E-textiles, materials with embedded electrical components, hold promise for a range of uses from medical to sports performance. While the durability and safety of these textiles is essential, dealing with the textile waste comes with challenges.
Now a research team led by the UK’s University of Southampton and UWE Bristol has tested a new sustainable approach for fully inkjet-printed, eco-friendly e-textiles. The three-layer design incorporates the widely-used textile Tencel. Made from renewable wood and biodegradable, the Tencel forms the base of the three layer concept, the other two are a sensing layer and one to interface with the sensors and the base layer.
The active electronics in the design are made from graphene along with a polymer known as PEDOT: PSS a composite polymer where PEDOT (poly (3,4-ethoylenedioxythiophene)) provides electrical conductivity and PSS (polystyrene sulphonate) acts as a counter ion to balance the charge and improve water solubility. These conductive materials are precision inkjet-printed onto the fabric.
Publishing the research in the journal Energy and Environmental Materials Professor Nazmul Karim, at the University of Southampton’s Winchester School of Art, who led the study said: “Integrating electrical components into conventional textiles complicates the recycling of the material because it often contains metals, such as silver, that don’t easily biodegrade. Our potentially eco-friendly approach for selecting sustainable materials and manufacturing overcomes this, enabling the fabric to decompose when it is disposed of.”
The new material which can be fully inkjet-printed, is known as Smart, Wearable, and Eco-friendly Electronic Textiles (SWEET) and involved collaborators from the universities of Exeter, Cambridge, Leeds and Bath. Tests have been conducted which indicate that SWEET can reliably measure both heart rate and temperature to industry standards. The researchers point out that the inkjet printing process is more sustainable for e-textile fabrications, depositing the exact number of functional materials needed, cutting down on material waste and reducing the use of water and energy when compared to conventional screen printing.
Marzia Dulal from UWE Bristol, a Commonwealth PhD Scholar and the first author of the study said: “Our life cycle analysis shows that graphene-based e-textiles have a fraction of the environmental footprint compared to traditional electronics. This makes them a more responsible choice for industries looking to reduce their ecological impact.”
Further tests also indicated that the material is biodegradable, losing 48% of its weight and 98% of its strength four months after being buried. Life cycle assessments also indicate that the graphene-based electrodes have up to 40 times less impact on the environment than standard electrodes.
“These materials will become increasingly more important in out lives,” Dr Karim added “particularly in the area of healthcare so it’s really important we consider how to make them more eco-friendly, both in their manufacturing and disposal.”
The researchers are now looking to design wearable garments made form SWEET for use in the healthcare sector, particularly in the area of early detection and prevention of heart-related diseases which is said to impact some 640 million people worldwide.
Smart textiles is a growing market which during 2022 was valued at $4.3 billion and is finding application in products from wound dressings to shoe insoles for running or materials measuring muscle strength.
Further reading:
• Sustainability and use of chemicals in textiles in the spotlight
• A Singapore business collaborates with academics to tackle textile waste
• Could this be the route from plastic bag to T-shirt?
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