Researchers have developed a metallic gel that is highly electrically conductive and can be used to print three-dimensional (3D) solid objects at room temperature.
The researcher says that 3D printing has revolutionized manufacturing, but they are not aware of previous technologies that allowed us to print 3D metal objects at room temperature in a single step. This opens the door to manufacturing a wide range of electronic components and devices.
To create the metallic gel, the researchers start with a solution of micron-scale copper particles suspended in water. The researchers then add a small amount of an indium-gallium alloy that is liquid metal at room temperature. The resulting mixture is then stirred together.
As the mixture is stirred, the liquid metal and copper particles essentially stick to each other, forming a metallic gel “network” within the aqueous solution.
The resulting gel can be printed using a conventional 3D printing nozzle and retains its shape when printed. And, when allowed to dry at room temperature, the resulting 3D object becomes even more solid while retaining its shape.
However, if users decide to apply heat to the printed object while it is drying, some interesting things can happen.
The researchers found that the alignment of the particles influences how the material dries. For example, if you printed a cylindrical object, the sides would contract more than the top and bottom as it dries. If something is drying at room temperature, the process is sufficiently slow that it doesn’t create structural change in the object. However, if you apply heat – for example, put it under a heat lamp at 80 degrees Celsius – the rapid drying can cause structural deformation. Because this deformation is predictable, that means you can make a printed object change shape after it is printed by controlling the pattern of the printed object and the amount of heat the object is exposed to while drying.
Ultimately, this sort of four-dimensional printing – the traditional three dimensions, plus time – is one more tool that can be used to create structures with the desired dimensions. But what the researchers find most exciting about this material is its conductivity.
Because the printed objects end up being as much as 97.5% metal, they are highly conductive. It’s obviously not as conductive as conventional copper wire, but it’s impossible to 3D print copper wire at room temperature. And what the researchers have developed is far more conductive than anything else that can be printed.
News Source: NCSU
