For many technologies there seems to come a renaissance as people develop new and interesting ways to utilize the technology. The ever-popular technology of 3D printing seems to be in that renaissance currently as researchers are finding new ways to apply it. For example, those at North Carolina State University have discovered how to print 3D structures made of liquid metal.
Most of the time when pushing a liquid out of a nozzle onto a substrate, you would expect the liquid to gather together into a larger and larger drop. Not so with an alloy of gallium and indium, which is liquid at room temperature, as it oxides when in contact with air. The oxidation layer is firm enough to maintain the original drop's shape, but does not prevent multiple drops from connecting to form a more complex structure. The researchers were able to build tall structures of liquid metal beads, as well as extrude liquid metal wires, capable of conducting electricity.
While it is definitely impressive to see a 3D structure printed in free-space, the researchers found they also could inject the liquid metal into a polymer template, which is then dissolved away to leave the metal exposed. Potentially these techniques could be combined with already established 3D printing methods for some interesting electronics applications.
Source: North Carolina State University