Writing about cleantech and Wisconsin is usually kind of a drag, what with Governor Scott Walker’s notorious hostility to clean technology and climate science and all. However, every once in a while a glimmer of light bursts through the Koch-fueled pall, and this week the Intertubes have been all abuzz over a new wood computer chip — wood, as in renewable and biodegradable — developed by a team of researchers at the University of Wisconsin-Madison and the US Department of Agriculture, with an assist from China’s School of Electronic Engineering, University of Electronic Science and Technology in Chengdu.
Before you remind us that Governor Walker does support biofuel, our friends over at Mother Jones already reminded us about that and a whole lot of other things, too (and so did Esquire). However, it seems that Walker’s interest in biofuels only extends to outdated, first-generation biofuels, namely corn ethanol. So, let’s leave that aside and take a look at these fabulous new wood computer chips.
Why Wood Computer Chips?
If the idea of a wood computer chip seems kind of gimicky, guess again. The whole idea is to address the two huge problems besetting the electronics industry, and by extension, us: the gobbling up of non-renewable resources, and the spitting out of vast amounts of non-recyclable waste, some of it toxic.
The problem is accelerating with lightning speed, as wireless and computer-assisted devices make their way into every nook and cranny of modern life.
Just to take one example, look at next-generation manufacturing. During last week’s tech tour of Germany, we got the rundown on the country’s push for “Industrie 4.0,” a robot-assisted, modular manufacturing concept dubbed SmartFactoryKL. The idea is to embed each product with a chip at the beginning of the assembly line, and at each stage the chip tells the module what to do with the product. Look ma, no hands!
Cool, right? Of course, the modules are also computerized, and the whole system is networked together with a mother computer (the folks at the German industrial education firm Festo Didactic can tell you more about it — they sure gave us an earful!).
Now consider how much more computering and wireless communication goes on in late-model automobiles, and then there’s the whole “smart house” thing where all your lights and appliances are computered together with your car (see Ford for more on that), so now it’s really, really clear why we need wood computer chips.
More Than You Ever Really Wanted To Know About Wood Computer Chips
The University of Madison-Wisconsin (UW-Madison) has a plain English rundown of its wood computer chip study on its website, but since this is CleanTechnica, we went straight over to the journal Nature Communications, where we found the whole study with, amazingly, a long introduction in relatively plain English, under the title “High-performance green flexible electronics based on biodegradable cellulose nanofibril paper.”
The research team points out that, typically, the “active” region of a computer chip is relatively small, consisting of a thin layer at the top. More than 99% of a chip consists of a supportive layer, aka semiconductor materials. The equation is similar for microwave chips used in wireless functions.
So, the team focused on replacing the support layer with something biodegradable:
To minimize the usage of semiconductors, fully formed electronic devices can be fabricated on a sacrificial material in a dense array format, where each micro-scale device can be released and transfer printed onto any type of substrate, including biodegradable flexible substrates.
This is a lot trickier than they make out. Previous attempts at making biodegradable semiconductors involved silk and synthetic polymers as well as wood products, namely paper. However, the performance factor has been less than desirable, and some of the attempts tended to dissolve in water. Natural materials also tend to expand when exposed to moisture.
To resolve those problems, the UW-Madison team took wood down to the nanoscale — namely, cellulose nanofibril (CNF).
If that’s starting to sound like nanocellulose, run right out and buy yourself a cigar. The US Department of Agriculture has become a huge fan of nanoscale wood products and back in 2012 opened a $1.7 million production facility totally dedicated to forest nanoproducts. Here are the folks at the agency’s Forest Service Products Laboratory enthusing over the potentials (which explains why the lab is UW-Madison’s partner in the wood computer chip project, btw):
…nanocellulose-based materials can be stronger than Kevlar fiber and provide high strength properties with low weight. Applications for nanocellulose materials include use in lightweight armor and ballistic glass. Companies in the automotive, aerospace, electronics, consumer products, and medical device industries also see high potential for these innovative materials.
As described by the UW-Madison team, the transparency and flexibility of cellulose nanofibril (CNF) is complemented by “desirable electrical properties” that make it a good candidate for replacing conventional semiconductor materials.
A coating of epoxy helped to resolve the moisture problem, while also providing the chip with a smooth surface. The team also found that CNF is also better at resisting heat-induced expansion than its polymer counterparts.
While the electronic capabilities of CNF have been previously demonstrated, according to the UW-Madison team, this is the first demonstration that CNF can be used to make microwave chips for wireless devices.
In particular, this approach resolves the problems posed by gallium arsenide, which is commonly used in microwave chips for wireless devices. Gallium arsenide is notoriously difficult to separate and recover from e-waste.
And yes, the UWM study also found that the new wood chips are indeed biodegradable:
Fungal biodegradation of these CNF-based electronics, for the purpose of cycling degraded CNF back for forestry fertilizer, was also carried out to show the decaying process over time. While transfer printing techniques and CNF paper are used to realize various high-performance flexible electronics in this work, what is described is a new, much more sustainable, green electronic chip concept to address the societal impact of today’s economically important yet environmentally unsustainable consumer electronics, based on the important properties that were discovered from CNF.
Not for nothing, but not too long ago there was this painful episode in which Governor Walker tried to evaporate the famous Wisconsin Idea, described as “the guiding principle for the state’s universities for more than a century.” The Wisconsin Idea articulates a foundational mission to improve the lives of citizens beyond the classroom. Such as wood computer chips.
Okay, so. What now, Governor Walker?
Photo Credit: Yei Hwan Jung, Wisconsin Nano Engineering Device Laboratory/School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu