Stick–slip friction of gecko-mimetic flaps on smooth and rough surfaces
| Autor: | Jacob N. Israelachvili, Sathya Chary, Nicholas Cadirov, Yair Kaufman, Jack Hogan, Saurabh Das, Kimberly L. Turner |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Materials science
Friction Surface Properties Biomedical Engineering Biophysics Bioengineering Slip (materials science) Biochemistry Biomaterials Physics::Fluid Dynamics chemistry.chemical_compound Optics Biomimetics Adhesives Materials Testing Surface roughness Animals Gecko Dimethylpolysiloxanes Research Articles Shearing (physics) biology Polydimethylsiloxane business.industry Adhesiveness Surface forces apparatus Lizards Mechanics biology.organism_classification Silicon Dioxide Biomechanical Phenomena Condensed Matter::Soft Condensed Matter chemistry Adhesive Glass Stress Mechanical business Shear Strength Biotechnology |
| Popis: | The discovery and understanding of gecko ‘frictional-adhesion’ adhering and climbing mechanism has allowed researchers to mimic and create gecko-inspired adhesives. A few experimental and theoretical approaches have been taken to understand the effect of surface roughness on synthetic adhesive performance, and the implications of stick–slip friction during shearing. This work extends previous studies by using a modified surface forces apparatus to quantitatively measure and model frictional forces between arrays of polydimethylsiloxane gecko footpad-mimetic tilted microflaps against smooth and rough glass surfaces. Constant attachments and detachments occur between the surfaces during shearing, as described by an avalanche model. These detachments ultimately result in failure of the adhesion interface and have been characterized in this study. Stick–slip friction disappears with increasing velocity when the flaps are sheared against a smooth silica surface; however, stick–slip was always present at all velocities and loads tested when shearing the flaps against rough glass surfaces. These results demonstrate the significance of pre-load, shearing velocity, shearing distances, commensurability and shearing direction of gecko-mimetic adhesives and provide us a simple model for analysing and/or designing such systems. |
| Databáze: | OpenAIRE |
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