New Wearable 3D Temperature Printing Technology

From health monitoring, fitness tracker to virtual reality headset, wearable electronic products have become a part of our daily life. Researchers at the University of Washington recently published a paper in the journal advanced energy materials that they have developed a flexible wearable thermoelectric device that can convert body heat into electrical energy. The device has features that are often difficult to combine: soft and stretchable, strong and efficient.

Mohamed malakudi, an assistant professor of mechanical industry at the University of Washington, said: "If we collect the heat energy that is wasted in the environment, that's 100% of the revenue. But to use this energy for self powered electronic devices, a higher power density is needed. Using 3D printing to create stretchable electronics can improve efficiency and integrate them seamlessly into wearable devices."

Researchers have built a prototype device that remains fully functional even after 15000 tensile cycles at 30% strain, ideal for wearable electronic devices and flexible robots. The power density of the device is increased by 6.5 times compared with the previous stretchable thermoelectric generator.

To make the prototype, the researchers 3D printed composite materials with engineering functions and structural properties at each layer. The filling material contains liquid metal alloy, which can provide high conductivity and thermal conductivity. These alloys address the limitations of previous equipment, including inability to stretch, inefficient heat transfer, and complex manufacturing processes. The team also embeds hollow microspheres that direct heat to the core layer of semiconductors and reduce the weight of the device.

The researchers said they could print the device on stretchable textile fabrics and surfaces, suggesting that future devices could be used for clothing and other objects. A unique aspect of the research is that it covers the entire range from material synthesis to device manufacturing and characterization, which gives researchers the freedom to design new materials and to be creative.