Intelligent liquid

 Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a programmable metafluid with tunable springiness, optical properties, viscosity and even the ability to transition between a Newtonian and non-Newtonian fluid.

The first-of-its-kind metafluid uses a suspension of small, elastomer spheres -- between 50 to 500 microns -- that buckle under pressure, radically changing the characteristics of the fluid. The metafluid could be used in everything from hydraulic actuators to program robots, to intelligent shock absorbers that can dissipate energy depending on the intensity of the impact, to optical devices that can transition from clear to opaque.

The research is published in Nature.

"We are just scratching the surface of what is possible with this new class of fluid," said Adel Djellouli, a Research Associate in Materials Science and Mechanical Engineering at SEAS and first author of the paper. "With this one platform, you could do so many different things in so many different fields."

Metamaterials -- artificially engineered materials whose properties are determined by their structure rather than composition -- have been widely used in a range of applications for years. But most of the materials -- such as the metalenses pioneered in the lab of Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS -- are solid.

"Unlike solid metamaterials, metafluids have the unique ability to flow and adapt to the shape of their container," said Katia Bertoldi, William and Ami Kuan Danoff Professor of Applied Mechanics at SEAS and senior author of the paper. "Our goal was to create a metafluid that not only possesses these remarkable attributes but also provides a platform for programmable viscosity, compressibility and optical properties."

Using a highly scalable fabrication technique developed in the lab of David A. Weitz, Mallinckrodt Professor of Physics and of Applied Physics at SEAS, the research team produced hundreds of thousands of these highly-deformable spherical capsules filled with air and suspended them in silicon oil. When the pressure inside the liquid increases, the capsules collapse, forming a lens-like half sphere. When that pressure is removed, the capsules pop back into their spherical shape.

Source: ScienceDaily