Madsen Pirie

It would be nice if we could print circuits onto useful, flexible surfaces.  RFID chips printed directly onto packaging would be useful, and it might be even more useful to be able to print circuits onto paper, cloth or even glass.  A problem has been that conducting inks have not been all that great.  Some are relatively poor conductors, while others needed to be heated to temperatures that ruin what they are printed on.

Now a team at the Technical Institute of Physics and Chemistry in Beijing seems to have made a breakthrough.  They use an alloy of gallium and indium which remains liquid at room temperature.  It is sprayed through the inkjet printer’s nozzles as fine droplets that settle onto the target surface.  The drops oxidize as they move through the air, and the oxides adhere to the target surfaces better than the metal itself does.  Patterns are achieved by masking part of the surface or by moving the printer head in a programmed pattern.  So far they’ve printed conducting circuits on things like cotton cloth, plastic, glass and paper, and even on a leaf.  The process is cheap and could rapidly become widely available.  This raises the prospect of incorporating circuits into all kinds of everyday objects, including the clothes we wear.  When we are praised in future for wearing “smart” clothes, it might just refer to a wholly different meaning…

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