Journal
JOURNAL OF THE ROYAL SOCIETY INTERFACE
Volume 12, Issue 108, Pages -Publisher
ROYAL SOC
DOI: 10.1098/rsif.2015.0464
Keywords
friction; van der Waals; biomimetic; Teflon; surface energy
Categories
Funding
- US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering [DE-SC0008068]
- Direct For Mathematical & Physical Scien
- Division Of Materials Research [1105370] Funding Source: National Science Foundation
- U.S. Department of Energy (DOE) [DE-SC0008068] Funding Source: U.S. Department of Energy (DOE)
Ask authors/readers for more resources
Fluorinated substrates like Teflon (poly(tetrafluoroethylene); PIPE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor-Winterton approximation and the Young Dupre equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available