Sam Sattel
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The E-Waste Conundrum – Can Biodegradable Printed Circuit Boards Help?
My fondest memories growing up all involved electronics, from playing Nintendo NES to learning how to build my first computer. Throughout the years, electronics have always seemed so magical, so abundant, and always so new. I’ve gone through more cell phones, video game consoles, and computer components than I can count, but where exactly does all of that stuff go?
As far as most of us are concerned, electronics are like any other piece of waste, disappearing into a black hole. This form of waste, called electronic waste or E-waste, is a huge problem for the world, and for good reasons. What we take for granted as average consumer electronics in the western world get shipped overseas after we discard them, only to wind up in someone’s else’s backyard in China, Africa, or India. On the other side of the world, there’s a different side to the story of electronics, and it’s not a pleasant one.
It Just Keeps Piling Up
Electronic waste is a massive problem, and we send over 20 million tons of it every year to landfills and overseas. And according to ifixit.org, Americans have their part to play with over 3.4 million tons of E-waste generated annually. So what happens to all of those electronics that we just discard?
All those electronics we don’t use anymore? Yeah, they have to go somewhere.
Nearly 80% of it goes straight to a landfill, ready to leach away chemicals into the groundwater. All of this gunk going into our environment can’t end well, considering that our electronics are made up of some nasty metals and gasses, including:
- Mercury – Which is known to be toxic at low doses and can cause kidney and brain damage.
- Cadmium – This chemical element has been proven to cause cancer when found in excess in the body.
- Lead – This one we’re all familiar with, including its ability to create brain damage in children.
- Brominated Flame Retardants (BFRs) – These retardants are known to negatively affect hormonal functions in women.
- Beryllium – You’ll find this being used to make connectors and motherboards, and it also causes cancer in humans.
Look around your house and nearly every electronic that you depend on for your daily survival likely includes many of these metals and chemicals. In developing countries you’ll find men, women, and children breaking down our electronics into their base materials in rather hazardous conditions, all to collect a paycheck. I was surprised to learn all this, I thought we were recycling this stuff?!w
Yeah, About that E-Waste Recycling
Recycling electronics is a bigger problem than meets the eye. As our devices get smaller, lighter and tighter, it’s now a nightmare for recyclers to take them apart and salvage any useful materials. That’s not to mention all of the glue and adhesives that are added to our cell phones and laptops to keep everything held together. All that junk has to be removed manually before any recyclable material can be withdrawn.
Today’s insanely thin laptops, while great for the consumer, are a nightmare to recycle with all the glue and adhesives used.
But the real crux of the recycling dilemma is this – our purchasing patterns for electronics are a bit excessive. New electronics are constantly bombarding the market, with shorter life cycles than ever before. As consumers, this means we’re purchasing the latest and greatest gadget year after year without really considering what will happen to our old stuff. Consider these facts from ifixit.org:
- 1.6 billion cell phones were manufactured in 2012, and are jam packed with some nasty chemicals including arsenic, lead, and flame retardants.
- When purchasing that new cell phone, Americans will on average only keep it for 18 months before getting a new one.
- Even when these old devices are recycled, we lose about 30% from materials that can’t be recovered, that’s huge!
So with both consumer habits getting extreme and our E-waste recycling system in a dire state of being completely overwhelmed, it seems like it’s now time to search for other answers to this problem. And just in time, the biodegradable circuit board arrives, can it solve our problems?
Making the Biodegradable PCB a Reality
While transient electronic components currently exist, putting all of these parts together into an entirely biodegradable circuit board has yet to be conquered, until now. A group of scientists at the University of Illinois Urbana-Champaign Frederick Seitz Materials Research Laboratory set out to create a fully functional PCB that disintegrates when exposed to water.
The Biodegradable System
The scientists determined to create a working circuit board system that could do the following:
- Measure variations in room temperature, and report that data back to an external recording system through a wireless signal.
- The data would need to be very accurate when compared with conventional temperature measurement systems.
- The circuit board would also need to be completely biodegradable, leaving only components and trace materials after being exposed to water.
The results were pretty amazing. This biodegradable circuit board was able to record temperature results that were so accurate that they aligned almost perfectly with temperature reports from a local weather station during a 24 hour period. And when the PCB was immersed in water for only 10 minutes, it completely disintegrated, leaving behind only the components and biodegradable materials. And the best part? The entire thing was flexible.
This circuit board dissolves after being exposed to water for only 10 minutes (Image credit)
How was it made?
Commercial Off-the-Shelf Components (COTS) – These were standard components that you’ll find in any conventional electronic device, including transistors, sensors, and power supplies.
Magnesium Paste – All of these components were attached to the top layer of the PCB (discussed next) with a magnesium paste. By exposing this paste to room temperatures, it created a solid adhesive between the components and PCB while also offering excellent conductivity.
A similar tungsten paste was also used to fill the via holes to provide connectivity to the top and bottom circuit board layers.
Sodium Carboxymethylcellulose (Na-CMC) Substrates – These substrates formed the top and bottom layers of the PCB, measuring a mere 50 µm in thickness.
Polyethylene Oxide (PEO) Bonding Layer – This final layer, measuring only 1µm in thickness, was placed between the two Na-CMC substrates to bond the layers together.
The complete layer stack for a biodegradable PCB. Notice the use of standard components with several biodegradable layers in between a magnesium paste. (Image credit)
A quick fact – the Na-CMC substrates and PEO bonding layers are both in widespread use in the food, pharmaceutical, and cosmetics industries and act as stabilizers. Who knew they’d be just as useful for a PCB!
At the end of their research some bold claims were made that could affect the electronics industry as a whole. These scientists concluded that the materials and methods used in their biodegradable PCB experiments could match the performance found in today’s conventional devices. And with the added capability to have electronic circuits dissolve into non-harmful end products, it’s just a win-win. You can read up on all the fascinating bits in this study here – Biodegradable Materials Printed Circuit Boards report.
The Results Are In, and We Need Change
As the use of electronics becomes more widespread throughout the world, E-waste will continue to grow as a problem that we need to deal with, fast. While we’re still handling the waste of past and present electronic devices, I think we can all agree that it’s time to look towards the future to see how biodegradable electronics can alter how we relate to our natural and human counterparts in this connected electronics ecosystem.
Will this be the next frontier for electronics? It’s possible.
Until this technology becomes more financially viable and available from manufacturers, you can still do your part. Start today by designing electronics that are recyclable and repairable. It will make everyone’s life a little bit easier. Try Autodesk EAGLE for free today to get started.