Electrothermochromic Fabrics with a Single-Layer Functional Coating Based on Silver Nanowires/Thermochromic Microcapsules/Waterborne Polyurethane Paints

The Ag NWs/TCMs/WPU/PET fabric was prepared by coating the polyester (PET) fabric with Ag NWs/TCMs/WPU paint. First, an electrothermochromic paint was fabricated by incorporating waterborne polyurethane (WPU) and thermochromic microcapsules (TCMs) into silver nanowire (Ag NW) dispersions, and then the Ag NWs/TCMs/WPU paint was applied to polyester (PET) fabrics via brushing, thereby integrating electrothermal and color-changing properties into a single functional layer. The color change test and DSC data demonstrate that the Ag NWs/TCMs/WPU paint exhibits a reversible color change effect, and the flexibility test data indicate that the coating's resistance remains essentially unchanged after 1000 bending cycles. The sheet resistance of the Ag NWs/TCMs/WPU/PET fabric is 8.62 Ω·sq^-1. Electrothermal tests show that the fabric surface temperature reaches 48.9 °C at 4 V, triggering a color change. Varying the type of TCMs yields electrothermochromic fabrics exhibiting two distinct color-changing effects at 4 and 6 V. Following 50 cycles of washing and rubbing, the fabric's resistance remains within the same order of magnitude, and the color change is minimal. The Ag NWs/TCMs/WPU/PET fabric, featuring a straightforward preparation method, a rich color-changing effect, and excellent durability, is poised for application in smart color-changing textiles.