Sunlight‐Responsive Photothermochromic Fabric with Reversible Color Changing Based on Photothermal Conversion

Intelligent color‐changing textiles have attracted increasing attention due to their potential application in healthcare monitoring and artificial intelligence. To realize the active modulation of color via sunlight, the photothermochromic fabric that adjusts its color based on the photothermal conversion performance of the sunlight‐responsive heating layer under irradiation of solar is fabricated by double‐side coating. Depending on the light absorption at 350–2500 nm, the sunlight‐responsive photothermochromic fabric (SPTCF) exposed under the irradiation power density of 500 W m −2 for 4 min displays efficient photothermal conversion, resulting in the increase in temperature from room temperature (23.0 °C) to above 47.0 °C. Simultaneously, the color of SPTCF changes from blue to white and returns to blue once the light is turned off for 3 min, indicating the sensitive and reversible photothermochromic property of the SPTCF. Compared with the contrast layer, the sunlight‐responsive heating layer exhibits a rapid photothermal conversion speed and high optical contrast under the same irradiation condition. The heating/cooling curves show steady signals after mechanical deformations and 150 cycles, revealing the favorable durability of the SPTCF under the solar irradiation. The sensitive photothermochromic properties promote the application of the SPTCF in smart wearable fields.