Smart textiles (also known as intelligent textiles, electronic textiles, or e-textiles) have attracted considerable attention for their ability to extend the functionality and utility of common fabrics. Smart textiles are defined as textile products, such as fibers, filaments, and yarns, together with woven, knitted, or non-woven structures, which can interact with the environment/user and provide some other functionality.¹ Most smart textiles in existence today include a variety of embedded electronic components (such as electronic chipsets, sensors, wires, batteries, etc.) that are rigid and generally incompatible with standard apparel. The rigid components introduce wearability and reliability problems into these garments. Recent efforts have been applied toward developing more flexible electronic components.² These include conductive fibers prepared by wet spinning of polyaniline,³ energy textiles prepared by dipping into carbon nanotube solutions,⁴ flexible piezoelectric nanogenerators prepared by synthesizing ZnO nanowires on carbon fibers and paper,⁵ stretchable conductive textiles prepared from composite films of carbon nanotubes and silver,⁶ and organic transistors prepared by applying a polymer semiconductor coating on top of fibers.⁷

The supercapacitors for smart textiles have been studied by M. Skorobogatiy et al², Y. Cui et al⁴, and S. Thomas et al⁸. A highly flexible, conductive polymer-based fiber supercapacitors has been studied by M. Skorobogatiy et al² and S. Thomas et al⁸. Because these methods are very complex, Y. Cui et al⁴ proposed simple method to fabricate the textile supercapacitor by dipping textile into the carbon nanotubes (CNT) solution. CNT can act simultaneously as electrodes and current collectors due to their relatively high conductivity compared to other electrode materials.⁴ The use of CNT as current collectors, however, is limited due to the relatively high resistivity of CNT compared to metal-based current collectors. Other weaknesses of these devices include the three-dimensional (3D) sandwich structure employed in traditional energy devices. A 3D sandwich structure presents several drawbacks when included in integrated circuits compared to two-dimensional (2D) planar structures because a 2D planar structure can be simultaneously prepared with other circuit units.

In this study, we propose a method that overcomes the drawbacks of CNT-based energy textiles, such as their low conductivity and the 3D sandwich structure, by using silver (Ag) nanoparticles (NP) ink, an intense pulsed light (IPL) sintering system, and a simple spray patterning system. The Ag NP current collectors displayed a higher conductivity than the CNT current collectors. However, compared to CNT current collectors, the heat treatment temperature of Ag NP current collectors is too high to be used on textile substrate. (i.e., a temperature of 150 °C or more which causes heat damage to the textile substrate) IPL sintering systems can reduce the sintering temperature of Ag NP and prevent thermal damage to textiles during the Ag NP sintering process. The spray patterning technique is very useful for preparing printed electronics because it is a very simple, fast, and low-cost process. We propose a simple combination system for overcoming the problems associated with CNT current collectors by using Ag NP, an IPL sintering system, and a spray patterning system.⁹

Acknowledgments

This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant NRF-2016M1A2A2940915/2015K000217/10052802/CAP-15-04-KITECH/NK202C/NK202F/N0002310).

References

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³ D. Bowman, B. R. Mattes, Synthetic Met. 154, 29 (2005).

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⁵ Q. Liao, Z. Zhang, X. Zhang, M. Mohr, Y. Zhang, H. –J. Fecht, Nano Research 7, 917 (2014).

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