Super Slippery Surfaces Inspired by Nepenthes Pitcher Plants
"How the slick strategy of pitcher plants inspire a new coating that repels almost everything?"
Examples from nature
Pitcher plants have developed an efficient insect-trapping strategy through the use of a highly slippery surface (Bohn & Federle, PNAS 2004, 101, 14138 – 14143). The surface repels the insect’s oily feet, indicating that similar strategy could be used for designing ultra-repellent surfaces. At the heart of the plants’ excellent repellency lies on a thin protective liquid film locked in place by micro-textures. Since a liquid surface is inherently smooth, self-healing, incompressible, and can be chosen for optical transparency, the novel repellent strategy of pitcher plants offers many outstanding features that cannot be matched by the state-of-the-art liquid repellent surfaces.
SLIPS: A bioinspired slippery surface that repels almost everything
Inspired by the Nepenthes pitcher plants, a synthetic version of the slippery surface was developed during my postdoctoral research at Harvard. The material itself was coined as Slippery Liquid-Infused Porous Surfaces (SLIPS). SLIPS consist of nano/microstructured substrates infused with a lubricating fluid, where the lubricant is locked in place by the substrate and forms a stable, defect-free, inert “slippery” interface. This surface outperforms its natural counterparts and state-of-the-art synthetic surfaces in its capability to repel various simple and complex liquids (water, hydrocarbons, crude oil, and blood); maintain low contact angle hysteresis; restore liquid-repellency after physical damage rapidly; resist ice adhesion; and function at high pressures. With all of these properties (see videos below), SLIPS will find important applications in fluid handling and transportation, optical sensing, medicine, and as anti-icing, self-cleaning and anti-fouling surfaces operating in extreme environments.
Watch SLIPS in Action
Insect Repellency - Direct Mimicry of Nature!!
Easy-clean Surface for Biofilm
Further Readings and Videos:
1. EmTech Talk about SLIPS (3 min), MIT Media Lab, Cambridge, MA (Sept 23, 2014).
2. Tak-Sing Wong, Sung Hoon Kang, Sindy K. Y. Tang, Elizabeth J. Smythe, Benjamin D. Hatton, Alison Grinthal, and Joanna Aizenberg, “Bioinspired Self-Repairing Slippery Surfaces with Pressure-stable Omniphobicity”, Nature, vol. 477, pp. 443 – 447 (2011).
3. Alex Epstein, Tak-Sing Wong, Rebecca Belisa, Emily Marie Boggs, and Joanna Aizenberg, “Liquid-Infused Structured Surfaces with Exceptional Anti-Biofouling Performance”, Proceedings of National Academy of Sciences, USA, vol. 109, pp. 13182 - 13187 (2012).
4. Philseok Kim, Tak-Sing Wong, Jack Alvarenga, Wilmer Adorno, and Joanna Aizenberg, “Liquid-Infused Nanostructured Surfaces with Extreme Anti-Ice and Anti-Frost Performance”, ACS Nano, vol. 6, pp. 6569 - 6577 (2012).
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Copyright by Tak-Sing Wong 2013. All rights reserved.
Department of Mechanical and Nuclear Engineering
Materials Research Institute
Huck Institutes of the Life Sciences
The Pennsylvania State University, University Park, PA 16802