In a paper titled “Electrohydrodynamic Printing of Silver Nanowires for Flexible and Stretchable Electronics,” published in the journal Nanoscale, the scientists discuss a novel AgNW ink specifically developed for EHD printing, where electrostatic forces are used to eject the ink from the nozzle and draw it to the appropriate site on a printing substrate.
"The printed features can be controlled by several parameters including AgNW concentration, ink viscosity, printing speed and stand-off distance", they explain in the paper, which allows AgNW patterns to be printed on a wide range of substrates including paper, PET, glass and PDMS. What's more, the new ‘ink’ consists of a nontoxic and water-soluble solvent containing silver nanowires that are typically more than 20 micrometres long, ensuring highly conductive, flexible and stretchable circuits.
Examined at the nanoscale, the printed patterns look like densely bundled spaghettis, creating a densely interconnected networks of AgNWs.
The researchers have used the new technique to create prototypes that make use of the silver nanowire circuits, including a glove with an internal heater and a wearable electrode for use in electrocardiography. NC State has filed a provisional patent on the technique.
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