Huge amounts of e-waste are thrown away every day since they are becoming outdated at an increasingly fast pace.
That’s why scientists from the University of Wisconsin-Madison have started producing “wooden” semiconductor chips that could almost entirely biodegrade once left in a landfill. As an added bonus, the chips are also flexible, making them prime candidates for use in flexible electronics.
The substrate of the UW-Madison chips is actually made of a translucent material known as Cellulose NanoFibrils (CNF) – it’s also called nanofibrillated cellulose.
The material is typically made by adding water to cellulose-containing materials (usually wood waste, as would be found at paper or lumber mills) then using high-pressure homogenizers, grinders or microfluidizers to rip the wood fibers into much smaller cellulose nanofibers. This results in a gel which is subsequently freeze-dried to remove the water, leaving the long, interconnected nanofibers behind.
Working with the US Department of Agriculture’s Forest Products Library, the researchers added an epoxy coating to the CNF. This made the substrate smooth enough for application of the non-CNF circuitry, plus it kept the material from expanding or contracting by taking on or releasing moisture.
Traditional chips use petroleum-based polymers for their substrates, which are non-biodegradable, require the use of non-renewable resources, contain toxic compounds, and aren’t flexible.
Article cover photo:
“Still from YouTube video published by Wall Street Journal”