Researchers reduce enviro-cost of electronic components
By Johanna Pellus, The Canadian Press, StaffElectronics Production / Materials Engineering conductor
Cuttlefish ink could reduce environmental cost of electronic conductor construction, according to findings at Polytechnique Montreal
Montreal researchers are trying to reduce the environmental cost of electronic components, thanks to cuttlefish ink. The materials from the cuttlefish could be used to print melanin, which is used as an electrical conductor. A Quebec team has developed a process to print purified melanin from cuttlefish ink. They published an article in the American scientific journal “Proceedings of the National Academy of Sciences” (PNAS).
Using biobased materials – which come from living organisms – in the world of electronics makes it possible to envisage a different end-of-life for these objects. They could then go the way of compost, rather than wind up in recycling centres or landfills.
“We have to be careful because there are criteria to respect for compostable materials, but there is a good chance that it will be biodegradable and even biocompatible,” said professor Clara Santato of the Engineering Physics Department at Polytechnique Montreal.
In fact, beyond using biobased materials, Santato wants to highlight the fact that it is possible to use electronic waste.
“I think we need to open our minds and think that waste does not exist,” she said. “Waste is just a stage in the life history of a material.”
While cuttlefish ink, which contains a lot of melanin, was used for the study, other perspectives are possible. For example, in the food industry, an insect farm contacted her to see if their melanin-rich residue could be used to make electronic components. While it’s been known for about 40 years that organic molecules can conduct electricity, environmental concerns have led researchers to look at biobased materials, which could be found in waste materials in particular, Santato said.
“This material (waste) is already available, so I don’t need to go to a chemical industry to synthesize it,” she added.
Recipe for conductivity
Another reason melanins, brown-black pigments made of rings of carbon atoms, have been little used until now: their lack of solubility, which makes the material difficult to process. The Polytechnique team, in partnership with the Institute of Graphic Communications and Printability, has succeeded in overcoming this problem with a recipe that makes melanin from cuttlefish ink soluble.
With a few ingredients and a binding agent, this mixture, once printed, forms a three-dimensional conductive network that can be used in electronic components. It is the melanin nanogranules, derived from the cuttlefish ink, that allow the electricity to be transmitted.
“Paradoxically, our interest in developing technologies has helped us in the fundamental,” said Santato. Indeed, those years of work on melanins led to a discovery about the conductivity of organic molecules. “This is one of the first times that a biobased organic material carries electrons and not ions,” she said, noting that there is no absolute first time, as the research builds on previous knowledge.
“It’s not that in five years, microprocessors are going to be organic,” said Santato. “But there are plenty of applications for which we can think of moving towards something more environmentally friendly, for example, sensors in the oceans, where we can’t collect at the end of life.”
She cites humidity and temperature sensors, oil loss sensors from boats, among others.
“You can’t go after these sensors afterwards, so you have to design them degradable,” she said.
Later, she thinks it will be possible to develop chemical sensors and perhaps devices and integrated circuits. She specifies, however, that for functions where speed is sought, silicon and inorganic materials will always win for chemical bonding reasons.
“In other cases, organic (materials), because they are degradable, because they are flexible, because they can be printed – not like silicon – will have their share,” she said.
The only downside for now is that the binder used – polyvinyl butyral (PVB) – is not biodegradable. The team of researchers is nevertheless working to find an alternative that will make it possible for an entire electronic component based on cuttlefish ink or other biobased materials to end its life in compost.
Other families of molecules are also being studied, such as tannins for electrochemical energy storage and chlorophylls, which were analyzed in the 1970s-1980s, particularly for their use in solar energy.
“We have more knowledge and sophisticated equipment in 2022 than in 1980. We can arrange the molecules much better than 40 years ago,” the professor said.
She hopes that the “waste” of the forest industry, especially in Quebec, can be used to produce electronic components.