The cellulose structure of ordinary plant leaves, with specific treatment, is capable of withstanding high temperatures and serving as a basis for biodegradable circuits.
A research team led by Professor Karl Leo from the Dresden University of Technology (TUD) has developed a nature-inspired solution that could revolutionize electronics production. The Leaftronics project leverages the natural structure of leaves to create biodegradable electronic components.
Traditional printed circuit boards are made using epoxy resin reinforced with fiberglass. These materials are not recyclable and are not biodegradable. Given the enormous volume of electronic waste produced at a rate exceeding 60 million tons annually, there is an urgent need for alternatives.
Pervious studies focused on creating biodegradable natural polymers. However, this approach faced challenges in thermal and chemical resistance. There is a fundamental conflict between the biodegradability that requires weak molecular bonds and the thermal and chemical stability that requires the opposite.
“This research demonstrates that lignocellulosic frameworks derived from leaves can stabilize bio-based polymers processed with solutions, acting as natural limiting environments. Such reinforced films, even those based on gelatin (Tg ~60°C), can withstand processes exceeding 200°C. We show dip-coated ethyl cellulose films for commercially viable soldered circuits. The films offer high flexibility, transparency above 80%, and surface roughness of less than 5.5 nm,” the research abstract states.
The team of researchers has made significant progress in resolving this conflict. Leaftronics utilizes the natural structure of leaves to create biodegradable electronics. They provide a sustainable, efficient, and scalable solution to the global electronic waste problem. This breakthrough was made possible by discovering that the structures of natural leaves, which serve as scaffolding for living cells, can be adapted to reinforce biodegradable polymer films treated with a solution.
“We were surprised to find that these natural frameworks not only support living cells but can also hold together polymers that are processed in a solution, even at relatively high temperatures when these polymers ought to flow,” explains Dr. Hans Klimann, head of the Organic Devices and Systems Group at the Institute of Applied Physics.
The researchers demonstrated that lignocellulose-reinforced polymer films can withstand the microchip manufacturing process and be used in advanced thin-film devices, such as OLED panels. The smoothness of the films, a key requirement for depositing ultra-thin layers of materials, opens the door to producing highly efficient thin-film electronics on such substrates.
“We see that the embedded natural quasi-fractal structure apparently thermomechanically stabilizes polymer films without compromising their ability to biodegrade,” said Dr. Rakesh R. Nair, whose work underpinned the research.
Leaftronics substrates have a carbon footprint three times lower than paper. Once the devices reach the end of their life cycle, the substrates can easily decompose in soil or be recycled in biogas installations, extracting electronic components and valuable materials from the circuits. The research is published in the journal Science Advances.
Source: TechXplore
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