Yanliang Zhang is an associate professor in aerospace and mechanical engineering and Yipu Du is a doctoral student. Credit: University of Notre Dame
Most people associate wearable devices with smart watches, smart glasses and fitness trackers. These devices are part of a rapidly growing market. They all need external power sources and require precise manufacturing processes. Until now.
Yanliang Zhang, an associate professor of aerospace engineering and mechanical engineering at the University of Notre Dame and Yipu Du, a doctoral student, have developed a hybrid printing process that combines multi-material extrusion printing and aerosol jet printing. This combines both structural and functional materials into one streamlined printing platform. Their work was published in Nano Energy.
Zhang and Du have also developed an all-printed, self-powered, piezoelectric wearable device in collaboration with Wenzhuo Wu's team at Purdue University.
The team developed stretchable piezoelectric sensors that conform to human skin using a hybrid printing process. They also included tellurium nanowire pizoelectric materials, silver electrodes, and silicone films. The team printed the devices and attached them to the wrists of humans to detect hand gestures. The devices did not use an external power source.
Piezoelectric materials are one of the most promising materials for the production of wearable electronics. They generate their own electricity from mechanical stress, instead of being powered by a source.
Printing piezoelectric devices can be difficult because they require high electric fields and high sintering temperatures. This increases the cost and time of printing and can cause damage to surrounding materials during sensor integration.
Zhang stated that the greatest advantage of hybrid printing is its ability to incorporate a wide variety of structural and functional materials into one platform.
This streamlines the manufacturing process, which reduces time and energy required to produce a device. It also ensures that printed devices perform as well.
Zhang said that nanostructured materials with piezoelectric characteristics are crucial to the design. These properties eliminate the need to sinter or poling and are also important for wearable devices that attach to bodies in motion.
Zhang stated, "We are excited to see the wide variety of opportunities that will open for printed electronics as well as wearable devices due to this very versatile printing process."
Further reading: Flexible wearable electronics for smart devices
Information: Yipu Du et al., Hybrid print of wearable piezoelectric sensor, Nano Energy (2021). Information from the Journal: Nano Energy Yipu Du et al., Hybrid print of wearable piezoelectric sensor, (2021). DOI: 10.1016/j.nanoen.2021.106522
