Sarracenia’s Super Slippery Surface

Pitcher plants, scientific names Sarracenia and Nepenthes, are carnivorous plants that use their pitcher-like shape and slippery inner lining to trap their prey in a pool of digestive liquid. Once prey touches the outer edge of their “pitcher” they can’t help but slide down the walls towards their imminent death.

The inner coating in pitcher plants is so slippery that it repels water, oil, honey and can even resist bacteria and ice formation.  The unusual surface of these plants features a microtextural roughness that locks in a lubricating layer of water which repels oils on insects’ feet, so they slide to their end. This slippery inner lining served as inspiration for a materials science lab to create SLIPs, or Slippery Liquid-Infused Porous Surfaces.

SLIPs is a surface consisting of Teflon nano-fibers infused with water and oil repellent lubricating liquid. Prior models for slippery surfaces had been lotus leaves, which utilized their shape and surface coating to repel water, but not all liquids like oils. SLIPs, on the other hand, repel all tested liquids of different compositions and viscosities. This new omniphobic material is also self-cleaning and self-healing. These surfaces are aimed to improve for biomedical fluid handling, for fuel transport, and as a surface that repels ice, which can be used to reduce energy consumption in refrigeration.

Building on SLIPs, there are new ideas in the field that extend this technology further to create a new glass coating that repels nearly everything. The technology is still being improved, but they currently prevent water, oil or octane from sticking to the surface, but it can also prevent fog from forming on glass. That means that systems that need to remain frost-free, like airplanes, power lines, and cooling systems, could be kept clear of frost in the winter. Solar panels can be coated to be more efficient, windows can stay clean indefinitely, glasses can be smudge-free and more difficult to break, and medical diagnostic devices can be coated to reduce the risk of infection and sterility.