The future belongs to wearables – small networked computers that are tucked into clothing or worn on the body. A new skin-like, synthetic material could advance the technology or even be used as artificial skin for robots.
One wipe along the jacket sleeve switches the living room light off; a tap of the hand on the coat collar places a phone call to the boss: what sounds like science fiction has long since arrived in science and also in the clothing industry. There is hardly a topic that captures people’s imagination more than small networked computers, so-called wearables, which are worn on the body or integrated into clothing.
This wearable technology is already being used today, especially in sports: smartwatches and fitness bracelets measure pulse, heart rate and breathing rate. Smart shirts monitor sleep or help to perform movements correctly during yoga and Pilates. Such tops are equipped with sensors that detect body posture and muscle activity and indicate incorrect movements by applying light pressure to the respective area. There are now even fitness suits that train the muscles without you having to move yourself. Tiny electrodes are inserted into these to stimulate the muscles from the outside.
However, wearables are also taking over other areas: diabetic patients can use them to measure their blood sugar levels, data glasses project images directly onto the retina, and wearables in nappies track the sleep stages of babies. It is not just about technical challenges, such as the development of tiny sensors, but also about the conductive material. It must be robust and, at the same time, durable and stretchy – and of course comfortable to wear. “A second skin, so to speak,” explains Dr. Baohu Wu. At the Jülich Centre for Neutron Science (JCNS) at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, the physicist and instrument scientist is working on materials, including for wearables.
He draws his inspiration from nature: from biological materials that conduct ions – in this case, electrically charged macromolecules. To understand the details of the relationship between the structure of these materials and their properties, he relies on neutron and X-ray scattering methods. With the help of these methods, Wu, together with researchers from the Chinese Donghua University in Shanghai, has successfully developed a skin-like, synthetic material that meets all the requirements for materials for wearables. Smart clothing could also benefit. “Even artificial skin for robots is conceivable,” explains Wu. Due to the special properties of the material, robots could feel their environment in greater detail and more sensitively than before – that is, they could become more human.
The material is a so-called elastomer: a plastic that can be easily stretched without tearing. “Far better than previous materials, our elastomer replicates both the elasticity of our skin and its ability to become more stable when reshaped. Our plastic even has skin-like self-healing powers, so that it can repair damage itself and restore functionality,” Wu explains. Until now, it had barely been possible to produce these properties in a single material.
Wu and his colleagues had a trick: for their material, they combined two dynamic polymer networks that interact with each other and optimally complement each other in their properties. One polymer network dissolves chemical bonds quickly, meaning that a material made of it can be stretched well, but it tears or wears out very quickly.0
is the stretchability of the new elastomer. This means it can be stretched to its 16-fold size. For comparison: a balloon can be inflated to about 7 times its size.
Stretchy and tearproof
The chemical bonds in the other network, by contrast, remain stable. A material made of it does not tear, but would be rather stiff and hardly ductile. Thanks to the combination of the two, the new material can be stretched extremely well without tearing and then quickly slips back into its original shape. “Simply put: it fits like a second skin. According to our preliminary findings, it would be possible, for example, to wear portable devices such as electrocardiographs on the body like a second skin,” says the Jülich researcher.
What’s more, “The properties of our elastomer can increase the lifespan of wearables’ materials, reduce replacement costs, decrease the degradation-related inefficiency of these materials and improve product safety,” Wu concludes. By determining the interrelations between the structures and the sought-after properties, he made a decisive contribution, enabling his colleagues to develop the promising materials in a targeted manner.
Wu hopes that the new material will advance research. He firmly believes in the future of wearables: “They will continuously gain importance. Many other applications are conceivable if we succeed in developing even smaller and more powerful sensors and more durable devices that feel pleasant on the skin as well,” the researcher elaborates, convinced.
Photos: Baohu Wu, Bernhard Ludewig, Phonlamai Photo/Shutterstock