A simple bundle of office staples can teach us something surprising about the future of materials.
When tightly packed together, staples can lock into each other and become very hard to pull apart.
But with the right movement or vibration, they can quickly fall loose again. Inspired by this behavior, researchers are now designing a new type of material that can be both strong and flexible at the same time.
A team at the University of Colorado Boulder has been studying how particles that interlock, like staples, can create materials with unusual and useful properties.
Their work, published in the Journal of Applied Physics, explores how changing the shape of tiny particles can dramatically change how they behave when grouped together.
The key idea behind the research is something called “entanglement.” This happens when particles become intertwined, forming a network that holds together. Similar patterns can be found in nature.
For example, bird nests are made from interwoven sticks, and bones combine hard minerals with softer materials to create strength. Scientists want to copy these natural designs in human-made materials.
The researchers discovered that shape plays a critical role. Smooth particles, like grains of sand, do not easily lock together because they are rounded. But when particles are designed with hooks or legs—similar to the shape of a staple—they can grab onto each other and form strong connections.
To find the best design, the team used computer simulations to test different shapes and predict how well they would interlock. After identifying promising designs, they created real samples and tested how they behaved. They found that a simple two-legged shape, much like a staple, worked especially well.
What makes these materials exciting is their unique combination of strength and toughness. Most materials are either strong or tough, but not both. These entangled particles can resist being pulled apart while also absorbing energy without breaking easily.
Another unusual feature is how easily the material can change. By applying vibrations, the researchers can control how tightly the particles are connected. Gentle vibrations can make the material lock together and become stronger, while stronger vibrations can cause it to fall apart. This means the material can switch between a solid-like state and a loose, flowing state.
This behavior makes the material hard to classify. It is not quite a solid, but it is not a liquid either. This opens up new possibilities for engineering and design.
One potential use is in sustainable construction. Buildings or bridges could be made from these materials and later taken apart and reused, reducing waste. Another idea is in robotics. Small robots could connect together to form larger structures, complete tasks, and then separate again.
The researchers are now experimenting with even more complex shapes, including particles with extra “legs” similar to plant burrs that stick to clothing. These designs could create even stronger connections.
While the technology is still in its early stages, it shows how simple ideas—like a handful of staples—can lead to entirely new ways of building materials for the future.
