The most common types of 3D printing involve either extruding melted plastic or using a laser to solidify tiny particles, layer by layer, to slowly build up a solid object. But researchers at the Department of Energy’s Lawrence Berkeley National Laboratory have found a way to radically change that process by 3D printing liquids inside other liquids—and it could mean major advancements in gadget construction.
The printer itself is an off-the-shelf model that the researchers were able to modify by replacing the extruder with a syringe pump feeding a very fine needle that squirts water instead of molten plastic. The machine was then re-programmed to create three-dimensional patterns, as many 3D printers typically only make two-dimensional movements as they build up each layer of a model.
The next innovation, however, was considerably more complicated to perfect. Water has the propensity to break up into droplets as it’s extruded, but the goal of this research was to create continuous liquid structures that hold their shape over time. The researchers chose water as the liquid being extruded, and silicon oil as the base medium, but with slight modifications to both.
Gold nanoparticles in the water attach to polymer molecules in the silicon oil to create a wall keeping the two liquids separate.
Tiny gold nanoparticles were added to the water, while polymer ligands (molecules that bond to a metal) were mixed into the silicon oil. As the water mixture is injected into the silicon oil, the gold nanoparticles interact with the polymer ligands to create a flexible elastic sheath (a sort of supersoap, as the researchers call it) around the water to lock it in place and prevent it from dispersing and losing its unique shape.
3D printing technology seems perpetually on the cusp of revolutionizing countless fields, from manufacturing to fast food, and the downside to this research is that, yet again, we’re not going to see any groundbreaking products come out of it for many, many years. But the potential applications are still fascinating.
The researchers believe this new 3D printing technique could help create news ways to manufacture complicated chemicals, like liquid-based machines directing nanoscale particles to help build new compounds. But even more exciting is the idea of 3D printing liquid electronics that would flex inside stretchable, squishy devices without breaking from being deformed. I’d be first in line for an iPhone that would bounce when dropped, instead of shattering.