Highly robust and durable core-sheath nanocomposite yarns for electro-thermochromic performance application.

• Durable core-sheath electro-thermochromic CNT/cotton composite yarn was fabricated. • The yarn shows excellent mechanical properties and thermochromic performance. • The yarn exhibits excellent electrified heating performance with stability. • The yarn is durable against mechanical deformations, washing and chemicals. • The color of the yarn can be tuned by changing the applied current for design. A core-sheath nanocomposite yarn, with CNT/cotton composite yarn (CCY) as the core and nanofibrous polyurethane/temperature sensitive ink as the sheath, was fabricated to generate highly robust and durable electro-thermochromic performance. Due to its novel core-sheath nanocomposite structure, the as-fabricated electro-thermochromic composite yarn (ECCY) brought together the excellent mechanical properties and electrothermal properties together with electrochromic performance. The ECCY exhibited excellent electrified heating performance with stability even after 100 cycles of heating/cooling. Moreover, the ECCY showed excellent durability against repeated bending, twisting and stretching, washing and even soaking in acid and alkali solutions. The color of ECCY was successfully tuned via changing the applied current. In addition, the ECCY was used to design different patterns and to form a fabric, resulting in color conversion patterns/fabrics when applying/releasing a current. This work provides a novel strategy of developing electro-thermochromic composite yarn by designing the core-sheath micro-nano fibrous composite structure. The highly robust and durable performance of yarn will benefit its applications as wearable electronics. [ABSTRACT FROM AUTHOR]