Your future windows, walls, and possibly boats will be made of ants — or at least of an ant-like substance. New research shows why ants classify as both a solid and a liquid, and why they’d make the best self-repairing building material.


The fire ants in the picture above are in a rheometer, a device that is usually used when testing hand creams or toothpaste for consistency by rotating, not by squishing. While the ants tend to resist the flow of the material, sooner or later the force gets to be too much for them. At that point they “play dead,” and their response to being stirred around is no different from that of dead ants. They go with the flow until the pressure is off. On the other hand, if you compress them quickly—as the scientists do with the ball of ants in the picture below—they can link up again quickly and spring back into shape.


This gives them the properties of a viscoelastic material—a substance that resists any deformation, that can flow when it needs to, but that springs back into shape after it has been deformed. That is a very valuable property. If it could be harnessed, it would mean that instead of shattering, materials like windows or walls could flow back into shape if they were deformed by too much stress. Take a look at what happens when a group of ants gets a penny dropped onto it:

The ants aren’t being crushed. (Other than that one at the very top left.) Instead, they’re moving aside just before they get injured, letting the penny drop slowly.



This doesn’t happen all the time. Ants with lots of space just move aside. However, the more ants get together, the more they act like an elastic fluid instead of individual creatures.

We’re a long way from constructing materials like these, but at least by observing ants, we can get a clue as to how we might do so someday. If we can build a million tiny robots and give them each the basic instructions that will allow them to behave like crowded ants, we might make walls that fix themselves.


[Source: Mechanics of Fire Ant Aggregations]