Researchers at the University of Tokyo have created a new ink that can be printed on textiles to form a highly conductive circuit using a single printing step.
The elastic conducting ink consists of silver flakes, organic solvent, fluorine rubber and fluorine surfactant.
It is capable of retaining its high conductivity even when stretched to more than three times its original length.
Until now, printed electronics, such as transistors and light emitted diodes, were printed on plastic or paper substrates because the substrates tend to be rigid or hard, but the new ink is both highly conductive and elastic.
The researchers, led by Professor Takao Someya, created a wristband muscle activity sensor by using the ink to print an elastic conductor on a sportswear material combined with an organic transistor amplifier circuit.
The new technology is expected to be used in myoelectric sensors on sportswear for training purposes, with the sensors able to collect biological information like pulse and brain waves that can be used for medical and welfare purposes.
Someya added: "Our team aims to develop comfortable wearable devices. This ink was developed as part of this endeavour.
"The biggest challenge was obtaining high conductivity and stretchability with a simple one-step printing process.
"We were able to achieve this by use of a surfactant that allowed the silver flakes to self-assemble at the surface of the printed pattern, ensuring high conductivity."
