For a long time, scientists have been working to make materials that are stronger and stiffer.
This is especially true in the world of metamaterials—synthetic materials with tiny, carefully designed structures that give them amazing properties.
But there’s always been a trade-off: the stiffer the material, the less flexible it becomes.
That’s a problem when you want something that’s both strong and able to bend or stretch—like a fabric that won’t tear or a medical device that can move with the body.
Now, engineers at MIT have developed a new kind of metamaterial that is both strong and remarkably flexible.
Even though they used a stiff, plastic-like material—similar to plexiglass—they printed it in a very special structure that gives it the ability to stretch over four times its original length without breaking.
That’s something the raw material can’t do on its own.
This breakthrough, published in Nature Materials, is based on something called a “double-network” design.
The idea was inspired by hydrogels—soft, stretchy materials like Jell-O that are made mostly of water.
Scientists have found that combining two different types of polymer networks in hydrogels can make them soft yet strong. The MIT team wondered if a similar strategy could work for harder materials.
Their solution was to print two microscopic patterns into the material at once. The first is a strong, rigid structure made of grid-like struts. The second is a soft, springy weave that wraps around the rigid parts.
Together, they act like a safety net. When the rigid parts start to crack under stress, the softer weave picks up the slack. This stops the cracks from spreading and helps the whole structure stay together.
The result is a material that can stretch three times its length—10 times more than a typical version of the same plastic.
Even more surprising, when the researchers added tiny holes or “defects” to the material, it became even more flexible and could absorb more energy. This is the opposite of what you’d expect, but it works because the holes help spread out stress and prevent tearing.
The MIT team hopes their new design could be used to create stronger, tear-proof fabrics, flexible electronics, and even medical scaffolds to help grow new tissues. They also plan to experiment with making these materials out of different substances—maybe even ones that respond to heat or electricity.
That way, we could one day have smart materials that adjust to their environment, staying firm in the cold and softening when it’s warm.
