Printing metallic in midair: 3-D printing and laser annealing of conductive metallic inks without supports may want to lead to customized electronic and biomedical gadgets

"Flat" and "rigid" are phrases normally used to describe electronic devices. but the increasing demand for bendy, wearable electronics, sensors, antennas and biomedical gadgets has led a team at Harvard's Wyss Institute for Biologically inspired Engineering and the toilet A. Paulson faculty of Engineering and applied Sciences (SEAS) to innovate an eye fixed-popping new way of printing complicated metallic architectures -- as although they're apparently suspended in midair.

suggested on line may also sixteen, 2016 inside the proceedings of the national Academy of Sciences, this laser-assisted direct ink writing method lets in microscopic steel, free-status three-D structures to be revealed in one step without auxiliary support fabric. The studies turned into led by means of Wyss middle college member Jennifer Lewis, Sc.D., who's also the Hansjörg Wyss Professor of Biologically stimulated Engineering at SEAS.

"i'm absolutely excited via this modern develop from our lab, which lets in one to 3-d print and anneal bendy metal electrodes and complicated architectures 'on-the-fly,' " said Lewis.

Lewis' group used an ink composed of silver nanoparticles, sending it through a printing nozzle and then annealing it using a exactly programmed laser that applies just the right quantity of power to drive the ink's solidification. The printing nozzle movements along x, y, and z axes and is mixed with a rotary print degree to permit freeform curvature. on this manner, tiny hemispherical shapes, spiral motifs, even a butterfly manufactured from silver wires much less than the width of a hair may be printed in unfastened space inside seconds. the broadcast wires showcase incredible electric conductivity, nearly matching that of bulk silver.

whilst compared to conventional 3-d printing strategies used to manufacture conductive metal capabilities, laser-assisted direct ink writing isn't always only advanced in its capability to provide curvilinear, complex wire patterns in a single step, but additionally within the feel that localized laser heating enables electrically conductive silver wires to be published directly on low-fee plastic substrates.

in line with the observe's first writer, Wyss Institute Postdoctoral Fellow Mark Skylar-Scott, Ph.D., the maximum hard element of honing the method turned into optimizing the nozzle-to-laser separation distance.

"If the laser gets too close to the nozzle during printing, warmth is performed upstream which clogs the nozzle with solidified ink," said Skylar-Scott. "To cope with this, we devised a warmness transfer model to account for temperature distribution alongside a given silver twine sample, allowing us to modulate the printing velocity and distance among the nozzle and laser to elegantly control the laser annealing method 'at the fly.' "

The end result is that the method can produce now not best sweeping curves and spirals however additionally sharp angular turns and directional adjustments written into skinny air with silver inks, starting up close to endless new capacity packages in digital and biomedical gadgets that depend upon customized metallic architectures.

"This state-of-the-art use of laser era to beautify 3-D printing abilities not best conjures up new styles of products, it moves the frontier of solid free-shape fabrication into an thrilling new realm, demonstrating yet again that previously-popular design limitations can be overcome by means of innovation," stated Wyss Institute Founding Director Donald Ingber. M.D., Ph.D., who's additionally the Judah Folkman Professor of Vascular Biology at Harvard medical faculty and the Vascular Biology program at Boston children's medical institution, in addition to Professor of Bioengineering at SEAS.