Graphene Prints More Smoothly Under The Influence Of Alcohol

August 22, 2020 by Kristina Panos 10 Comments

If you’ve ever sloshed coffee out of your mug and watched the tiny particles scurry to the edges of the puddle, then you’ve witnessed a genuine mystery of fluid mechanics called the coffee ring effect. The same phenomenon happens with spilled wine, and with functional inks like graphene.

Graphene and other 2D crystals print much better under the influence of alcohol.

The coffee ring effect makes it difficult to print graphene and similar materials onto silicon wafers, plastics, and other hard surfaces because of this drying problem. There are already a few commercial options that can be used to combat the coffee ring effect, but they’re all polymers and surfactants that negatively affect the electronic properties of graphene.

Recently, a group of researchers discovered that alcohol is the ideal solution. In the case of spilled graphene, the particles fleeing for the edges are naturally spherical. By adding a mixture of isopropyl and 2-butanol alcohol, they get flattened into a pancake shape, resulting in smoother deformation during the drying process and an easier printing process with better results.

Graphene is quite interesting by nature, and has many uses. It can shift from an insulator to a superconductor with the right temperature changes, and it can desalinate sea water for drinking.

Printing, Plating, And Baking Makes DIY Microlattices Possible

August 19, 2020 by Dan Maloney 15 Comments

To be honest, we originally considered throwing [Zachary Tong]’s experiments with ultralight metallic microlattices into the “Fail of the Week” bucket. But after watching the video below for a second time, it’s just not fair to call this a fail, so maybe we’ll come up with a new category — “Qualified Success of the Week”, perhaps?

[Zachary]’s foray into the strange world of microlattices began when he happened upon a 2011 paper on the subject in Science. By using a special photocurable resin, the researchers were able to use light shining through a mask with fine holes to create a plastic lattice, which was then plated with nickel using the electroless process, similar to the first half of the electroless nickel immersion gold (ENIG) process used for PCBs. After removing the resin with a concentrated base solution, the resulting microlattice is strong, stiff, and incredibly light.

Lacking access to the advanced materials and methods originally used, [Zachary] did the best he could with what he had. An SLA printer with off-the-shelf resin was used to print the skeleton using the same algorithms used in the original paper. Those actually turned out pretty decent, but rather than electroless plating, he had to go with standard electroplating after a coat of graphite paint. The plated skeletons looked great — until he tried to dissolve the resin. When chemical approaches failed, into the oven went the plated prints. Sadly, it turns out that the polymers in the resin expand when heated, which blew the plating apart. A skeleton in PLA printed on an FDM printer fared little better; when heated to drive out the plastic, it became clear that the tortuous interior of the lattice didn’t plate very well.

From aerogels to graphene, we love these DIY explorations of new and exotic materials, so hats off to [Zachary] for giving it a try in the first place.

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Modified Bricks Can House Energy, Too

August 16, 2020 by Kristina Panos 43 Comments

What if building an emergency battery were as easy as painting conductive plastic onto bricks, stacking them, and charging them up? Researchers at Washington University in St. Louis have done just that — they’ve created supercapacitors by modifying regular old red bricks from various big-box hardware stores.

The bricks are coated in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), a conductive polymer that soaks readily into the bricks’ porous surface. When the coated brick is connected to a power source such as a solar panel, the polymer soaks up ions like a sponge. PEDOT:PSS reacts with the iron oxide in the bricks, the rust that gives them their reddish-orange color. Check out the demonstration after the break — it’s a time lapse that shows three PEDOT-coated bricks powering a white LED for ten minutes.

We envision a future where a brick house could double as a battery backup when the power goes out. The researchers thought of that too, or at least had their eye on the outdoors. They waterproofed the PEDOT-coated bricks in epoxy and found they retain 90% of their capacitance and are still efficient after 10,000 charge-discharge cycles. Since this doesn’t take any special kind of brick, it seems to us that any sufficiently porous material would work as long as iron oxide is also present for the reaction. What do you think?

If you can get your hands on the stuff, PEDOT:PSS has all kinds of uses from paper-thin conductors to homebrew organic LEDs.

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[NileRed] Makes Superconductors

August 4, 2020 by Al Williams 8 Comments

We always enjoy [NileRed’s] videos. His latest shows how he made some relatively high-temperature superconducting ceramic. After finding what appeared to be some really good instructions on the Internet, [NileRed] found there were some things in the paper that didn’t make sense. You can watch the video, below.

The superconductor was YBCO, sometimes known as 123 because of the ratio of its components. Turns out that most of the materials were available online, except for one exotic chemical that he had to buy from a more conventional source.

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No-Melt Nuclear ‘Power Balls’ Might Win A Few Hearts And Minds

July 30, 2020 by Kristina Panos 137 Comments

A nuclear power plant is large and complex, and one of the biggest reasons is safety. Splitting radioactive atoms is inherently dangerous, but the energy unleashed by the chain reaction that ensues is the entire point. It’s a delicate balance to stay in the sweet spot, and it requires constant attention to the core temperature, or else the reactor could go into meltdown.

Today, nuclear fission is largely produced with fuel rods, which are skinny zirconium tubes packed with uranium pellets. The fission rate is kept in check with control rods, which are made of various elements like boron and cadmium that can absorb a lot of excess neutrons. Control rods calm the furious fission boil down to a sensible simmer, and can be recycled until they either wear out mechanically or become saturated with neutrons.

Nuclear power plants tend to have large footprints because of all the safety measures that are designed to prevent meltdowns. If there was a fuel that could withstand enough heat to make meltdowns physically impossible, then there would be no need for reactors to be buffered by millions of dollars in containment equipment. Stripped of these redundant, space-hogging safety measures, the nuclear process could be shrunk down quite a bit. Continue reading “No-Melt Nuclear ‘Power Balls’ Might Win A Few Hearts And Minds” →

Aluminium Pucks Fuel Hydrogen Trucks

May 26, 2020 by Kristina Panos 147 Comments

In the race toward a future free from fossil fuels, hydrogen is rapidly gaining ground. On paper, hydrogen sounds fantastic — it’s clean-burning with zero emissions, the refuel time is much faster than electric, and hydrogen-fueled vehicles can go longer distances between refuels than their outlet-dependent brethren.

The reality is that hydrogen vehicles usually need fuel cells to convert hydrogen and oxygen into electricity. They also need pressurized tanks to store the gases and pumps for refueling, all of which adds weight, takes up space, and increases the explosive potential of the system.

Kurt Koehler has a better idea: make the hydrogen on demand, in the vehicle, using a solid catalyst and a simple chemical reaction. Koehler is the founder of Indiana-based startup AlGalCo — Aluminium Gallium Company. After fourteen years of R&D and five iterations of his system, the idea is really starting to float. Beginning this summer, these pucks are going to power a few trucks in a town just outside of Indianapolis.

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Dyeing Fabric To Create Sensors

May 22, 2020 by Danie Conradie 21 Comments

Fabrics with electrical functionality have been around for several years, but are very rarely used in mainstream clothing. The fabrics are very expensive and the supply can be unreliable. Frustrated by this, [Counter Chemists] developed PolySense, simple open-source technology to make any fibrous material into a conductive material that can be used to sense pressure, stretch, capacitive touch, humidity, or temperature.

PolySense uses a process called in-situ polymerization, effectively dying a fabric to become piezoelectric. This is done by first soaking the fabric in a mixture of water and the organic compound pyrrole, and then adding iron chloride to trigger a reaction. The polymerization process that takes place wraps the individual fibers of the fabric in conductive polymer chains.

Instead of just uniformly coating a fabric, various masking techniques can be used to dye patterns onto the fabric for various use cases. The video after the break shows a range of these applications, including using polymerized gloves and leggings for motion capture, a zipper that acts like a linear potentiometer, and touch-sensitive fabric. The project page lists sources for the required chemicals in both Europe and the US, and we look forward to seeing what other applications the community can come up with.

The project is very well documented, with a number of scientific papers covering all the details. [Counter Chemists] will also be presenting PolySense at the 2020 Virtual Maker Faire.

This technology can also be used to make a fabric piano with a lot less effort. On the more mechanical side of things, you can also 3D print on pre-stretched fabric to make it pop into 3D shapes.

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