Researchers at North Carolina State University have developed a new technique that allows them to print circuits on flexible, stretchable substrates using silver nanowires. The advance makes it possible to integrate the material into a wide array of electronic devices.
Silver nanowires have drawn significant interest in recent years for use in many applications, ranging from prosthetic devices to wearable health sensors, due to their flexibility, stretchability and conductive properties. While proof-of-concept experiments have been promising, there have been significant challenges to printing highly integrated circuits using silver nanowires.
These images show two printed silver nanowire patterns: a horseshoe (top) and Peano curve (bottom) design, with high resolution. The printing technique was used to make a prototype glove containing an internal heater. The bottom shows infrared images of the wearable heater going through an on-off cycle.
Credit: Yong Zhu
Silver nanoparticles can be used to print circuits, but the nanoparticles produce circuits that are more brittle and less conductive than silver nanowires. But conventional techniques for printing circuits don't work well with silver nanowires; the nanowires often clog the printing nozzles.
"Our approach uses electrohydrodynamic printing, which relies on electrostatic force to eject the ink from the nozzle and draw it to the appropriate site on the substrate," says Jingyan Dong, co-corresponding author of a paper on the work and an associate professor in NC State's Edward P. Fitts Department of Industrial & Systems Engineering. "This approach allows us to use a very wide nozzle - which prevents clogging - while retaining very fine printing resolution."
"And because our 'ink' consists of a solvent containing silver nanowires that are typically more than 20 micrometers long, the resulting circuits have the desired conductivity, flexibility and stretchability," says Yong Zhu, a professor of mechanical engineering at NC State and co-corresponding author of the paper.
"In addition, the solvent we use is both nontoxic and water-soluble," says Zheng Cui, a Ph.D. student at NC State and lead author of the paper. "Once the circuit is printed, the solvent can simply be washed off."
What's more, the size of the printing area is limited only by the size of the printer, meaning the technique could be easily scaled up.
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.
"Given the technique's efficiency, direct writing capability, and scalability, we're optimistic that this can be used to advance the development of flexible, stretchable electronics using silver nanowires - making these devices practical from a manufacturing perspective," Zhu says.
The paper, "Electrohydrodynamic Printing of Silver Nanowires for Flexible and Stretchable Electronics," is published in the journal Nanoscale. The paper was co-authored by Yiwei Han, a Ph.D. student at NC State, and Qijin Huang, a former postdoctoral researcher at NC State.
The work was done with support from the National Science Foundation, under grants CMMI-1728370 and CMMI-1333775.
Matt Shipman | EurekAlert!
A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes
20.07.2018 | Science China Press
Future electronic components to be printed like newspapers
20.07.2018 | Purdue University
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences