electronics Article Electrical Characterization of Conductive Threads for Textile Electronics Adrian K. Stavrakis * , Mitar Simi´ c and Goran M. Stojanovi´ c   Citation: Stavrakis, A.K.; Simi´ c, M.; Stojanovi´ c, G.M. Electrical Characterization of Conductive Threads for Textile Electronics. Electronics 2021, 10, 967. https:// doi.org/10.3390/electronics10080967 Academic Editors: Melina P. Ioannidou, Ioannis O. Vardiambasis, Nikolaos V. Kantartzis and Hirokazu Kobayashi Received: 25 February 2021 Accepted: 7 April 2021 Published: 19 April 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovi´ ca 6, 21000 Novi Sad, Serbia; mitar.simic@uns.ac.rs (M.S.); sgoran@uns.ac.rs (G.M.S.) * Correspondence: sadrian@uns.ac.rs; Tel.: +381-638849971 Abstract: In recent years, advancements in technology are constantly driving the miniaturization of electronic devices, not only in the renowned domain of Internet-of-Things but also in other fields such as that of flexible and textile electronics. As the latter forms a great ecosystem for new devices, that could be functional such as heating garments or sensory, many suppliers have already started producing and bringing to market conductive threads that can be used by researchers and the mass public for their work. However, to date, no extensive characterization has been carried out with respect to the electrical performance of such threads and that is what this article is aiming to amend. Four commercially available threads by two different suppliers were put under test, to establish their limitations in terms of maximum power handling, both continuous and instantaneous. They were subsequently examined at a microscopic scale as well, to verify any potential caveats in their design, and any hidden limitations. A preliminary profile for each of the four threads was successfully established. Keywords: conductive threads; textile electronics; characterization; electrical performance; wear- able electronics 1. Introduction In the last decade, growing interest can be found in the domain of stretchable electronic systems. This field is so attractive to researchers and market players not only because of the unique opportunities to use a multitude of materials such as paper, textile, or plastics, but also because it allows for the creation of devices sporting excellent comfort, compatibility, fit, and deformation [1,2]. Even though this research area can still be considered in its infancy, work has been presented where sensing elements, new production ideas, and design, have been seamlessly brought together to build wearables that do not alienate their user and blend easily into their daily clothing [3–6]. As such, devices require materials that need to exceed the mechanical properties of thin films, commonly found in printed circuit board design, via an aspiring new field using the integration of textiles, in particular, conductive threads that enable the creation of the so-called e-textile domain [7,8]. There should be no misconception that conductive threads are the only solution to creating e-textiles, although there are alternatives such as the utilization of metallic interconnects through lithographic processes, screen printing [9], micro dispensing [10], or even inkjet printing [11–14]. However, such approaches, combined with the extreme and uneven roughness of woven materials, wicking phenomena, and abrasion due to washing chemicals, even though good at conserving materials, may not be the most suitable candidates for creating long-lasting e-textiles. Alternatively, if the added functionality of the textile or garment is provided by its very own threads [15], it is overall expected to have a much longer useable lifetime. This idea of creating conductive fibers that can create threads is already well researched. Silver has been used to coat nylon and cotton threads at varying densities in [16], as well as Electronics 2021, 10, 967. https://doi.org/10.3390/electronics10080967 https://www.mdpi.com/journal/electronics