The Coming Copper Shortage: Aluminium Or Carbon Nanotubes To The Rescue?

The use of aluminium in wiring is unlikely to bring a smile to the face of anyone who has had to deal with it in a 1960s, or early 1970s-era house. The causes behind the fires and other accidents were myriad, including failure to deal with the higher thermal expansion of aluminium, the electrically insulating nature of aluminium oxide, and the general brittleness of aluminium when twisted.

Yet while copper is superior to aluminium in terms of electrical conductivity and ease of installation, copper prices have skyrocketed since the 1970s, and are on the verge of taking off to the moon. A big part of the reason is the increased use of copper in everything from electronics and electrical motors to generators, driven by large-scale deployment of wind turbines and electrical vehicles.

As the world moves to massively expand the use of electrical cars and installation of wind turbines, copper demand is predicted to outstrip current copper supply. With aluminium likely to make a big return as a result, it’s worth taking a look at modern-day aluminium-based wiring, including copper-clad aluminium and the use of carbon-based replacements. Continue reading “The Coming Copper Shortage: Aluminium Or Carbon Nanotubes To The Rescue?”

A shirt with carbon nanotube threads stitched into a shirt monitor the wearer's heart rate.

Sew-able Carbon Nanotube Thread Could Spin A Lot Of Awesome

Plenty of people just plain dislike wearing jewelry, even (or especially) smart watches. Nevertheless, they’d like to have biofeedback like everybody else. Well, we watch-less ones have something to look forward to, because a group of graduate students at Rice University have created extremely strong conductive thread woven from carbon nanotubes, which can be sewn into standard athletic clothing and used as electrodes, antennas, or simply as ballistic protection.

At 22 microns wide, the original carbon nanotubes were too skinny to use as thread. Instead, the team braided together three bundles of seven ‘tubes each using the type of machine that model boat builders use to make tiny rigging. Then they zig-zag stitched the threads into a shirt, which gives the stitches added flexibility. This thread maybe as strong and conductive as metal, but the fibers are soft and flexible, and most importantly, machine-washable. Between its strength and conductivity, this thread could have a long list of applications from military down to civilian. Check out the introduction in the video after the break.

For now, the shirt has to be pretty snug, but future garments could easily have higher concentrations of nano-threads in order to get a better signal. Good thing, because we’re still carrying around our COVID nineteen — aka the weight we’ve gained since the longest March of anyone’s life, and never liked tight shirts anyway.

What else can carbon nanotubes do? Plenty, like keep 3D prints from delaminating.

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3D Printed Transistor Goes Green

We’ll be honest, we were more excited by Duke University’s announcement that they’d used carbon-based inks to 3D print a transistor than we were by their assertion that it was recyclable. Not that recyclability is a bad thing, of course. But we would imagine that any carbon ink on a paper-like substrate will fit in the same category. In this case, the team developed an ink from wood called nanocelluose.

As a material, nanocellulose is nothing new. The breakthrough was preparing it in an ink formulation. The researchers developed a method for suspending crystals of nanocellulose that can work as an insulator in the printed transistors. Using the three inks at room temperature, an inkjet-like printer can produce transistors that were functioning six months after printing.

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The Current State Of The Black Market: You Can’t Buy Vantablack

Sometimes you need something to be utterly, totally, irredeemably black. Not just a little bit black, not just really really really dark blue, but as black as it is possible to get. It might be to trap light in a camera or a telescope, for artistic purposes, or even to make your warplane a more difficult target for enemy missiles. Either way, we’re here to help, not to judge. So what are your options?

Well, first of all, there’s the much-lauded Vantablack. The name itself is a clue as to its origin – Vertically Aligned Nano Tube Arrays. It works by coating an object with a forest of carbon nanotubes in a complicated vacuum deposition process. When light hits the surface, some of it is absorbed by the nanotubes, and any that is reflected tends to be absorbed by neighbouring nanotubes rather than escaping the surface coating of the object.

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Using Nanotubes To Strengthen 3D Prints

3D printing has brought the production of plastic parts to the desktops and workshops of makers the world over, primarily through the use of FDM technology. The problem this method is that when squirting layers of hot plastic out to create a part, the subsequent vertical layers don’t adhere particularly well to each other, leading to poor strength and delamination problems. However, carbon nanotubes may hold some promise in solving this issue.

A useful property of carbon nanotubes is that they can be heated with microwave energy. Taking advantage of this, researchers coated PLA filament in a polymer film containing carbon nanotubes. As the layers of the print are laid down, the nanotubes are primarily located at the interface between the vertical layers. By using microwaves to heat the nanotubes, this allows the print to be locally heated at the interface between layers, essentially welding the layers together. As far as results are concerned, the team reports an impressive 275% improvement in fracture strength over traditionally printed parts.

The research paper is freely available, which we always like to see. There’s other methods to improve your print strength, too – you could always try annealing your printed parts.

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Honey, They Shrunk The Transistor

Silicon transistors keep shrinking (current state of the art is about 20 nanometers). However–in theory–once the gate goes to 5 nanometers, the electrons tunnel through the channel making it impossible to turn the transistor off. Berkeley researchers have used a different material to produce a transistor with a 1-nanometer gate. For point of reference, a human hair is about 50,000 nanometers thick.

The secret is to switch away from silicon in favor of another semiconductor. The team’s choice? Molybdenum disulfide. Never heard of it? You can buy it at any auto parts store since it is a common lubricant. Electrons have more effective mass as they travel through molybdenum disulfide than silicon. For a larger transistor, that’s not a good thing, but for a small transistor, it prevents the electron tunneling problem.

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Hackaday Prize Entry: Open Source Electrospinning Machine

Electrospinning is a fascinating process where a high voltage potential is applied between a conductive emitter nozzle and a collector screen. A polymer solution is then slowly dispensed from the nozzle. The repulsion of negative charges in the solution forces fine fibers emanate from the liquid. Those fibers are then rapidly accelerated towards the collector screen by the electric field while being stretched and thinned down to a few hundred nanometers in diameter. The large surface area of the fine fibers lets them dry during their flight towards the collector screen, where they build up to a fine, fabric-like material. We’ve noticed that electrospinning is hoped to enable fully automated manufacturing of wearable textiles in the future.

[Douglas Miller] already has experience cooking up small batches of microscopic fibers. He’s already made carbon nanotubes in his microwave. The next step is turning those nanotubes into materials and fabrics in a low-cost, open source electrospinning machine, his entry for the Hackaday Prize.

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