3D printing free standing liquid metal microstructures

NC state 3D prints liquid metals at room temperature
image courtesy michael dickey

researchers at NC state university have developed a way to print liquid metals into three dimensional structures at room temperature. using a type of gallium alloy, the metal stabilizes and forms a thin oxide skin to create volumes that are not possible using conventional liquids, like water. in the demonstration above, the process is expelled as small metal droplets, carefully organized in sequence as an antenna on-top of a roach, illustrating how small the features can be rendered when compared to a familiar reference point. in addition, the resulting components can, in principle, self-heal, allowing for the formation of mechanically stable structures strong enough to stand against gravity and the large surface tension of the liquid. the method is capable of printing wires, arrays of spheres, arches, and interconnected forms.

3D printing of liquid metals at room temperature
video courtesy michael dickey

direct write of free standing liquid metal wires.
image courtesy michael dickey

sequential images in which a syringe needle extrudes liquid metal to form a straight wire on a withdrawn substrate. the oxide skin on the surface of the metal stabilizes the liquid metal wire against gravity and surface tension. the diameter of the wire is 270 μm. the length of the rightmost wire is ∼ 8 mm. in the last image, the wire was intentionally severed by applying vacuum to the syringe.

photographs of the diverse free standing, liquid metal micro structures that can be direct printed at room temperature
image courtesy michael dickey

(a) liquid metal ejected rapidly from a glass capillary forms a thin wire.
(b) these fibers are strong enough to suspend over a gap despite being composed of liquid.
(c) a free standing liquid metal arch.
(d) a tower of liquid metal droplets.
(e) a 3D cubic array of stacked drop-lets.
(f) a metal wire and an arch composed of liquid metal droplets.
(g) an array of in-plane lines of free standing liquid metal fabricated by filling a micro channel with the metal and dissolving away the mold. scale bars represent 500 μm.