Altering the very fabric of technophilic society, a multinational team of material scientists have created electric circuits and transistors out of cotton fibers. Two kinds of transistor were created: a field-effect transistor (FET), much like the transistors found in your computer’s CPU; and an electrochemical transistor, which is similar but capable of switching at lower voltages, and thus better suited for wearable computers.
If you’re like me, you’re probably thinking that cotton is a very strong insulator and not at all conducive to conductiveness — but before you accuse this team from Italy, France, and the United States of witchcraft and wizardry, bear in mind that they kind of cheated. Cotton is just the substrate: To make it conductive, the researchers coated cotton threads in a variety of other materials. To make conductive “wires,” the team coated the threads with gold nanoparticles, and then a conductive polymer. To turn a cotton wire into a semiconductor, it was dipped in another polymer, and then a further glycol coating to make it waterproof.
The end result, according to the research paper, is cotton yarns that can be used to fashion the basic building blocks of a computer circuit, but still retain their flexibility. Because of the coatings the threads are slightly stiffer, but on the flip side they are more elastic, too. It is not a time-consuming process to create these conductive cotton threads, either: It’s comparable to dyeing.
These tailor-made cotton circuits will weave the way to, quite literally, wearable computers. For the first time, instead of incorporating small chips or flexible printed circuits, you will be able to build a t-shirt that is also a computer. Just think how many interconnections there are in a standard cotton shirt — it’s on the scale of hundreds of thousands or millions — and each one could become a transistor. We’re obviously a little way away from that reality, but the idea of incorporating sensors — radiation detectors, toxic substance detectors, heart beat monitors — is just around the corner.
Imagine the high-tech grandmother of tomorrow, too: Instead of knitting you a crappy Christmas sweater, she could knit a sweater with a built-in GPS unit, and love-handle sensors that alert her when your body-mass index reaches dangerously low levels.
I wonder if overclocking a CPU built from this could make it burst into flame.