2012 R&D 100 Winner
MS712_Harvard_SLIPSA well-known example of naturally repellent surfaces, lotus leaves have inspired a host of hydrophobic, or water-repellent, materials. However, they only work predominantly on water.

Taking a cue from an entirely different type of plant, researchers at Harvard University's Wyss Institute for Biologically Inspired Engineering in Cambridge, Mass., designed a synthetic material surface that is capable of repelling immiscible liquids of virtually any surface tension. The plant in question is the pitcher plant, which traps insects by resisting the oils on the bottom of insects' feet. To build Slippery Liquid-Infused Porous Surfaces (SLIPS) based on this ability, scientists infiltrated a functionalized porous/textured solid with a low-surface-energy, chemically inert liquid to form a physically smooth and chemically homogeneous lubricating film on the surface of the substrate. Matching the chemical and physical properties between the porous substrate and lubricant contributes to a stable film that will not be displaced by foreign immiscible liquids. The largely incompressible surface is instrinsically smooth and defect-free down to the molecular scale. Additionally, it is capable of immediate self-repair by wicking into damaged sites in the underlying substrate.

SLIPS can be optimized for high temperature and pressure conditions, and can be used to transport fluids such as crude oil or biofuels; to form ice-resistant coatings; to resist water- and oil-based spray paints; and to fulfill applications that require biocompatibility.

Liquid-repellant coating

Harvard University, Wyss Institute for Biologically Inspired Engineering

Development Team

(l-r): Joanna Aizenberg and Tak-Sing Wong

The Slippery Liquid-Infused Porous Surfaces (SLIPS) Development Team from Harvard University, Wyss Institute for Biologically Inspired Engineering
Joanna Aizenberg, Principal Developer
Tak-Sing Wong