Researchers have developed three-dimensional structures out of liquid metal. Image Credit: Michael Dickey

Researchers have achieved another breakthrough in 3-D printing by developing techniques to print 3-D liquid metal structures which retain their shape at room temperature.

The research was pioneered by a team from North Carolina State University, including recent graduate Collin Ladd and Dr. Michael Dickey, an assistant professor of chemical and biomolecular engineering, with Dickey heaping praise on the graduate in a recent press release:

"He helped develop the concept, and literally created some of this technology out of spare parts he found himself."

The resulting paper has now been published online in the journal ‘Advanced Materials’.

Liquid centre

There are of course often major difficulties when trying to create structures from drops of

liquid, as the separate beads tend to agglomerate together. The research team countered this problem by using a metal alloy of indium and gallium, which reacts quickly with the oxygen in the surrounding air to form a thin skin around a still liquid centre. This allows the structure to retain its shape.

‘In plane’, or two-dimensional, production of metal structures is a relatively straightforward process, however it is a different prospect entirely to create stable and well-structured shapes in all three dimensions.

Multiple techniques

So how was this achieved? The below video gives a great insight into the multiple techniques that were used to achieve this feat, as well as showing us what beetles look like with festive antlers!

In the video the thin oxide 'skin', which is key to maintaining the structural integrity of the liquid metal, can be clearly seen. This allows spherical droplets to be stacked on top of one another, like oranges in the supermarket.

Thin metallic wires are also shown to be extruded using an entertaining pressurized air pulse method, which forms the wire instantaneously. Once vacuum conditions are applied, the wire can be separated from the tube used to produce it.

A further production technique utilises polymer templates, into which the liquid metal is injected. The template is then dissolved, and the desired shape of the metal is retained.

Bendy electronics

This research could be an important breakthrough for the electronics industry, with the potential to enhance the production of conductive contacts and other components within electrical circuits. It could be particularly useful with regards to ‘bendy electronics’, due to the highly stretchable nature of the gallium-indium alloy, which can be seen in the video below.

Following the news last week about the printable bionic ear, 3-D printing is becoming not just a parlour trick, but a genuinely interesting and practical manufacturing solution.

Though the liquid metal required to create these structures is comparatively expensive, home 3-D printers are becoming more and more affordable, and so it may not be long before electronic components can be printed in the comfort of your own home.

Not only that, but according to Dr. Dickey in principle the materials produced can be self-healing – a new manufacturing revolution could be just around the corner.

Original Source: North Carolina State University