CNT/cotton composite yarn for electro-thermochromic textiles

Abstract

Electro-thermochromic yarn was prepared by wrapping pure cotton yarn on carbon nanotube/cotton composite yarn. The CNT/cotton composite yarn as the core yarn provides good electrical conductivity while the pure cotton yarn as the wrapped yarn plays a protective role and enables the color changing effect after coating with thermochromic inks. The electro-thermochromic yarn showed remarkable resistive heating and color-changing properties under different applied currents. Abundant and reversible color changes are clearly observed by coating the thermochromic inks onto the surface of yarn and fabric. Depends on the methods, a pure color changing fabric can be made from the electro-thermochromic yarns and fabrics with color changing patterns can be achieved by printing the thermochromic inks into the fabrics from the CNT/cotton cored yarn. Moreover, when the current is 5 mA, the surface temperature of the CNT/cotton cored yarn can increase within several seconds to its maximum 60 °C. The average temperature of the electro-thermochromic fabric can reach up to 90 °C under 4 mA. The printed pattern changes color from deep rose to yellow when a current of 4 mA is applied on the electro-thermochromic fabric. The electro-thermochromic yarns and fabrics show repeatable and reversible color changing effects.