Haute Couture with Carbon Nanotube Bracelets
April 26, 2019
Kyung Tae Park from Korea Institute of Science and Technology and Seoul National University presented a very interesting and engaging talk titled "Carbon Nanotube Based Thermoelectric Bracelet Fabricated by Direct Printing on a Flexible Cable" as a part of symposium EP13: Thermoelectrics - Materials, Methods and Devices on the last day of the 2019 MRS Spring Conference. This was an intriguing application of carbon nanotube (CNT) based thermoelectric (TE) wearable devices, taking into account the various requirements for wearables.
Park started with how there are certain requirements that wearable TE devices have to meet in order to perform well and also be comfortable. These include good TE performance, a preference of out-of-plane architecture over in-plane especially for body heat harvesting where the temperature gradient is also out-of-plane, lightweight, flexible, and conformable. Various materials have been investigated for this application but they all have their pros and cons. Inorganic semiconductors have the highest power factors but are brittle and toxic, conducting polymers are flexible and lightweight but have low power factors and are difficult to obtain in the n-type form. Hence, Park used doped CNTs which are flexible, lightweight, stable, and have power factors that are better than conducting polymers but lower than inorganic semiconductors. By creating p-type CNTs doped with polyacrylic acid and n-type CNTs doped with polyethyleneimine, they were able to create a viscous printing ink that was further deposited on a 3D cable that could be worn for energy harvesting applications. The reported output voltage was 41.4 milliVolts and the bracelet showed very little change in its resistance even after undergoing 3500 bending and unbending cycles.
To read more about this research, please click here.
Comments