ) –News Links:

Design criterion based on Full papers K. Autumn, and et. al. “Adhesive force of a single gecko foot-hair,” Nature, vol. 405, pp , June Adhesive force of a single gecko foot-hair –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.Evidence for van der Waals attachment by gecko foot-hairs inspires design of synthetic adhesive –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

Fabrication Methods

Nanorobotic Imprinting Single Atomic Force Microscope (AFM) –Used to imprint flat wax surface –Molded with polymer and then separated by peeling Young’s Modulus Pull-off force Measured Gecko Value 1-15 GPa nN Silicone rubber 0.57 MPa180±9 nN Polyester resin.85 GPa294±21 nN

Parallel Fabrication Alumina –Wet-etching combined with length leads to hydrophobic hairs sticking together MaterialPore Diamter (µm) Thickness (µm) Pore Density (pores/cm 2 ) Alumina Polycarbonate Polycarbonate –Used to produce hairs that are shorter and less dense –Hairs have large diameter (6 µm) and low adhesion (60nN)

Conclusions Method I –Relatively indedpendent of material properties –Repeatable –Consistent with standard adhesive model 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 Spatulae on a single gecko seta. (K. Autumn, E. Florance)