A low-cost, high-yield fabrication method for producing optimized biomimetic dry adhesives

We present a low-cost, large-scale method of fabricating biomimetic dry adhesives. This process is useful because it uses all photosensitive polymers with minimum fabrication costs or complexity to produce molds for silicone-based dry adhesives. A thick-film lift-off process is used to define molds using AZ 9260 photoresist, with a slow acting, deep UV sensitive material, PMGI, used as both an adhesion promoter for the AZ 9260 photoresist and as an undercutting material to produce mushroom-shaped fibers. The benefits to this process are ease of fabrication, wide range of potential layer thicknesses, no special surface treatment requirements to demold silicone adhesives and easy stripping of the full mold if process failure does occur. Sylgard® 184 silicone is used to cast full sheets of biomimetic dry adhesives off 4 diameter wafers, and different fiber geometries are tested for normal adhesion properties. Additionally, failure modes of the adhesive during fabrication are noted and strategies for avoiding these failures are discussed. We use this fabrication method to produce different fiber geometries with varying cap diameters and test them for normal adhesion strengths. The results indicate that the cap diameters relative to post diameters for mushroom-shaped fibers dominate the adhesion properties.

[1]  R. Full,et al.  Evidence for van der Waals adhesion in gecko setae , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[2]  A. Jagota,et al.  Design of biomimetic fibrillar interfaces: 1. Making contact , 2004, Journal of The Royal Society Interface.

[3]  J. P. Sargent,et al.  A practical approach to the development of a synthetic Gecko tape , 2009 .

[4]  Carlo Menon,et al.  Micromask Generation for Polymer Morphology Control: Nanohair Fabrication for Synthetic Dry Adhesives , 2008 .

[5]  M. Meyyappan,et al.  Interfacial energy and strength of multiwalled-carbon-nanotube-based dry adhesive , 2006 .

[6]  Bruce P. Lee,et al.  A reversible wet/dry adhesive inspired by mussels and geckos , 2007, Nature.

[7]  Ronald S. Fearing,et al.  Synthetic gecko foot-hair micro/nano-structures as dry adhesives , 2003 .

[8]  Metin Sitti,et al.  Adhesion and anisotropic friction enhancements of angled heterogeneous micro-fiber arrays with spherical and spatula tips , 2007 .

[9]  A. Mata,et al.  Characterization of Polydimethylsiloxane (PDMS) Properties for Biomedical Micro/Nanosystems , 2005, Biomedical microdevices.

[10]  Kimberly L. Turner,et al.  A batch fabricated biomimetic dry adhesive , 2005 .

[11]  Jiaru Chu,et al.  Fabrication and Adhesive Force Analysis of Biomimetic Gecko Foot-Hair Array , 2006, 2006 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems.

[12]  Metin Sitti,et al.  Enhanced friction of elastomer microfiber adhesives with spatulate tips , 2007 .

[13]  Friction of partially embedded vertically aligned carbon nanofibers inside elastomers , 2007 .

[14]  R. Quinn,et al.  Insects did it first: a micropatterned adhesive tape for robotic applications , 2007, Bioinspiration & biomimetics.

[15]  Metin Sitti,et al.  Gecko inspired micro-fibrillar adhesives for wall climbing robots on micro/nanoscale rough surfaces , 2008, 2008 IEEE International Conference on Robotics and Automation.

[16]  H. Wolf,et al.  High-resolution patterning and transfer of thin PDMS films: fabrication of hybrid self-sealing 3D microfluidic systems , 2004, 17th IEEE International Conference on Micro Electro Mechanical Systems. Maastricht MEMS 2004 Technical Digest.

[17]  Metin Sitti,et al.  Biologically inspired polymer microfibers with spatulate tips as repeatable fibrillar adhesives , 2006 .

[18]  E. Arzt,et al.  The effect of shape on the adhesion of fibrillar surfaces. , 2008, Acta biomaterialia.

[19]  Eduard Arzt,et al.  Contact shape controls adhesion of bioinspired fibrillar surfaces. , 2007, Langmuir : the ACS journal of surfaces and colloids.

[20]  S. Gorb,et al.  WHEN LESS IS MORE: EXPERIMENTAL EVIDENCE FOR TENACITY ENHANCEMENT BY DIVISION OF CONTACT AREA , 2004 .

[21]  M. Sitti,et al.  Gecko-inspired directional and controllable adhesion. , 2008, Small.

[22]  Huajian Gao,et al.  Mechanics of robust and releasable adhesion in biology: bottom-up designed hierarchical structures of gecko. , 2006 .

[23]  Kimberly L. Turner,et al.  A Gecko‐Inspired Reversible Adhesive , 2008 .