Superhydrophobic encapsulation of flexible Bi2Te3/CNT coated thermoelectric fabric via layer-by-layer assembly

Abstract

Abstract Fabric based flexible thermoelectric materials capable of converting body heat to electricity are promising in self-powered wearable electronic applications. To improve the thermoelectric performance and the wearability of fabric based thermoelectric materials, a superhydrophobic encapsulated Bi2Te3/CNT thermoelectric fabric was introduced. Through layer-by-layer assembly process, Bi2Te3 and CNT were coated onto the surface of cotton fabric substrate, respectively. The prepared thermoelectric fabric has great flexibility and a power factor of 0.15µW·m− 1·K− 2. A thermoelectric generator consists of five Bi2Te3/CNT fabric legs could generate an output voltage of 1.8mV under a temperature difference of 30°C and could be easily attached to the end of sleeves or socks. A double layer superhydrophobic encapsulation composed of silicone, PDMS and PMMA was coated onto the surface of Bi2Te3/CNT fabric to isolated it from the ambient environment. The encapsulation layer, with a water contact angle of 158.6° and a sliding angle of 6.5°, exhibits great self-cleaning property and flexibility. This concept of superhydrophobic thermoelectric fabric paves new way to improve the durability and wearability of thermoelectric generators.