Scientists from China’s Tianjin University are creating functional liquid metal circuits that can be laser printed onto a variety of surfaces.

Instead of using a modified inkjet or 3D printer to print a special alloy of gallium metal that is liquid at room temperature, the team chose to print the circuits using a desktop laser printer.

To fabricate the circuits, the team laser printed out a connected design onto heat-transferrable thermal paper. The ordinary laser printer dispensed a carbon-based toner, which was then transferred to a pane of glass via heating. The toner patterns reportedly roughened the surface and formed a hydrophobic air gap between the carbon and the liquid metal, which prevented the metal from adhering when brushed on top. Consequently, the electronic ink pattern adhered only to the exposed parts of the surface.

In the lab, the team demonstrated that the circuits could then be applied directly to smooth surfaces, such as those on a plastic soda bottle, for instance.

Once applied to a variety of surfaces, the researchers suggest that the liquid metal circuits performed as intended — for displaying images, RFID tagging or for sensing temperature and sound.

The liquid metal laser printed circuits are detailed in the article, Thermal Transfer-Enabled Rapid Printing of Liquid Metal Circuits on Multiple Substrates, which appears in the journal ACS Applied Materials & Interfaces.

More information on the laser printed circuits is available in the accompanying video that appears courtesy of the American Chemical Society.

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