Versatile, High-Power, Flexible, Stretchable Carbon Nanotube Sheet Heating Elements Tolerant to Mechanical Damage and Severe Deformation

A macroscopic carbon nanotube (CNT) sheet-based heating element having flexible, stretchable, and damage-tolerant features, and wide applicability in harsh environments, is introduced. Because of the intrinsic connection of extremely flexible CNT bundles throughout the sample by van der Waals interactions without use of a binder, the electrical resistance variation of the CNT sheet on elastomer heating element as a function of strain is completely suppressed to some extent, even when stretched under up to 400% strain, which guarantees electrical stability under severe mechanical deformation. In addition, the spatial uniformity of the heat generated from the microaligned CNT bundles reduces the temperature variation inside the sample, which also guarantees thermal stability and operation at a higher average temperature. Such exceptional performance is achieved by the passivation of the elastomer layer on the CNT sheets. Furthermore, the mechanical robustness of this flexible, stretchable heating element is demonstrated by stable heater operation, even when the heating element is damaged. In addition, this design concept of CNT sheet on elastomer is extended to transparent flexible heaters and electric-thermochromic windows.