New surface coating makes steel stronger, safer and durable

The team of Joanna Aizenberg, Professor of Materials Science at Amy Smith Berylson and core faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard University, first developed Slippery Liquid-Infused Porous Surfaces (SLIPS) in 2011 and has since demonstrated a broad range of applications for the super-slick coating. The new SLIPS-enhanced steel is described in Nature Communications.

“Our slippery steel is orders of magnitude more durable than any anti-fouling material that has been developed before,” said Aizenberg. “So far, these two concepts – mechanical durability and anti-fouling – were at odds with each other. This research shows that careful surface engineering allows the design of a material capable of performing multiple, even conflicting, functions, without performance degradation.”

The biggest challenge in the development of this surface was to figure out how to structure steel to ensure its anti-fouling capability without mechanical degradation. The team solved this by using an electrochemical technique to grow an ultrathin film of hundreds of thousands of small and rough tungsten-oxide islands directly onto a steel surface.

“If one part of an island is destroyed, the damage doesn’t propagate to other parts of the surface because of the lack of interconnectivity between neighboring islands,” said Alexander B. Tesler, former postdoctoral fellow at SEAS, current research fellow at Weizmann Institute of Science in Israel and the paper’s first author. “This island-like morphology combined with the inherent durability and roughness of the tungsten oxide allows the surface to keep its repellent properties in highly abrasive applications, which was impossible until now.”

The material could have far-ranging applications, including non-fouling medical tools and devices, such as implants and scalpels, nozzles for 3-D printing and, potentially, larger-scale applications for buildings and marine vessels.

While a multitude of grades of steel have been developed over the past 50 years, steel surfaces have remained largely unchanged. “This research is an example of hard core, classic material science,” said Aizenberg. “We took a material that changed the world and asked, how can we make it better?”

This new academic research work shows how steel has the potential to become ever more resistant to corrosion protecting it and prolonging its lifespan in applications where it comes into direct contact with water.