A research collaboration between the California Institute of Technology and Singapore's Nanyang Technological University has yielded "structured fabrics with tunable mechanical properties." What that boils down to is a material that can be as flexible and wearable as fabric, yet which can go rigid when a particular force is applied to it. (One obvious application would be a cast on a broken limb, for instance.)

The researchers were inspired by medieval chain mail armor and…coffee beans. CalTech researcher Chiara Daraio observes that loose coffee beans can be poured, like liquid. But when they arrive in vacuum-formed packaging, where the beans are jammed together, they form a rigid surface.

The team thus designed an interlocking shape that, when spaced out from its neighbors, minimizes surface area contact; but when compressed against its neighbors, maximizes contact.

In these early stages of the research, the team vacuum-seals the matrix of shapes in order to make them rigid. Obviously vacuum-sealing is not practical for say, architectural applications, but the team theorizes the same drawing-together trick might be achieved through tunable magnetic attraction, or "tension created by fibers or pulleys that could be interwoven in the hollow space between particles," Daraio says.

Here's a closer look:

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