That Material is so Meta

I don’t like the idea of writing another negative post so soon, but this article just doesn’t seem right.

The idea here is that metamaterials, materials engineered to have specific optical properties, can be used to create a means of sticking two surfaces together. This is currently being researched by John Zhang ‘and buddies’ at the University of Southampton. According to one article, it is very similar to the way a gecko can climb on walls.

The explanation is that the metamaterial can stick to surfaces by using a specific type of force, the radiation pressure of light on surfaces. Light’s radiation pressure is a simple result of the photon side of its nature. It collides with a surface, imparting an absurdly small force on the surface. This force is nowhere near enough to mean anything in pretty much any situation.

Apparently through the use of resonance, it is possible not only to reverse the direction of the force, so that it pulls towards the surface instead of a push away, but it is also possible to make it strong enough to resist gravity. Of course, the amount of force needed to fight gravity changes based on how much is being carried. It might be enough for a needle-less push-pin, but not enough for a small robot. (Though I doubt it’d carry much of anything, especially when they say it needs borderline no energy to operate.)

My other main wonder is what geckos have to do with this in the first place. They certainly are cool, and can climb upside-down in a manner similar to what is being suggested here, but so can ants, and they aren’t getting any attention. The actual researchers don’t make any mention of them in the original article. The PopSci article, however, implies that they are actually the same type of force. Geckos cling to stuff via the use of a number of tiny hairs, or cilia, on their feet, not light energy. That would be downright inconvenient, seeing as geckos are commonly nocturnal.

Lastly, but easily most importantly, it seems that Zhang is coming out with this a bit too early. At the moment, they are relying purely on theory and speculation. They have yet to find any proof of their ideas. He expects this to be ‘easy to detect’ though. That phrasing kind of reminds me of this.

In a related (to the linked comic) note, it’s likely that the discrepancies in these articles are more a product of the article than the actual research. It could just be a strong case of this.