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Earth Hardware

Fully Recyclable Printed Electronics Produced Using Water Instead of Toxic Chemicals (duke.edu) 38

Duke University announces their engineers "have produced the world's first fully recyclable printed electronics that replace the use of chemicals with water in the fabrication process" — bypassing the need for hazardous chemicals.

Electrical/computer engineering professor Aaron Franklin led the study, according to Duke's announcement: In previous work, Franklin and his group demonstrated the first fully recyclable printed electronics. The devices used three carbon-based inks: semiconducting carbon nanotubes, conductive graphene and insulating nanocellulose. In trying to adapt the original process to only use water, the carbon nanotubes presented the largest challenge.... In the paper, Franklin and his group develop a cyclical process in which the device is rinsed with water, dried in relatively low heat and printed on again. When the amount of surfactant used in the ink is also tuned down, the researchers show that their inks and processes can create fully functional, fully recyclable, fully water-based transistors....

Franklin explains that, by demonstrating a transistor first, he hopes to signal to the rest of the field that there is a viable path toward making some electronics manufacturing processes much more environmentally friendly. Franklin has already proven that nearly 100% of the carbon nanotubes and graphene used in printing can be recovered and reused in the same process, losing very little of the substances or their performance viability. Because nanocellulose is made from wood, it can simply be recycled or biodegraded like paper. And while the process does use a lot of water, it's not nearly as much as what is required to deal with the toxic chemicals used in traditional fabrication methods.

According to a United Nations estimate, less than a quarter of the millions of pounds of electronics thrown away each year is recycled. And the problem is only going to get worse as the world eventually upgrades to 6G devices and the Internet of Things (IoT) continues to expand. So any dent that could be made in this growing mountain of electronic trash is important to pursue. While more work needs to be done, Franklin says the approach could be used in the manufacturing of other electronic components like the screens and displays that are now ubiquitous to society. Every electronic display has a backplane of thin-film transistors similar to what is demonstrated in the paper. The current fabrication technology is high-energy and relies on hazardous chemicals as well as toxic gasses. The entire industry has been flagged for immediate attention by the US Environmental Protection Agency.

"The performance of our thin-film transistors doesn't match the best currently being manufactured, but they're competitive enough to show the research community that we should all be doing more work to make these processes more environmentally friendly," Franklin said.

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Fully Recyclable Printed Electronics Produced Using Water Instead of Toxic Chemicals

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  • by 93 Escort Wagon ( 326346 ) on Sunday April 09, 2023 @06:22PM (#63437418)

    The process is water based... but not the transistor. Unless I'm missing something.

    • The other question is how much water it uses and how much can be recirculated. At some point or in some locations providing adequate supplies fresh water becomes a harder challenge than safely disposing of toxic solvents, especially if the purity requirements for the water are very high as they might be in electronics production.

      Add that to the difference in performance of their transistors, which they don't quantify (but is probably more substantial than they suggest) and this might not be as appealing a
      • by Anonymous Coward
        More importantly, does it do net neuterality with AI while demonstrating Bill Gates' wisdom in the matter?

        (Did I leave any out?)
    • Yeah, they seem to be talking about the processes, not the chemical composition of the actual transistor. I think the idea is that water is the solvent, which when the item is dried it leaves the finished pathways. I'm not recalling the chemicals used for making semiconductors themselves (which is what seems to be talked about here) but in general the creation of electronic devices uses a lot of acids and other toxic chemicals, and they specifically make mention of screens being 'low-hanging fruit'. So if y

      • Yeah, they seem to be talking about the processes, not the chemical composition of the actual transistor.

        Actually, an integrated circuit is just layers on layers on layers of conductors, insulators, and semi-conductors. All of which they state are printed using conductive inks and which can by recycled and used again.

        The devices used three carbon-based inks: semiconducting carbon nanotubes, conductive graphene and insulating nanocellulose. Franklin has already proven that nearly 100% of the carbon nanotubes and graphene used in printing can be recovered and reused in the same process, losing very little of the substances or their performance viability. Because nanocellulose is made from wood, it can simply be recycled or biodegraded like paper.

    • by gweihir ( 88907 )

      Yep. And the interconnect (copper) has been recyclable all along. This is not the breakthrough it pretends to be.

      • The generation of "it's not impressive unless it's entertaining" is so profligate and obnoxious is makes me puke.

        You fucks are a cancer on humanity and I just hope mankind can survive long enough for you all to die off.

        • by gweihir ( 88907 )

          You seem to be functionally illiterate. There is no detectable connection between my statement and your "anzwer".

    • The process is water based... but not the transistor. Unless I'm missing something.

      And here I was hoping the CIA had been funding a new super secret spy tool that can easily be destroyed in a crisis.

  • Sounds good (Score:5, Insightful)

    by Retired Chemist ( 5039029 ) on Sunday April 09, 2023 @06:37PM (#63437440)
    The next question is how commercially viable is the process. Just because it does not use solvents does not mean that it does not produce waste. If it is not cost competitive, manufacturers in other countries will not use it.
    • Re:Sounds good (Score:5, Insightful)

      by Baron_Yam ( 643147 ) on Sunday April 09, 2023 @06:50PM (#63437452)

      Given the external costs (poisoning our environment and filling landfills), the next question is "how quickly can we commercialize this process and then legislate it to be mandatory?"

      Doesn't matter if another country uses a different process if you don't allow their products to be sold in yours. You get the US and the EU on board, most of the rest of the world will follow suit.

      • There is no way a ban of cheaper parts made somewhere else is going to work. It never has, it never will. If it did, the market would not be flooded with cheap crappy stuff. The cost of cleaning up the environment is only a factor, if you clean it up. Lots of places do not care.
        • by Zumbs ( 1241138 )
          Lots of places don't care because the largest markets don't care either. If the largest markets were to require that parts are produced in a environmentally friendlier fashion, production facilities around the world would be upgraded. This is not unheard of, e.g. with production of organic foods. Yes, there will be successful cheaters, but such is life.
      • by ceoyoyo ( 59147 )

        There's no reason for regular semiconductor manufacturing to release anything at all into the environment. It does, because it's cheaper that way.

    • Re:Sounds good (Score:5, Insightful)

      by Gravis Zero ( 934156 ) on Sunday April 09, 2023 @07:47PM (#63437524)

      The next question is how commercially viable is the process.

      Actually, the first question should be how much does it cost to clean up the toxic chemicals and who's paying for it? If it isn't the producers then legislation should change that. If nothing else, that will immediately focus the industry on bringing down costs.

      If it is not cost competitive, manufacturers in other countries will not use it.

      An import tax would quickly address that issue. Don't act like these are unheard of problems.

      • The cost of cleaning up the chemicals only matters, if you care. There are plenty of places, where they do not. The US was one until relatively recently, which is why we have so many Superfund sites. Also, I would like to know what is in the water they are using and what is the total environmental impact of their new process.
        • The cost of cleaning up the chemicals only matters, if you care. There are plenty of places, where they do not.

          That's what the import tax is for.

          Also, I would like to know what is in the water they are using and what is the total environmental impact of their new process.

          Read the article and it has a DOI for the paper at the end. https://sci-hub.se/10.1038/s41... [sci-hub.se]

    • Water is commonly used as an industrial solvent. Just FYI. Also, this process most likely requires extremely pure water, but the water they are comparing it to that is "used to deal with toxic compounds" generally is not. So a comparison of energy consumption needs to be made. Especially since most of the "toxic water" is cleaned and reclaimed, through evaporation or other processes, it's not just disappearing.
  • if you use it wrong.
  • "...To make a water-based ink in which the carbon nanotubes don’t clump together and spread evenly on a surface, a surfactant similar to detergent is added...." Whats the chemical compound of these "detergents" ? Most of today's detergents contain certain amounts of environmentally impacting chemicals. How much of these detergent compounds are flushed down the drain? Once again, and article light on details, loads on speculation and "click bait" value.
  • Carbon nanotube (Score:5, Interesting)

    by WaffleMonster ( 969671 ) on Sunday April 09, 2023 @11:13PM (#63437658)

    Carbon nanotubes = Asbestos 2.0

    • by KlomDark ( 6370 )

      Thought you were nuts, but did some reading, and that's not good. I figured the body could break down the nanotubes, but maybe not.

      https://particleandfibretoxico... [biomedcentral.com]

      • The body can't take apart carbon soot, and CNTs are more stable than that, and pointy. Any persistant irritant has the potential to be carcinogenic...

        • by KlomDark ( 6370 )

          Even worse, the shapes and tiny sizes of asbestos fibers and CNTs, allow them to poke right through strands of DNA, which physically causes cancer if poked just right to change the programming but still leaves it able to reproduce. Best case is it just kills a cell.

  • Duke University engineers have created fully recyclable printed electronics that use water instead of hazardous chemicals in their fabrication process. The devices are created using three carbon-based inks: semiconducting carbon nanotubes, conductive graphene and insulating nanocellulose. The team devised a cyclic process in which the device is rinsed with water, dried and printed again - creating fully functional, recyclable water-based transistors. The team was faced with the largest challenge when it cam
  • The ink and substrate has to be robust, it can't start on fire (fr4 is fiber glass). It seems to me that a water based ink isn't going to be robust if the product got wet.

    The ink has to be conductive like copper which is not mentioned in the blurb

    The ink and process also has to be cost effective
    • by ceoyoyo ( 59147 )

      They're talking about making chips. Etched microchips are not robust at all, so you encase them in epoxy or something.

      People have been making boards with conductive ink forever. The copper traces that are used commercially are also not very robust, so they get encased in epoxy.

      Printing semiconductor microcircuits is pretty cool.

  • I can see it now: "It costs pennies more? Then screw you, Mother Earth!"
  • "It would take years to figure out the dynamics of this matrix." "Yes, but you would be rich beyond the dreams of avarice."

"If you lived today as if it were your last, you'd buy up a box of rockets and fire them all off, wouldn't you?" -- Garrison Keillor

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