Thin and flexible but tough protection

Dr Dan Plant, then an engineering PhD student at Imperial College London, had the idea for Armourgel when he was racing motorbikes in Europe; it was far too hot for traditional motorcycling protective clothing and he needed a solution.

He began working on a new protective material by testing combinations and layers of different composites and using softer, more flexible resins, instead of the hard resins covered in multiple textile layers that protective clothing is traditionally made from. His team tested around 2,500 different compositions before finding the optimum combination that resulted in a light, thin, yet protective material, made from a synergy of a thickening polymer and an auxetic geometry.

This resulted in a material that combines the properties of a smart material with a clever internal geometry. The smart material, shear-thickening polymer, is soft and flexible, but absorbs shock and stiffens momentarily on impact. The material has a different response at different strain rates. When moved slowly it is soft and flexible, allowing it to move with the musculature of the body, but when it is subjected to impact it momentarily stiffens, absorbing energy and spreading the load.

The technology was first used in clothing for extreme sportswear. Dr Plant applied for and was awarded a Royal Academy of Engineering Enterprise Fellowship, which provided him with funding and mentoring from an engineering leader to help him develop and commercialise Armourgel for the medical market. The first development he focused on was a preventative measure for hip fractures after learning that these injuries account for 15% of orthopaedic hospital beds, costing the NHS £2.4 billion a year.

In order to use the technology to create a preventative device for hip fractures, the team needed to design something that could provide the necessary protection, but was also comfortable enough to be worn on a daily basis under regular clothing. As Armourgel has high energy-absorption levels, it can be used in a much thinner layer and integrated within garments.

As the company continues to expand into new markets and applications, the technology will be used in helmets for use in areas such as the military, racing and sports. Dr Plant hopes to produce Armourgel products to sell directly to consumers and set up an advanced manufacturing centre in the UK.

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This article has been adapted from "Thin and flexible but tough protection", which originally appeared in the print edition of Ingenia 70 (March 2017).