Natural materials such as wood and bone owe their high strength to weight ratio not just to the materials from which they’re made, but to the way in which those materials are structured within them. Led by associate professor Rahul Panat, scientists from Washington State University, have devised a 3D printing technique that allows them to mimic such intricate nanoscale structures and the technology could have a number of practical applications.
The process involves first crushing the build material into nanoparticles – although the researchers chose to use silver, many other materials could be utilized.
Those particles are next mixed with a solvent (ethylene glycol) to form an ink, which is then aerosolized to form a mist made up of individual droplets. An aerosol jet printer is subsequently used to shoot those droplets into precise locations within the 3D structure being built, where they cling together. Finally, heat is applied to evaporate the solvent, and sinter the particles together.
The resulting tiny structures are said to be very strong, plus they’re porous and offer a large surface area. So far, they’ve been built in shapes such as micro-scaffolds with trusses, donut-shaped pillars, spirals, and accordion-like electronic connections. The process itself is claimed to be fast and efficient, creating very little in the way of waste – no sacrificial supporting structures are required during the creation of the main structure, for instance.
“This is a groundbreaking advance in the 3D architecturing of materials at nano- to macroscales with applications in batteries, lightweight ultra-strong materials, catalytic converters, supercapacitors and biological scaffolds,” says Panat. “This technique can fill a lot of critical gaps for the realization of these technologies.”