Carbon nanotube/polyurethane core–sheath nanocomposite fibers for wearable strain sensors and electro-thermochromic textiles

Abstract

Color-changing has a wide application including electronic display, military camouflage, intelligent switch, intelligent sensor and intelligent fabric. However, slow response, poor controllability and stability are the challenges affecting the currently application of flexible thermochromic materials. This work aims at designing and constructing hierarchical structure of core-coated electro-thermochromic carbon nanotube/polyurethane composite fibers (ECPF) by impregnation and electrospinning, resulting in color-rich and electro-driven thermochromic composite fibers. The results showed that the temperature on the surface of the composite fiber increased from 25 °C to 66.4 °C and the color changed from red to yellow with the voltage of 9 V applied to both ends of ECPF respectively. The color spectrum of ECPF can be achieved by adjusting the type of color-changing inks, and different patterns of discolored textiles can be realized by weaving. In addition, ECPF composite fibers have excellent conductivity, high sensitivity, a wide strain range (0%–310% strain) and excellent durability (>2000 cycles). The ECPF composite fibers can not only detect human micro-movement, but also exhibit a large strain range more than twice the original length. This work contributes a novel strategy of developing multi-functional electro-thermochromic nanocomposite fibers with color-changing performance and wearable electronic applications for health and human movements monitoring.