The electrothermal color-changing fabric based on high-sensitivity thermochromic microcapsules

High sensitivity including low color hydrolysis and a narrow temperature range of color-changing is important to thermochromic microcapsules. However, it is a challenge for conventional ternary thermochromic systems to realize the fast change of colors. A new class of high-sensitivity microcapsules and electrothermal color-changing fabrics were designed and synthesized by introducing CNTs into thermochromic systems via microencapsulation and coating technology. The high sensitivity was attributed to the enhanced filler CNTs and binary core phase change materials (1-Tetradecanol/1-Octadecanol). Moreover, the dosage amount of CNTs, core-to-shell ratios, and particle size on the temperature sensitivity of microcapsules were investigated. From the results, the optimized microcapsules with regular spherical shape exhibited a narrow color-change temperature range of 30–35 ℃ and low color hydrolysis of 11 ℃. As the core wall ratio increased from 1:1–3:1, the color change temperature range of microcapsules became narrower and the color hydrolysis was lower. According to the phase change behaviors, thermochromic microcapsules with a melting enthalpy of 70.64 J/g performed a good thermal regulation capacity. Furthermore, the reversible thermochromic performance of obtained microcapsules remained stable through 500 thermal cycles, demonstrating excellent thermal cycling stability. Combining the obtained microcapsules and electrothermal fabrics, highly sensitive electro-thermochromic (ETC) fabrics by voltage were prepared. Under the supplied voltage of 6 V, the ETC fabrics exhibited outstanding cyclic electrothermal color-changing performance. This unique design concept for high-sensitivity ETC fabrics has great potential applications in personal thermal management, the cooling of electronic devices, visible displays, and so on.