‘Slippery’ steel provides both durability and anti-fouling

The coating, made from rough nanoporous tungsten oxide, is capable of repelling liquid even after it has been subjected to sustained structural abuse. It was developed in the lab of materials science professor Joanna Aizenberg, whose team has been working on Slippery Liquid-Infused Porous Surfaces (SLIPS) since 2011. The work is published in the journal Nature Communications.

“Our slippery steel is orders of magnitude more durable than any anti-fouling material that has been developed before,” Aizenberg said in a statement.

“So far, these two concepts - mechanical durability and anti-fouling - were at odds with each other. We need surfaces to be textured and porous to impart fouling resistance but rough nanostructured coatings are intrinsically weaker than their bulk analogues. This research shows that careful surface engineering allows the design of a material capable of performing multiple, even conflicting, functions, without performance degradation.”

The coating is applied using an electrochemical technique that deposits an ultrathin film of tungsten oxide islands on to the steel. As each liquid-repelling island is not structurally connected its neighbours, damage to one does not effect the integrity of others, and the steel retains both its durability and its anti-fouling properties.