SHERP

A nontransferring dry adhesive with hierarchical polymer nanohairs

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Authors
Jeong, Hoon Eui; Lee, Jin-Kwan; Kim, Hong Nam; Moon, Sang Heup; Suh, Kahp Y.
Issue Date
2009-04-07
Publisher
National Academy of Sciences
Citation
Proc Natl Acad Sci USA 106:5639-5644
Keywords
biomimeticsgeckoangled etchingslanted nanohairhierarchical nanohairGECKO FOOT-HAIRFARADAY CAGEASPECT-RATIOATTACHMENT SYSTEMSSURFACESLITHOGRAPHYPLASMAARRAYSDEVICESSILICON
Abstract
We present a simple yet robust method for fabricating angled, hierarchically patterned high-aspect-ratio polymer nanohairs to generate directionally sensitive dry adhesives. The slanted polymeric nanostructures were molded from an etched polySi substrate containing slanted nanoholes. An angled etching technique was developed to fabricate slanted nanoholes with flat tips by inserting an etch-stop layer of silicon dioxide. This unique etching method was equipped with a Faraday cage system to control the ion-incident angles in the conventional plasma etching system. The polymeric nanohairs were fabricated with tailored leaning angles, sizes, tip shapes, and hierarchical structures. As a result of controlled leaning angle and bulged flat top of the nanohairs, the replicated, slanted nanohairs showed excellent directional adhesion, exhibiting strong shear attachment (approximate to 26 N/cm(2) in maximum) in the angled direction and easy detachment (approximate to 2.2 N/cm(2)) in the opposite direction, with a hysteresis value of approximate to 10. In addition to single scale nanohairs, monolithic, micro-nanoscale combined hierarchical hairs were also fabricated by using a 2-step UV-assisted molding technique. These hierarchical nanoscale patterns maintained their adhesive force even on a rough surface (roughness < 20 mu m) because of an increase in the contact area by the enhanced height of hierarchy, whereas simple nanohairs lost their adhesion strength. To demonstrate the potential applications of the adhesive patch, the dry adhesive was used to transport a large-area glass (47.5 x 37.5 cm(2), second-generation TFT-LCD glass), which could replace the current electrostatic transport/holding system with further optimization.
ISSN
0027-8424
Language
English
URI
http://hdl.handle.net/10371/9553
DOI
https://doi.org/10.1073/pnas.0900323106
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Mechanical Aerospace Engineering (기계항공공학부)Journal Papers (저널논문_기계항공공학부)
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