Now You Feel It, Now You Don't: Nanomaterial Cloaks the Sense of Touch

This image shows how the metamaterial displaces pressure around an object.

Image: Karlsruhe Institute of Technology (KIT)

A real invisibility cloak may still be the stuff of fantasy, but scientists have figured out a way to hide objects from touch.

Two years ago, researchers at the Karlsruhe Institute of Technology (KIT) in Germany successfully created pentamodes, or mechanical metamaterials. Now, researchers have found a fascinating property in the metamaterial: the ability to hide or “cloak” the existence of foreign objects hidden within it. It’s a discovery that could lead to making everything from more comfortable camping gear to shoes that make you feel like you’re walking on air.

Built at a millimeter scale, this polymer-based, scaffold-like structure can shape itself around a object â€" say, a tiny hard tube â€" and disperse pressure in such a way that human touch can't detect its existence. Put another way, if all the mattresses from the Hans Christen Anderson classic fable The Princess and the Pea were made out of this mechanical metamaterial, the princess would never have felt the pea, even if she were sleeping on just one thin sheet of the nanomaterial.

This is how Karlsruhe Institute of Technology's (KIT) metamaterial works.

This trick wouldn’t work in an everyday material. The KIT researchers describe its mechanical metamaterial as such:

[It] is a crystalline material structured with sub-micrometer accuracy. It consists of needle-shaped cones, whose tips meet. The size of the contact points is calculated precisely to reach the mechanical properties desired. In this way, a structure results, through which a finger or a measurement instrument cannot feel its way.

This mechanical metamaterial is quite pleasing to the eye, and thanks to its nano design, is also incredibly light. Its unique structure is produced by using Nanoscribe’s 3D laser lithography.

While this is purely a research project, the results of which are published in the Nature Communications journal, the KIT researchers do envision an interesting nanomaterial future. The discovery could, for example, eventually be used to make more comfortable sleeping bags that shield the user from feeling rocks or pebbles on the ground or rugs that hide the bumps of bad flooring and cables.

There's no word yet if this nanomaterial could someday be used for more nefarious purposes, like hiding a weapon or contraband from a pat-down.

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