Ancient Islamic Art Inspires Metamaterials — Intricate, Repeating Patterns Help Design Stretchy, Switchable Materials

Islamic art has helped in the creation of metamaterials. The extensively intricate and repeating patterns found in the Islamic architecture have assisted scientists to create a new breed of materials that widen when stretched, instead of getting thinner. The metamaterials have next generation application in medical devices and satellites.

Metamaterials aren’t found in nature. These materials have to be specially fabricated. While there are several iterations being developed, a Canadian team chose to model theirs on ancient Islamic art, commonly observed in the houses and religious places of Muslims across the world. Replicating these complex patterns on rubber sheets have allowed the team to impart some wondrous properties that defy logic and general convention associated with flexible fabrics.

Naturally occurring materials, like cotton and rubber, as well as artificially created materials like plastics, follow a particular pattern when stretched. While stretching longer in the direction they are pulled, majority of these materials shrink in the lateral direction. In other words, in order to get larger in the direction of tension, the material gets thinner in the other. This happens because the strands and patterns in the material are getting reoriented in the direction they are getting pulled. However, metamaterials display a completely different behavior that appears to bend the laws of physics, shared Dr. Ahmad Rafsanjani, from McGill University in Montreal,

“In conventional materials, when you pull in one direction it will contract in other directions. But with ‘auxetic’ materials, due to their internal architecture, when you pull in one direction they expand in the lateral direction.”

Metamaterials grow wider when stretched. In other words, these materials will grow larger in shape when stretched in one direction, instead of just longer and thinner. The Canadian team chose rubber as their choice of material since it is easily stretchable. Moreover, these perforated rubber sheets remain stable in their expanded state until they are squeezed back again, reported BBC.

Their unique property is derived from their geometric substructure, reported New Scientist. When not stretched, the pattern on the sheet appears to be a series of connected squares. The design of the squares, inspired from Islamic art, causes them to turn in a pattern that’s interdependent. The relative motion of the squares doesn’t impact the density of the product, which follows the law of stretching and lowers when pulled. However, the squares allow the sheet to grow in thickness. Cumulatively, the design causes the sheet to grow when stretched.

Dr. Rafsanjani shared that his search for new designs to create such “auxeticity” ended when he came across intricately carved stonework of two 1,000-year-old tomb towers in Iran,

“When you look at Islamic motifs, there is a huge library of geometries. On the walls of these two towers, you can find about 70 different architectures: tessellations and curlicue patterns.”

Two of these patterns offered the scientist a new way to construct materials that were endowed with an unusual combination of properties. When recreated in a simplified form using modern manufacturing techniques involving a laser cutter, the sheets displayed these amazing properties which were never witnessed earlier. Not only were these sheets auxetic – expanding in all directions when stretched – but they could also snap easily back and forth between stretched and unstretched states, reported Click Ittefaq.

There have been attempts in the past to create such materials. Majority of the designs were based on the ancient origami art, which involves creating patterns by folding a piece of paper in multiple directions, without cutting it. However, these new designs are far simpler to construct, shared Dr. Rafsanjani,

“These designs are easier to fabricate; all you need is a laser cutter. Depending on the resolution of the laser you could downscale your samples, probably to the micro scale. Or you could upscale it for larger components like satellites or solar panels.”

Not only are the possibilities endless for creating the metamaterials based on Islamic art, but their applications are limitless too, shared the researchers.

[Photo by Sean Gallup/Getty Images]