• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.771-772
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• 2010

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1099-1103
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• 2015

Recently, there have been several studies on the inspiration and application of optimized natural structures. One study introduced a new adhesion method that was inspired by the feet of geckos because of their superior features such as high adhesion strength, ease-of-removal, and they are environmentally friendly. Various micro- or nano-structures were fabricated and tested for gecko-like dry adhesives, but gecko-like dry adhesives that were developed became easily worn from frequent use. In this study, we propose a metal-coating method to improve the durability of gecko-like dry adhesives. We evaluate the initial adhesion strength and durability by performing repeated adhesion tests on a glass plate. The initial adhesive strength of gold-coated micro-structures was 60% of that for non-coated ones. However, the adhesive strength of gold-coated micro-structures was kept as 58% of their initial adhesion strength, while that of non-coated ones was only 40%.

• Tribology and Lubricants
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• v.26 no.2
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• pp.129-135
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• 2010

Geckos have a unique ability to cling to ceilings and walls utilizing dry adhesion. Their foot pads are covered by a large number of small hairs (setae) that contain many branches per seta with a lower level of spatulae. Their fibrillar structure is the primary source of high adhesion. In this study, we construct the adhesion design database for biomimetic adhesive system. A simple idealized fibrillar structure consisting of single array of beams is modeled. The fibers are assumed as oriented cylindrical cantilever beams with spherical tip. We consider three necessary conditions; buckling, fracture and sticking of fiber structure, which constrain the allowed geometry. The adhesion analysis is performed for the attachment system in contact with rough surfaces with different s values for different main design variables-fiber radius, aspect ratio and material elastic modulus and so on. The developed adhesion design databases are useful for understanding biological systems and for guiding of fabrication of the biomimetic attachment system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.673-677
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• 2016

Recently, engineering applications have started to adopt solutions inspired by nature. The peculiar adhesive properties of gecko skin are an example, as they allow the animal to move freely on vertical walls and even on ceilings. The high adhesive forces between gecko feet and walls are due to the hierarchical microscopical structure of the skin. In this study, the effect of metal coatings on the adhesive strength of synthetic, hierarchically structured, dry adhesives was investigated. Synthetic dry adhesives were fabricated using PDMS micro-molds prepared by photolithography. Metal coatings on synthetic dry adhesives were formed by plasma sputtering. Adhesive strength was measured by pure shear tests. The highest adhesion strengths were found with coatings composed of 4 nm thick layers of Indium, 8 nm thick layers of Zinc and 6 nm thick layers of Gold, respectively.