Screen printing creates durable circuits for fabric wearables

Screen printing can be used to create a stretchable, durable circuit pattern that can be transferred to fabric and worn directly on human skin.

A set of screen-printed electrodes
A set of screen-printed electrodes - Washington State University

This is the claim of a team led by researchers at Washington State University who believe this form of wearable electronics can be used for health monitoring in hospitals or at home. Their results have been published in ACS Applied Materials and Interfaces.

“We wanted to make flexible, wearable electronics in a way that is much easier, more convenient and lower cost,” said corresponding author Jong-Hoon Kim, associate professor at the WSU Vancouver’s School of Engineering and Computer Science. “That’s why we focused on screen printing: it's easy to use. It has a simple setup, and it is suitable for mass production.”

Current commercial manufacturing of wearable electronics requires expensive processes involving clean rooms. While some use screen printing for parts of the process, this new method relies entirely on screen printing, which has advantages for manufacturers and consumers alike.

In the study, Kim and his colleagues detail the electrode screen-printing process and demonstrate how the resulting electrodes can be used for electrocardiogram (ECG) monitoring.

MORE FROM WEARABLE TECHNOLOGY

They are said to have used a multi-step process to layer polymer and metal inks to create serpentine-like structures of the electrode. While the resulting thin pattern appears delicate, the electrodes can be stretched by 30 per cent and bend to 180 degrees.

Multiple electrodes are printed onto a pre-treated glass slide, which allows them to be easily peeled off and transferred onto fabric or other material. After printing the electrodes, the researchers transferred them onto an adhesive fabric that was then worn directly on the skin by volunteers. The wireless electrodes accurately recorded heart and respiratory rates, sending the data to a mobile phone.

While this study focused on ECG monitoring, the screen-printing process can be used to create electrodes for a range of uses, including those that serve similar functions to smart watches or fitness trackers, Kim said in a statement.

Kim’s lab is currently working on expanding this technology to print different electrodes as well as entire electronic chips and even potentially whole circuit boards. 

In addition to Kim, co-authors on the study includes researchers from the Georgia Institute of Technology and Pukyong National University in South Korea as well as others from WSU Vancouver. This research received support from the National Science Foundation.