Leeds University researchers have discovered a new non-porous material that becomes molecularly thicker when stretched.
A world’s first, the synthetic material has unique and inherent auxetic stretching properties.
This implies that when stretched, the material becomes thicker perpendicular to the applied force.
There are many materials in nature that exhibit auxetic capabilities. Some notable examples are cat skin, the protective layer in mussel shells, and tendons in the human body.
Scientists have been trying to create synthetic auxetic materials for more than 30 years, but it was only recently that they were able to make them by structuring conventional materials using complex engineering processes.
Nevertheless, these processes are overtly time consuming, costly, and can lead to weaker, porous products.
The Leeds study led by Dr Devesh Mistr has now identified a synthetic molecular version of the process, helping usher in products with a wide range of applications.
“This new synthetic material is inherently auxetic on the molecular level and is therefore much simpler to fabricate and avoids the problems usually found with engineered products,” says Mistr, “But more research is needed to understand exactly how they can be used.”
“When we stretch conventional materials, such as steel bars and rubber bands they become thinner. Auxetic materials on the other hand get thicker.”
“Auxetics are also great at energy absorption and resisting fracture. There may be many potential applications for materials with these properties including body armor, architecture and medical equipment.”
The team discovered the yet-to-be-named material while examining the capabilities of Liquid Crystal Elastomers.
Liquid crystals are best known for their use in mobile phone and television screens and have both liquid and solid properties.
When they are linked with polymer chains to form rubbery networks, they have completely new properties and possible applications.
“Our results demonstrate a new use for liquid crystals beyond the flat screen monitors and televisions many of us are familiar with,” said Professor Helen Gleeson, study co-author and Head of Physics and Astronomy at Leeds.
Image and content: Devesh Mistry/University of Leeds