Printed Nanocarbon Heaters for Stretchable Sport and Leisure Garments.

Andrew Claypole,Liam Kilduff,David Gethin,James Claypole,Tim Claypole,Neil Bezodis

doi:10.3390/ma15020573

Andrew Claypole, Liam Kilduff + Show 4 more

Open Access

https://doi.org/10.3390/ma15020573

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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.

Highlights

Flexible electrothermal heaters can be integrated into clothing to create wearable warming garments [1,2,3] and the ability to maintain body temperature has been shown to bring about improvements in sporting performance [4,5]
The effect of using higher heated garment temperatures was examined by using water perfused trousers at 43 ◦C and this virtually eliminated the drop in thigh muscle temperature during a 15-min period of inactivity, proving optimised heating will maintain muscle temperature
The available wearable heating technology based on metal wire heaters have poor flexibility, suffer from oxidative corrosion, provide non-uniform heating, have low heating efficiency, limited heating areas and have a short lifetime on account of broken wires [1,2,7]

Summary

Introduction

Flexible electrothermal heaters can be integrated into clothing to create wearable warming garments [1,2,3] and the ability to maintain body temperature has been shown to bring about improvements in sporting performance [4,5]. The ability to print a large-area, stretchable and flexible nanocarbon heater using low-cost inks and scalable techniques to create a wearable heating garment would be a disruptive technology. The ultimate objective of this research was to create a printed nanocarbon heater capable of achieving temperatures of 40 ◦C and to maintain a uniform temperature output when flexed and stretched Delivery of this objective has required the development of carbon inks that possess appropriate mechanical and electrical properties together with their processability will be considered in the following paragraphs. A large-area, screen-printed nanocarbon heater is demonstrated using a highly conductive nanocarbon ink, capable of producing the 40 ◦C required for wearable heating, while showing good robustness to flexing, compressing, tensile extensions of up to 20% and machine washing. TThhee ccaarrbboonn aanndd ssiillvveerr iinnkkss hhaadd ssiimmiillaarr ffiillmm llaayyeerr tthhiicckknneesssseessaatt88.8.877aanndd88.1.818μμmmrersepsepcetcivtievlyel(yTa(Tbalebl1e),1i)r,reirsrpeescpteivcetivoef ionfkifnokrmfourlmatuiolan-, stihoonw, sinhgowgoinogd gagoroedemagernetewmiethntthweitlihtetrhaetulirteerwahtuicrhe wstahtiecshtshtaattethsethscartetehnepsacrraemeneptearrsa, mnaemteerlsy, screen emulsion and the mesh are the major factors in controlling the print thickness [24,29]

Carbon 2 Carbon 1 Silver 2 Silver

Findings

Carbon 1 Silver