Waterborne polyurethane based thermoelectric composites and their application potential in wearable thermoelectric textiles

A fabric based thermoelectric generator with great wearability would overcome the wearable difficulty of existing organic film generators, which shows promising application in flexible and wearable self-powered electronic systems by harvesting body heat to generate electricity. However, to fabricate a wearable fabric thermoelectric generator, yarns with thermoelectric function are indispensable components, since yarns are the basic composition units of fabric structures, which can be treated as thermoelectric legs in a fabric thermoelectric generator. Thus, to give thermoelectric function to yarns, a new water-processable thermoelectric coating material made of waterborne polyurethane, MWCNT and PEDOT:PSS composite was developed. The thermoelectric properties of the composite with different constituents were investigated. The optimal electrical conductivity and Seebeck coefficient could achieve ∼13826 S/m and ∼10 μV/K at room temperature respectively, resulting in a power factor of ∼1.41 μW m−1K−2. In the following coating experiment, the fabricated composite was successfully coated on commercial cotton and polyester yarns respectively. Compared with the staple cotton yarn, the long continuous polyester filament exhibiting better coating layer is more suitable as coating substrate. The fabricated yarns will be the foundation for our next study of fabric TEG.