While we all love technology that makes life easier, the waste created from cast-off devices is doing the Earth no favors. E-waste is the fastest growing category of domestic trash, with over 50 million metric tons being produced each year. That equates to roughly 15 pounds of e-waste per person annually. Now, researchers at the University of New York at Binghamton have brainstormed a way to make single-use electronics more environmentally-friendly with biodegradable paper circuit boards.

Researcher holds up an innovative paper circuit board that's naturally biodegradable.

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“Humanity’s excessive production of material waste poses a critical environmental threat, and the problem is only escalating, especially in the past few decades with the rapid development of powerful electronic tools and persistent consumer desire to upgrade to the newest available technology,” the team, led by Professor Soekheun Choi, wrote in a paper published in the ASC Applied Materials and Interfaces journal.

Large pile of e-waste in a junkyard.

“The poor disposability of electronics,” the researchers continue, “is especially an issue for the newly arising field of single-use devices and sensors, which are often used to evaluate human health and monitor environmental conditions, and for other novel applications. Though impressive in terms of function and convenience, usage of conventional electronic components in these applications would inflict an immense surge in waste and result in higher costs.”

Traditional circuit boards are manufactured from resin, glass fibers, and metal wiring, making them somewhat bulky and harder to recycle. That means that millions of single-use circuits in things like personal wearable devices, point-of-care medical devices, and environmental monitors simply get tossed in the trash every day.

Traditional resin-based circuit board.

In response to this issue, the team — assembled from the University’s Bioelectrics and Microsystems Laboratory in the Department of Electrical and Computer Engineering — turned to an exercise in “papertronics.” They created a single-use, amplifier-type electronic circuit board made from renewable and biodegradable materials like paper and wax.

Schematics show the researchers' process for assembling the paper circuit board.

The started by printing out electronic channels using wax onto a single sheet of filter paper. The wax was heated to 266 degrees Fahrenheit for two minutes so it could soak completely through the paper. The next step was to fill in all the areas not covered in wax with both semi-conductive and conductive ink. The team then screen-printed conductive metal components onto the paper before bonding the layers together with Thru-hole technology. Lastly, they cast a gel-based electrolyte at 140 degrees Fahrenheit for 10 minutes onto the sheet.

Flow chart shows the process used to create a printable paper circuit board.
The tiny, flexible circuit board proved effective when it came to resistor, capacitor, and transistor functions. If left unused, it could biodegrade over time with minimal permanent waste left behind — but the team also demonstrated that the board could be completely disintegrated within seconds with just the smallest of flames. And because of the limited amount of materials required, producing these paper circuit boards would likely be very inexpensive, and easily scalable for mass production.

Researchers can burn the paper circuit boards not in use to eliminate waste altogether.

Professor Choi and his team are excited by the potential their creation has to curb e-waste on a global scale. As they explain: “All electronic components are paper-based and integrated on paper-based printed circuit boards (PCBs), innovatively providing a realistic and practical solution for green electronic platforms.”