Trends in wearable technology

Materials World magazine
,
1 Feb 2016

In the year when wearable technology is expected to soar, Natalie Daniels looks at the current trends in smart technology. 

From app-compatible clothes to skin sensors and stickers, wearable technology is fast becoming a favourite for manufacturers from Apple watches to Fitbits and smart rings. Textile R&D company Tamicare, UK, has come up with a new way to mass-produce 3D printed textiles with the addition of wearable smart technology, named Cosyflex. Tim Harper, Graphene Consultant for Tamicare said, ‘The idea behind the technology began when we first asked ourselves “What if we could just move the substrate and keep the print heads where they are, and in doing so, essentially the process creates a circular production line?” The first production line is being commissioned, and will produce around 3 million units a year, with a fairly small footprint.’ This will help secure Tamicare the status of the first company to mass produce 3D-printed textiles.

Harper describes the process, ‘We start with a base plate, which is the same as a pattern for conventional textiles, using that as the template for the garment pattern. The first thing is to add a water-based gel, then we electrostatically flock the fibres depending on what material it is – it can be wool, cotton or silk. Then it is a question of building it up layer-by-layer – once we have the flock, layers of other materials, such as natural latex, can be added. Because we are printing, anything can be incorporated – graphene, carbon black or boron nitride to either make the textiles conductive, create circuitry or print sensors, essentially creating wearable technology.’

To complete the garment, Tamicare adds another layer of flock. The template is then passed through an oven, which cures all the materials, and evaporates the water-based gel. Following this, robots complete the stitching, welding and forming. ‘By doing it this way, there is a circular production line. Once the garment has been taken off the template, it then goes round and you build up the next garment. This is a process that happens very quickly and means you can be in constant production of textiles or devices,’ adds Harper.

The company has recently signed a deal with a major sportswear brand, looking to enter the wearable technology market. ‘The really interesting bit is this idea that we can now start integrating sensors into the fabrics. Everyone is trying to come up with smart clothing, but they will often just take conventional textiles, put in some conductive yarn or fibres and basically have to stick something to the textile. Cosyflex allows us to integrate these sensors into the material,’ Harper said. 

Using 3D printing, Tamicare is able to produce a garment and sensor at the same time, providing the materials can be printed or sprayed on, depending on the application. ‘Then, it is completely integrated into the process,’ explains Harper. 

Graphene – fit for wear?

Graphene has proved a popular material choice for wearables over the past few months with more researchers attempting to understand how this 2D material can be applied to textiles for smart clothing and smart skin applications. ‘We are currently working with graphene for a couple of applications – the main one is as a sensor. The indications are that we should be able to integrate it into the production process with graphene manufacturers helping us to get the inks into the right state,’ says Harper. But Tamicare isn’t the only one developing graphene in garments – researchers at the University of Manchester, UK, have demonstrated how the material could be crucial to wearable electronics because of its high conductivity and flexibility. 

The researchers, led by Dr Zhirun Hu, printed graphene to construct transmission lines and antennas, experimenting with these in mobile devices and wifi connectivity. Using a mannequin, the researchers attached graphene-enabled antennas to each arm. The devices were able to talk to each other effectively, creating an on-body communications system. The results proved that graphene enabled components to have the required quality and functionality for wireless wearable devices. Dr Hu states, ‘Printed graphene can be used to make flexible radio-frequency identification tags and sensors and printed-on clothes. This technology could be used for healthcare, sports monitoring, smart skin and functional clothes, to name a few.’ The researchers believe this is a significant step forward and graphene-enabled wireless wearable communications systems could be available in the near future. 

However, despite ongoing efforts, Harper believes ‘the biggest challenge with new and advanced materials like graphene is that nobody quite knows what the applications are going to be. Once applications like wearable technology come through, in terms of people knowing exactly what they want and the quantities, then you have got some real market pull.’ 

Medical monitoring

Other efforts in wearables have been made by a team of scientists at Seoul National University, South Korea, who have designed an ultra-thin, stretchable electronic device using gold nanoparticles, which sticks onto the skin to monitor a person’s heart rate. The circuit is made from a stretchable silicon membrane containing gold nanoparticles, which offer good chemical stability and long-term memory storage. The device contains electrocardiogram sensors and amplifiers that monitor heart rate, while conforming to the patient’s skin. Lead researcher, Dae-Hyeong Kim states, ‘The technology in this work provides a new wearable platform for the flash memory and signal amplification devices that are important for continuous monitoring and data storage of a patient's healthcare information.’ 

Too much sun?

Even beauty products are turning to wearable technology. L’Oréal recently announced its smart skin patch, at CES 2016 in Las Vegas, designed to track the skin's level of exposure to ultraviolet (UV) rays and signal to a smartphone app. Created in conjunction with PCH, an Irish product engineering firm, the stretchable sensor, with a diameter of 25mm and thickness of 15 microns, contains flexible electronics that can be worn on the skin anywhere and that, with the help of a smartphone, can tell the user how much UV exposure they are subject to at any time of the day. 

For more information on the Tamicare smart textiles, contact timharper23@mac.com