Imagine wearing a garment that could generate electricity to power small electronics or monitor your health—all while remaining lightweight, flexible, and safe for everyday use. Researchers at Chalmers University of Technology in Sweden have developed a silk thread coated with a conductive plastic material, paving the way for textiles that function as electricity generators. This new development could be of great interest to fashion designers, product designers, and those working with wearable technologies.

Thermoelectric Textiles: Converting Heat into Power
The technology behind this innovation lies in thermoelectric textiles, which convert temperature differences—such as those between the body and the surrounding air—into electrical energy. This kind of technology has broad potential applications in the design world, particularly in the fashion industry, where functional and smart clothing is becoming a key trend. For product designers, the possibilities extend to integrating energy-harvesting capabilities into other items, such as accessories or furniture coverings, enhancing their utility and sustainability.

Sustainable and Safe Materials
A key advantage of this development is its emphasis on sustainability and material safety. The silk thread is coated with a conductive polymer, a plastic that conducts electricity due to its special chemical structure. According to Mariavittoria Craighero, a doctoral student at the Department of Chemistry and Chemical Engineering at Chalmers University, the polymers are non-toxic, bendable, and lightweight, making them ideal for use in wearable textiles. Furthermore, by focusing on organic, carbon-based polymers, the researchers have managed to eliminate the need for rare earth metals, which are commonly used in electronics but have significant environmental and ethical drawbacks.

Improved Conductivity and Stability
The method used to create the electrically conductive thread has evolved from previous studies, moving away from the use of metals and instead relying solely on organic materials. The new thread developed in the study shows improved electrical conductivity and stability, even when exposed to air. This progress is attributed to a recently discovered polymer with excellent stability and conductivity characteristics. The use of purely organic materials also means that the environmental impact is reduced, aligning with current trends in circularity and the use of biobased materials.

Prototype Demonstrations
To demonstrate the effectiveness of the new conductive thread, the researchers created two prototypes: a thermoelectric button and a piece of fabric with sewn-in conductive threads. These prototypes generated an electrical voltage when placed between a hot and cold surface, indicating their potential as energy-harvesting textiles. For example, a fabric patch produced around 6 millivolts when exposed to a temperature difference of 30 degrees Celsius. In combination with a voltage converter, this energy could theoretically be used to charge portable electronics via a USB connection.

Durability and Challenges in Scaling Up
The textile also proved to be durable, withstanding machine washing while retaining most of its conductive properties. After seven washes, the thread maintained around two-thirds of its conductivity, which is promising for real-world applications but still requires improvement for commercial use. Currently, the process of creating these textiles is time-intensive, requiring manual sewing and careful handling. However, the researchers believe that scaling up production through automated processes is feasible.

Potential Applications and Future Outlook
The potential applications for this material are vast, especially for designers focusing on functional, interactive, and sustainable products. From smart garments that provide health monitoring to textile-integrated chargers for everyday gadgets, the technology represents a significant step forward in merging sustainability with innovation in the design world. As the research progresses, the automated production of such conductive textiles could make them a common element in everyday wear and design.

Source: Chalmers University of Technology
Chalmers University of Technology / Hanna Magnusson