Graphene Overcomes Achilles' Heel of Artificial Muscles

Researchers aim to create a biomimetic robot

2 min read
Graphene Overcomes Achilles' Heel of Artificial Muscles
Illustration: Korea Advanced Institute of Science and Technology

In the world of biomimetic robotics, so-called artificial muscles have promised everything from the ability to make fish-like fins for underwater vehicles to devices to help the disabled in their rehabilitation.

These ionic polymer composites are attractive for their sheer simplicity. You just put two electrodes on the polymer and when you switch on the voltage, the ions migrate, deforming the polymer.

However, there was a problem with the metal electrodes. After being exposed to air and current, the electrodes would begin to crack, leaking ions and diminishing the muscle’s performance.

Scientists at the Korea Advanced Institute of Science and Technology (KAIST) have come up with a solution to that problem, and it involves graphene.

In research published in the journal ACS Nano, the KAIST team made the electrodes from a cost-effective version of graphene called hydrophobic laser-scribed reduced graphene oxide paper (HLrGOP).

We have recently seen laser-scribed graphene finding applications in supercapacitors. And reduced graphene oxide, which refers to it being reduced back towards pure graphene (minus the oxide), has been the basis for enabling experimental 3-D holographic displays.

Nonetheless, it is the hydrophobic properties of this form of graphene that is the key to making it effective in this application. The graphene electrodes have a smooth outer surface that repels water and resists cracking. While the outer surface is smooth, the inner surface is rough, and that helps in the transport of ions within the polymer membrane.

In their experiments with the new version of the artificial muscle, the researchers recorded much improved durability and a lack of performance degradation.

While these results are encouraging to the researchers, they concede that more work needs to be done to improve the graphene-based electrodes.

The KAIST team will also be aiming to develop a biomimetic robot that employs the improved artificial muscles. The robot they are planning will be able to walk on water like a water strider, or gerridae.

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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.

Avicena

If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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