Electronic clothing offers new opportunities in a number of areas, particularly healthcare. But to be sustainable, they must be made of renewable materials. A research team led by Chalmers University of Technology, Sweden, is now showcasing a fiber made of conductive cellulose, which offers exciting and practical opportunities for electronic clothing.
Using a conventional household sewing machine, researchers have sewn the electronic cellulose yarn into a garment and succeeded in making a thermoelectronic garment, which can generate some electricity when the garment is worn. heated on one side, for example by the heat of a person’s body. Photo: Anna-Lena Lundqvist, Chalmers
“Small electronic, consumable, electronic devices are ever more common in our daily lives. But for now, they are often dependent on rare, or in some cases toxic, substances. They also lead to the gradual construction of huge mountains of electronic waste. There is a real need for organic, renewable materials for use in electronic clothing, ”said Sozan Darabi, a doctoral student at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology and the Wallenberg Forest Science Center, and lead author of the last scientific article. recently published in ASC Applied Materials & Interface.
Together with Anja Lund, a researcher in the same group, Sozan Darabi has been working with electronic fiber for electronic clothing for several years. The previous focus was on silk, but now the traces have been advanced through the use of cellulose.
Built-in electronics in non-toxic, renewable and natural materials
The results of the researchers now show how cellulose fiber offers great potential as a material for electronic clothing and can be used in many different ways.
Sewing the electronic cellulose threads into fabric using a conventional home sewing machine, the researchers have now successfully made a thermoelectric fabric that emits a small amount of electricity when sewn. heating on one side – for example, with human body heat. At a temperature difference of 37 degrees Celsius, the fabric can generate around 0.2 microwatts of electricity.
This cellulose fiber could lead to fabrics with electronic, elegant functions, made with non-toxic, renewable and natural materials. “
Sozan Darabi, doctoral student at the Department of Chemistry and Chemical Engineering, Chalmers University of Technology and Wallenberg Forest Science Center
The production process for the cellulose fiber was developed by co-authors from Aalto University in Finland. In a subsequent process, the Chalmers researchers fabricated the yarn by dyeing it with an electronic polymeric material. The researchers’ measurements show that the dyeing process gives the cellulose yarn a high conductivity – which can be increased even further by the addition of silver nanowires. In experiments, the conductivity was maintained after several washes.
Benefits of e-clothing and cellulose
Electronic clothing can improve our lives in a number of ways. Healthcare is one important area, where activities such as the management, monitoring, and measurement of various health metrics can be very beneficial.
In the wider apparel industry, where switching to sustainable raw materials is a critical ongoing issue, natural and fiber materials have become an increasingly common alternative to synthetics. Electronic cellulose fibers could play a major role in playing this, the researchers say.
Cellulose is a unique material that can be extracted and recycled sustainably, and we see that it will be used more and more in the future. And when products are made from clothing material, or as few materials as possible, the recycling process becomes much easier and more efficient. This is another view from which cellulose fiber is very promising for e-clothing development. ”
Christian Müller, Director of research studies and professor at the Department of Chemistry and Chemical Engineering, Chalmers University of Technology
The work of the research team from Chalmers is carried out within the national research center of the Wallenberg Forest Science Center, in collaboration with colleagues in Sweden, Finland and South Korea.
Read the article in the scientific journal ASC Applied Materials & Interface: Green carrying cellulose yarn for sewing machine electronic clothing
More about: Developing knowledge in behavioral fiber
Both Sozan Darabi and Christian Müller believe the research has led to much more than just the latest scientific publication. Sozan Darabi has evolved from being a student to becoming a leading expert in electronic fiber products, something Christian Müller sees as a real reward, and a strong strength for their research team.
Through the Swedish national research center Wallenberg Forest Science Center, a group from the Royal Stockholm Institute of Technology (KTH) has also been involved in the research and publication of the study. The KTH researchers focus on the electrochemical aspects of the fibers. Together with this group from KTH, the Chalmers research team is now devising ways to take the ideas to the next level.
Also read earlier press release: Electric clothing lights up a lamp when stretched
More about: The cellulose fiber
The electronic yarn is extracted in a “surface-to-surface” coating process with an ink based on the biocompatible polymer “poly complex polyyelectrolyte (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) ”. An e-fabric developed by the researchers measures high conductivity for cellulose fibers with a size of 36 S / cm-, which can be increased to 181 S / cm by the addition of silver nanowires. The thread is covered by PEDOT: PSS can handle at least five machine washes without losing their conductivity. By integrating the cellulose yarn into an electrochemical transistor, the researchers have also been able to demonstrate its electrochemical function.
More about: Clothing products from interest in nature and fashion industry
Throughout human history, clothing has been made from natural fiber and cellulose. But since the mid-20th century, synthetic fibers have become more common in our clothing, especially in the fashion industry. With more focus and awareness now of sustainable alternatives, interest in natural fibers and textiles is returning and growing. Large Swedish chains such as H&M and Lindex have set high goals for increasing the amount of clothing made from more durable materials.
The cellulose fiber used by the researchers is from the Ioncell® type, developed by the Finnish group, led by professor and co-author Herbert Sixta.
Source:
Chalmers University of Technology
Magazine Reference:
Darabi, S., et al. (2021) Transport green cellulose yarn for sewing machine electronic clothing. Applied Materials & ACS Interface. doi.org/10.1021/acsami.0c15399.