A nontransferring dry adhesive with hierarchical polymer nanohairs

H. E. Jeong, J.-K. Lee, H. N. Kim, S. H. Moon, K. Y. Suh

Research output: Contribution to journalArticlepeer-review

417 Scopus citations

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 (approximately 26 N/cm(2) in maximum) in the angled direction and easy detachment (approximately 2.2 N/cm(2)) in the opposite direction, with a hysteresis value of approximately 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
Original languageEnglish (US)
Pages (from-to)5639-5644
Number of pages6
JournalProceedings of the National Academy of Sciences
Volume106
Issue number14
DOIs
StatePublished - Mar 20 2009
Externally publishedYes

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