Researchers at the University of Cambridge have developed a wearable electronic component that is incorporated directly into fabrics. The device could be used for healthcare monitoring, flexible circuits, energy conversion and other applications.
The researchers from Cambridge worked with their colleagues at Jiangnan University in China and they have shown how graphene, a known two-dimensional form of carbon- and other materials can be incorporated into fabrics to create charge storage elements such as capacitors, making the way to power supplies that are textile-based and are washable, flexible and comfortable to wear.
The research was published in the journal Nanoscale, shows that graphene inks can be used in textiles able to store electrical charge and release it when needed. The new electronic devices on the textile are based on sustainable, low-cost and scalable dyeing of polyester fabric. The inks are made by standard solution processing techniques.
Referring to the work done by the same team years before, the researchers made inks which can be coated onto a polyester fabric directly and it can be done by a dyeing process. The process allows different types of electronic components to be incorporated into the fabric.
Most of the other wearable electronics rely on electronic components that are rigid and just mounted on textiles or plastic. These have limited compatibility with the skin and are damaged when washed and they are uncomfortable to wear because they are not breathable.
"Other techniques to incorporate electronic components directly into textiles are expensive to produce and usually require toxic solvents, which makes them unsuitable to be worn," said Dr. Felice Torrisi from the Cambridge Graphene Centre, and the paper's corresponding author.
"Our inks are cheap, safe and environmentally-friendly, and can be combined to create electronic circuits by simply overlaying different fabrics made of two-dimensional materials on the fabric."
The researchers suspended graphene sheets individually in a low boiling point solvent, which is removed easily after deposition on the fabric. This results in a uniform and thin conducting network made up of many graphene sheets. The overlay of numerous graphene and hexagonal boron nitride fabrics make an active region which creates a charged storage. This "battery" on fabric is bendable and it can withstand washing cycles in a normal washing machine.
"Textile dyeing has been around for centuries using simple pigments, but our result demonstrates for the first time that inks based on graphene and related materials can be used to produce textiles that could store and release energy," said co-author Professor Chaoxia Wang from Jiangnan University in China.
"Our process is scalable and there are no fundamental obstacles to the technological development of wearable electronic devices both in terms of their complexity and performance."
This development opens a lot of commercial opportunities for ink based on two-dimensional materials, from personal health to wearable energy and data storage. It can also be useful as a wearable computing and military garment as well as fashion.
"Turning textiles into functional energy storage elements can open up an entirely new set of applications, from body-energy harvesting and storage to the Internet of Things," said Torrisi "In the future, our clothes could incorporate these textile-based charge storage elements and power wearable textile devices."
