Indentation versus Rolling: Dependence of Adhesion on Contact Geometry for Biomimetic Structures
| Autor: | Zhenping He, Haibin Wu, Chung-Yuen Hui, Anand Jagota, Nichole Moyle |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Friction Contact geometry 02 engineering and technology 010402 general chemistry Elastomer 01 natural sciences Quantitative Biology::Cell Behavior Quantitative Biology::Subcellular Processes Condensed Matter::Materials Science Biomimetics Indentation Electrochemistry General Materials Science Composite material Anisotropy Spectroscopy Isotropy Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics Static friction Elasticity 0104 chemical sciences body regions Shear (geology) Rigid sphere Stress Mechanical 0210 nano-technology |
| Zdroj: | Langmuir. 34:3827-3837 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/acs.langmuir.8b00084 |
| Popis: | Numerous biomimetic structures made from elastomeric materials have been developed to produce enhancement in properties such as adhesion, static friction, and sliding friction. As a property, one expects adhesion to be represented by an energy per unit area that is usually sensitive to the combination of shear and normal stresses at the crack front but is otherwise dependent only on the two elastic materials that meet at the interface. More specifically, one would expect that adhesion measured by indentation (a popular and convenient technique) could be used to predict adhesion hysteresis in the more practically important rolling geometry. Previously, a structure with a film-terminated fibrillar geometry exhibited dramatic enhancement of adhesion by a crack-trapping mechanism during indentation with a rigid sphere. Roughly isotropic structures such as the fibrillar geometry show a strong correlation between adhesion enhancement in indentation versus adhesion hysteresis in rolling. However, anisotropic structures, such as a film-terminated ridge-channel geometry, surprisingly show a dramatic divergence between adhesion measured by indentation versus rolling. We study this experimentally and theoretically, first comparing the adhesion of the anisotropic ridge-channel structure to the roughly isotropic fibrillar structure during indentation with a rigid sphere, where only the isotropic structure shows adhesion enhancement. Second, we examine in more detail the anomalous anisotropic film-terminated ridge-channel structure during indentation with a rigid sphere versus rolling to show why these structures show a dramatic adhesion enhancement for the rolling case and no adhesion enhancement for indentation. |
| Databáze: | OpenAIRE |
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