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All-organic devices in textiles for wearable electronics

Periodic Reporting for period 1 - E-TEX (All-organic devices in textiles for wearable electronics)

Reporting period: 2016-10-01 to 2018-09-30

Smart textiles are an emerging field of research in wearable technology, and since the concept of textiles is much broader than clothes and garments, the range of applications includes healthcare, military, automotive, construction, packaging etc. Most smart textiles are based on simply mounting off the shelf hardware components in fabrics. One of the main limitations of this approach is the integration. Hardware components are rigid and heavy, and therefore not very compatible with textiles.

The issue of integration was one of the main aims of this project, bringing electronics and fabrics closer together. This has been done by building the electronic devices directly on textile fibres using flexible and lightweight materials that can still guarantee the electronic properties needed for different type of devices.

When we think about wearable technology we might visualise watches or bracelets, but the applications are way beyond modern portable electronics. We could potentially harvest energy from the temperature or movement of the user and power their wearable devices. These devices can be sensors monitoring one’s health and transmit data to a carer or doctor, and this can potentially save lives. This is important for remote healthcare at home or at the hospital environment, but also to monitor first responders in an emergency, being exposed to stress and harmful conditions.

The approach in this project consisted in exploring materials that combine outstanding mechanical flexibility, ambient stability, and desirable electronic properties for different functionalities. The main material used was graphene, the “miracle material of the 21st century”. Graphene is a single layer of carbon atoms with high conductivity and optical transparency.

The overall objectives of E-TEX are the development of wearable electronic devices build directly on textile fibres.

The first half of the project went on as planned, optimising and widening the conductive fibres using different polymeric materials and different types of coatings. However, several issues caused the second half to deviate slightly from the initial objectives in terms of the type of devices achieved. Nonetheless we were able to demonstrate several types of wearable electronic devices: energy harvesting generators, touch and position sensors, light-emitting devices, and strain, temperature and humidity sensors.

In conclusion, the E-TEX project was highly successful, and the results will be taken forward in future project opportunities. It was an invaluable opportunity to establish the recipient of the Individual Fellowship as an independent and recognised researcher in my field and move on to a permanent position in the host institution.
The work performed included the involvement of undergraduate and postgraduate students, an important step in the development of my career to become an independent researcher.

The first part of this project was devoted to extending the range of conductive fibres to other materials, shapes, and types of graphene coating (Scientific Reports DOI:10.1038/s41598-017-04453-7).

We demonstrated light-emitting devices using commercial solution-processable flexible materials directly on textile fibres. This includes robust light-emitting fibres and arrays pixels, essential for wearable displays. Keeping our devices as close to manufacturing constraints, namely those of the textile industry, touch and position sensors were also developed, with applications in wearable dials and switches (npj Flexible Electronics DOI: 10.1038/s41528-018-0040-2).

To make graphene coating scalable for future industrialisation and commercialisation, we developed and optimised graphene conductive inks. Using these methods, we demonstrated that is it possible to harvest static charges generated by motion using flexible graphene electrodes, while pioneering a method to produce graphene films from suspensions and easily transferring them onto many substrates, including textiles (Advanced Materials DOI: 10.1002/adma.201802953).

Building on the development of graphene-based inks and formulation, another collaborative work was carried out in developing nanoengineered concrete. Using graphene suspensions instead of just water in the fabrication of concrete structures, we demonstrated that the incorporation of graphene in concrete results in an increase in compressive and flexural strength, but even more importantly, an enormous decrease in water permeability. This work was published in Advanced Functional Materials (DOI:10.1002/adfm.201705183) and very widely featured in the media.

We found that they have the potential to be used for sensing purposes, and collaborating with experts in electronics we demonstrated wireless data transmission from out sensors (IEEE Sensors DOI: 10.1109/ICSENS.2017.8234058).

E-TEX allowed me to attend 17 public events, including 14 international conferences with a strong industrial/exhibition component, for an effective translation of the results. Given the visibility of this fellowship, I gave invited oral presentation at most of these events. The results of this project have been presented by students, researchers and academics all over the world. I was an exhibitor at a trade fair and attended an Innovate UK network event, where I met potential investors, resulting in funding applications and direct investment through contract research and consultancy. Other business opportunities currently under discussion. 3 of these events were student-facing, a great opportunity to talk about my career path and try to inspire younger researchers. I also gave private seminars in companies, universities and research institutes, which is important to extend the network of collaborators.
The results of this project make a significant advance beyond the state of the art at the conception phase. The range of conductive textile fibres was enlarged, both in terms of the type of fibres (material, size, shape), and type of graphene coating (different techniques, different number of layers and properties).

A number of electronic devices were demonstrated, pioneering the use of these conductive platform for many applications. The transformative aspect of this project resides in the fact that these flexible and truly wearable devices are not fabricated on conventional substrates the mounted onto textiles afterwards, they were built directly on textile fibres using novel materials and techniques.

The progress made with this project is paving the way for the development of truly wearable sensing applications. Such sensors can be endowed with wireless communication capabilities, which are very important for the emerging field of remote healthcare, which in the recent era of the Internet-of-things has a huge commercial potential. Recognising this, several companies have shown interest to develop future collaborations and invest in our work. I am currently developing joint projects with them, along with other academic partners, to take the results of E-TEX forward.

In terms of societal implications, the development of wearable devices that are not only capable of sensing or emitting light, but also capable of monitoring the health of the user while adding antibacterial properties, could be hugely beneficial. Such devices could be used in the hospital environment but also in home care, increasing the sense of autonomy of the patient and providing some relief to the carers.
Light emitting arrays (courtesy of Dr Elias Torres Alonso)