A Solarpunk mobile phone, Part 1: A Screen and Chassis made from Wood

Singapore Giant Tree Gardens By Bay

Replacing hard-to-recycle materials in mobile phones with sustainable ones is a lot easier than it would seem. A small change in common practice could help build a sustainable, beautiful world. One more step toward the solarpunk future.

Solarpunk, if you’re not familiar, is a genre based on a possible future where humans live in balance with the environment and continue to increase our technological capability. It focuses on recycleability, sustainability, and cradle-to-cradle thinking about the machines, materials, and systems we create. An ideal system of justice that recognizes human/environmental interaction, where we realize that we are part of the world we live in. Stewardship instead of Domination. It also has a gorgeous aesthetic, which helps sell the vision of cities with integrated forests and clean water. Every part is created with the end goal of recycling its materials, or repairing it, when it is worn out. Any technology that cannot be recycled is avoided — this is the ideal. The future of electric vehicles meshes well with the idea of cities, and smart grids, and renewable energy. In this case, it’s easy to see the big vision. While this ideal is big and beautiful, it hand-waves away some of the smaller choices that happen on the aggregate, many technological, about how we all live our daily lives that might not mesh with that goal. What choices and solutions do we make to get from here to there? I’d like to draw attention to the fundamental problematic piece of technology in our lives: the mobile phone.

Let’s look at the major “parts” of a mobile phone: a printed circuit board with lots of SMD (Surface Mount) components, a battery to power it, and a case with an integrated touchscreen. Every part of a phone has both a human and environmental cost, and possible solutions.

We’ll start with the part you hold in your hand, the case. Typically a cell phone chassis is made of steel or aluminum, various plastics, and has a strengthened glass touchscreen that is mostly integrated into the chassis. The toughened glass is recyclable, but it is attached to the actual “touch screen” which contains the microscopic LEDs and electronics that display images on your phone and register touch signals. The metal portions should be fairly recyclable, but I see few programs (at least in my area) related to recycling phones. The phone companies have some trade in systems in place, but only for more recent models. Some companies have a “cradle-to-grave” process in place, whereby purchasing a new device can be cheaper when sending in the old device. The company manufacturing the device (the “cradle”) has systems in place for what happens to the device once it is no longer being used (the “grave”). But there’s no assurance that the device doesn’t just end up in a landfill. Sending a phone to your local e-Waste collection point doesn’t necessary mean it’s properly recycled either, it could very well end up in a landfill as well, regardless of your intentions. Once you “throw it away”, there’s no guarantee that it will be responsibly recycled.

The problem with current recycling methods is the concept of “away”. When I was a child, dumping motor oil on the ground was considered a bit lazy, but acceptable practice for many. It wasn’t until I was an adult before “Hazardous Waste” collection activities began in communities where I lived. Unfortunately, these frequently result in landfill storage, and not destruction or recycling. How many tons of gold, lead, mercury, cadmium, chromium, etc sit buried in landfills next to undecomposed plastic diapers? I, as a consumer, put my device in a baggie or a drop box, and I walk away. If that device ends up in a landfill is no concern of mine. I did my part as I buy the next phone, I am absolved of my responsibility. But that thinking is what got us into this mess. We need a cradle-to-cradle solution, that every thing made in one cradle, finds its way to being made into something else in another cradle.

The true cradle-to-cradle solution for phones would be the ability to upgrade them and repair them, and easily recycle them when their usability is no longer required. This would minimize the amount of possible waste streams, by having less of the device actually being sent “away” for recycling. Legal protections and systems for the Right to Repair are a good way to encourage repair and reuse, but having repairable devices is also important. It’s a big problem that will require a large number of systemic changes to address.

Let’s find a solution for the case. Steel and aluminum are infinitely recyclable, but the plastics and printed circuit boards (PCBs) in the phone aren’t. That aluminum chassis has to interface with a glass screen, containing a lot of microscopic parts and rare earths. The first thing many people do is immediate attach another screen to the device to protect it. Steel and Aluminum may be recyclable, but they need to be transported somewhere to be recycled. Suppose we could create a phone chasses that could somehow encapsulate the phone itself, AND integrate with the screen? This would allow us to replace the chassis, but leave the screen in place. This way, we could upgrade the chassis, upgrade the interior, but never worry about cracked screens again. While we’re wishing, wouldn’t it be wonderful if that material was also compostable? What material is tough, compostable, waterproofable, and might even be used for a PCB? Wood.

I can imagine the picture in your head now, of a phone made from wood. Someone holding a 2x4 or a log to their ear. I’m sure there’s wood-based slip-covers already in existence, but you still rely on an additional screen protector.

What I am proposing are thin “plastics” made from wood, and compostable epoxy and look nearly identical to today’s devices. The simplest form of this would be epoxy sealed wood stained with various colorants. The material can be grown quickly, milled quickly and cheaply, and dyed/painted/stained/sealed easily. This is much like some of the wooden cases available currently.

But lets dive a bit deeper into some new technology, “transparent wood”. Originally described in a paper by Zhu et al, called “Highly Anisotropic, Highly Transparent Wood Composites”, wood can be turned into a scaffold material with some common chemicals, and then reinforced to make a new material. By stripping away wood’s lignin with readily available caustics, it can then be refilled with transparent epoxy under a vacuum. The wood itself can provide an astounding level of strength, even flexibility to the project. Recently, it was shown that compressed wood in a similar process was strong enough to make body armor ( see https://www.chemistryworld.com/news/bullet-proof-wood-developed/3008627.article ). The only difference with the two processes is compression of the wood once made porous. By using dark or other colored epoxy, you wouldn’t even know that the original material was wood — it could look identical to the device you already carry, be lighter and stronger. This may sound like science fiction, but it’s very real. See https://www.instructables.com/Transparent-Wood/ for an example of a DIY experimenter making transparent wood, and even an action shot of an iPhone screen being used through the wood. I’ve included a few of the author blorgggg’s project images here.

Image from https://www.instructables.com/Transparent-Wood/
Image from https://www.instructables.com/Transparent-Wood/

By choosing environmentally friendly epoxies, we could create a protective phone shell and screen protector made entirely of wood-based materials, which could be easily and cheaply manufactured and replaced, and composted when no longer needed. This chassis could also be used for laptops and other appliances, kind of the way Bakelite was used in the last century. This would drastically reduce the need for aluminum and steel in these devices, decrease weight, and create entire new markets for manufacture. For the non-screen parts, even commercial cellulose sponges could be used as support materials when impregnated with silicone or epoxy.

I supposed the cellulose of a vinegar SCOBY might be another possible material for the screen — which might provide a middle ground between the weaker structured, but increase light transmission capabilities of the paper/epoxy and the cloudier strength of the wood/epoxy. One last thought on an alternative to wood might be fungal mycelium grown on sawdust or other organic “wastes”. It’s fairly spongy already, and might be freezedried and coaxed under vacuum to accept the epoxy.

Another idea, beyond epoxy might be silicone rubber — making a weirdly flexible and strong plastic-like material. While silicone isn’t biodegradable, it can be ground down and re-used in other products and is biologically inert. Not ideal, but the extra cellulose structure might increase its operational lifespan.

I suppose the ideal would be to remove the lignin, convert it to an epoxy/phelic resin in its own right, and then put it back in as a cured strengthener — to take a simple product (wood) and turn it into a much stronger material.

A knock-on side effect of this technology is the possibility of making e-ink or even OLED displays within the “light tunnels” already extant in the wood, so the wood structure could be the supporting microstructure of the display itself. PEDOT:PSS and similar transparent organic inks might also be used to apply this idea to solar panels. It’s really amazing that we could possibly “upgrade” some of our common building materials for devices and appliances to easily sourced and sustainably grown wood or other natural fiber.

Next time: Let’s see what we can do about the printed circuit boards (PCBs)


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