Functional fabric heater based on silver nanowire/carbon nanotube composites

Abstract

The increasing demand for smart fabrics has inspired extensive research on nanomaterial-based fabric heaters. For diverse applications of these fabric heaters, it must have a low driving voltage, high stretchability, and mechanical stability. In order to obtain the above characteristics, it is important to uniformly coat the fabric substrate with a conductive material. So far, the dip coating method has been used the most. However, it is difficult to be used in practical applications since dip coating method do not allow the patternability. Herein, we propose an improved spray coating method well suited for the preparation of patternable fabric heaters on commercial fabrics, combining the structural stability of carbon nanotubes with the high electrical conductivity of Ag nanowires to fabricate a stretchable fabric heater with excellent mechanical (stretchability ≈ 50 %) and electrical (sheet resistance ≈ $22 \Omega$/□) properties. In addition, this heater shows a stable performance even when folded or rolled, thus being well suited for the practical applications such as a wearable heater, a defrosting heater and an electrothermal actuator. Especially, in the case of electrothermal actuator, a novel control method was developed by applying the above coating process, and it was demonstrated that the developed electrothermal actuator is proper for a self-walker and soft robot which can be used in vacuum chamber.