Printed Nanocarbon Heaters for Stretchable Sport and Leisure Garments

Abstract

The ability to maintain body temperature has been shown to bring about improvements in sporting performance. However, current solutions are limited with regards to flexibility, heating uniformity and robustness. An innovative screen-printed Nanocarbon heater is demonstrated which is robust to bending, folding, tensile extensions of up to 20% and machine washing. This combination of ink and substrate enables the heated garments to safely flex without impeding the wearer. It is capable of producing uniform heating over a 15 × 4 cm area using a conductive ink based on a blend of Graphite Nanoplatelets and Carbon Black. This can be attributed to the low roughness of the conductive carbon coating, the uniform distribution and good interconnection of the carbon particles. The heaters have a low thermal inertia, producing a rapid temperature response at low voltages, reaching equilibrium temperatures within 120 s of being switched on. The heaters reached the 40 °C required for wearable heating applications within 20 s at 12 Volts. Screen printing was demonstrated to be an effective method of controlling the printed layer thickness with good interlayer adhesion and contact for multiple printed layers. This can be used to regulate their electrical properties and hence adjust the heater performance.

Future Thread: Printing Electronics on Fibers

“…The temporal response of the microheater measured for a period of 35 s of heating followed by a period of 25 s of cooling down, which is shown in Figure c. The microheater exhibited a rapid electrothermal response, through rising to 66% of the saturation temperature within just 5 s. , Such a brisk actuation is important, for instance, for a thermal sensor based on transient plane source (TPS) measurements . The steady state temperature of the heater has been achieved within 18 s, which can be appealing for wearable applications. , …”

Flexible Coated Conductive Textiles as Ohmic Heaters in Car Seats

“…Printed heaters have used tiny carbon heating elements between silver conductors to get around the large sheet resistance of carbon sheets [13]. GNP-only inks are ideal for wearable heating applications, and rigid substrates have been employed in printed heating systems because of their high resistance [14]. The effectiveness of the heat pumps during tensile extensions had not traditionally been evaluated, notwithstanding flex testing.…”