Preparation and Properties of Green-yellow Reversible Electro-thermochromic Fabric

Graphene has played a major role in wearable electronic textiles due to its excellent electrical conductivity, superior flexibility and environmental stability.In this work, a green-yellow reversible electrothermochromic fabric was constructed via a facial double side coating.The self-made graphene paste is coated on the surface of polyester fabric by screen printing technology.The hybrid thermochromic ink with reversible color-changing property is coated on the opposite side of the graphene layer by screen printing technology.Structural properties and discoloration principle of the fabric were analyzed.Their thermal and color-changing properties were studied by using infrared thermal imaging and colorimeter.The results show that the graphene forms a conductive layer with a thickness of 250 μm that allows Joule heating to supply the thermal resource for the electrothermochromic behavior.This fabric changes from green to yellow with a gradual heating that exceeded 45 ℃ at 12 V due to the ring closure and opening of crystal violet lactone.Its color change response time is about15 s, while fading response time is about 27 s.The electro-thermochromic fabric is not disturbed once undergoing a bending angle range from 30° to 180° and the voltage-current curve remains stable.Performance of the fabric does not significantly degrade after 200 heating/cooling continuous cycles.In conclusion, a sensitive electro-thermochromic fabric with good cycle performance from green to yellow with the structure of graphene film‖polyester fabric‖thermochromic film is successfully prepared, which has a high application potential in the fields of wearable display.