• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.1
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• pp.46-55
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• 2021

Seam puckering and the seam strength of conductive threads used to produce smart clothing were analyzed according to stitching methods and fabrics. Samples were prepared in a lock stitch and zigzag stitch on plain woven and jersey knit fabric, using one type of polyester sewing thread and three types of commercial conductive threads that consisted of two types of stainless-steel conductive threads (TST and MST) and one type of silver conductive thread (SSV). Seam pucker percentages, shapes, and seam strength were measured. On plain woven fabric as well as jersey knit fabric, three-ply TST and MST showed a higher SP percentage compared to a polyester sewing thread. Meanwhile, single-ply SSV showed the lowest SP percentage. In addition, the SP percentage of the zigzag stitch decreased along the weft and course directions of the fabric, and decreased significantly as the number of fabric layers increased. Moreover, there was a marked tendency for a higher SP percentage in jersey knit fabric compared to plain woven fabric, and the two-dimensional cross-section waveforms of stitches obtained using three-dimensional data that showed increased irregular waveforms and peaks in the zigzag stitch. There were no correlations between seam strength and tensile strength.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.3
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• pp.474-485
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• 2018

Smart sensors and connected devices have changed the concept of garments along with IT technology convergent garments that transform the performance of basic functions. Various types of products have been researched and developed due to the increased interest in smart clothing; in addition, studies based on physical and mechanical properties have also been actively studied to improve accuracy and reliability. This study represents a basic study for the development of smart textiles based on motion recognition for the surfing practice of beginners interested in IT convergence type. A physical durability evaluation of conductive yarn according to sewing method was later carried out. This study is a conditional specimen sewn with cotton lower thread and 100mm pattern length based on the results of previous studies. The durability of the conductive yarn according to the sewing method was evaluated according to the sewing method. Durability was evaluated by two kinds of repeated strain and abrasion tests. The specimen with applied cotton in a lower thread zigzag pattern 2mm stitch size 100mm stitch length was shown to have the most suitable durability for smart textile.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.1-6
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• 2008

A wearable T-matching dipole UHF RFID tag antenna has been designed using conductive electro-thread. The conductivity of the electro-thread has been measured depending on the number of twisted thread. The measured conductivity has been used for simulation to have accurate simulation results. The flexible electro-thread or fabric has been used for fabricating the antenna instead of using copper tape since the electro-thread is more flexible and wearable than copper tape. The return loss and reading range of the fabricated electro-thread UHF RFID tag antennas have been tested. The reading range is approximately 2.4 m.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.4
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• pp.674-684
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• 2021

Recent advances in electronic technology have engendered a need for research on the use of smart materials in clothing. Electro-conductive fibers are expected to be a crucial element of wearable devices. Therefore, in this study, we have attempted to develop electro-conductive threads and cables using silver nanowires. Based on the characteristics of silver nanowire, in which electro-conductivity can be imparted via heat treatment, we prepared conductive threads by coating nylon yarn with silver nanowires and curing at temperatures of 140℃, 150℃, and 160℃. Conductive threads cured at 140℃ had the highest conductivity, followed by threads cured at 160℃ and 150℃ respectively. The order of the electrical conductivity of the threads after tensile testing was consistent with the original order of the conductivity of the threads. When we evaluated the sensing performance of electro-conductive cables fabricated from these threads, the cables manufactured from threads cured at 140℃ and 160℃ were found to function normally within temperature and humidity sensors. All the cables operated normally in illuminance and electrocardiogram sensors. Thus, we believe that threads made of silver nanowire have sufficient electrical conductivity to be utilized as wearable sensors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.10-15
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• 2017

Research interest has strongly focused on developing a method for effectively transmitting bio-signals over a distance using a wireless wearable device. In this paper, we describe a procedure for the design and fabrication of a wearable antenna based on embroidering conductive threads to clothing capable of transmitting electrocardiogram signals. 3D electromagnetic simulation software and embroidery software were used to design and fabricate the conductive thread-based antenna, respectively. The measurement results show that the reflection coefficient of the fabricated antenna prototype exhibits excellent antenna impedance matching characteristics of less than -10dB in the Zigbee 2.4GHz frequency band. We also verified that the electrocardiogram data could be effectively received and monitored in real-time by a receiver 220m away from the transmitter.

• Journal of Sensor Science and Technology
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• v.30 no.2
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• pp.67-70
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• 2021

A new button-shaped electrical device was developed for a smart fabric. This electric button can be sewn anywhere on the garment, similar to a traditional button fastener. t not only performs a decorative function but also makes the fabric suitable for use in Internet of Things (IoT) applications. It has metallic through-holes such that it can be fastened onto a fabric by conductive sewing threads. When threaded through metallic holes, the button can communicate with the external device by transmitting and receiving data. In addition, it adds specific functions by stacking a detachable application layer on the base layer. It is robust to frequent washing, and thus has excellent repeatability for use as an IoT device. The feasibility of the electric button was successfully demonstrated by its ability to identify the physical activities of walking and running, monitoring ambient temperature, and turning on LED lights.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1210-1215
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• 2016

• Journal of Fashion Business
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• v.21 no.6
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• pp.16-30
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• 2017

Currently, e-textile market is rapidly expanding and the emerging area of e-textiles requires electrically conductive threads for diverse applications, including wearable innovative e-textiles that can transmit/receive and display data with a variety of functions. This study introduces hybrid nano-structures which may help increase the conductivity of the textile threads for use in wearable and flexible smart apparels. For this aim, Ag was selected as a conductive material, and yarn treatment was implemented where silver nanowire (AgNW) and graphene flake (GF) hybrid structures overcome the limitations of the AgNW alone. The yarn treatment includes several treatment conditions, e.g., annealing temperature, annealing time, binder material such as polyurethane (PU), coating time, in order to search for the optimum method to form stable conductive nano-scale composite materials as thin film on the surface of textile yarns. Treatedyarns showed improved electrical resistance readings. The functionality of the spandex yarn as a stretchable conductive thread was also demonstrated. When the yarn specimens were treated with colloid of AgNW/GF, relatively good electrical conductivity value was obtained. During the extension and recovery cycles of the treated yarns, the initial resistance values did not deteriorate significantly, since the network of nanowire structure with the support of GF and polyurethane stayed flexible and stable. Through this research, it was found that when one-dimensional structure of AgNW and two-dimensional structure of GF were mixed as colloids and treated on the surface of textile yarns, flexible and stretchable electrical conductor could be formed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1071-1076
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• 2009

A wearable embroidery 'ㅂ' character shape UHF RFID tag antenna has been designed using conductive electro-thread. After testing characteristics of various electro-threads, the embroidery tag, with a T-matching structure, has been designed on a cloth with 200D(denier) electro-thread which performs electrically better. The embroidery tag on a piece of fabric or clothes made with the flexible electro-thread is a wearable tag and possible to be recognized by an RFID system. The conductivity of different deniers of electro-threads has been measured. The measured conductivity has been used for simulation and fabrication to have accurate simulation results. To verify the characteristics of the tag antenna, the return loss and reading range of the fabricated embroidery electro-thread UHF RFID tag antenna have been tested. The reading range is approximately 1.52 m.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.49-56
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• 2021

In this study, we investigated the necessary mechanical properties of conductive multifilament yarns for fabricating the electrodes of biosignal measurement pressure and stretch textile sensors using embroidery. When electrodes and circuits for smart wearable products are produced through the embroidery process using conductive multifilament yarns, unnecessary material loss is minimized, and complex electrode shapes or circuit designs can be produced without additional processes using a computer embroidering machine. However, because ordinary missionary threads cannot overcome the stress in the embroidery process and yarn cutting occurs, herein, we analyzed the S-S curve, thickness, and twist structure, which are three types of silver-coated multifilament yarns, and measured the stress in the thread of the embroidery simultaneously. Thus, the required mechanical properties of the yarns in the embroidery process were analyzed. In the actual sample production, cutting occurred in silver-coated multifilament rather than silver-coated polyamide/polyester, which showed the lowest S-S curve. In the embroidery process, the twist was unwound through repetitive vertical movement. Further, we fabricated a piezoresistive pressure/tension sensor to measure gauge factor, which is an index for measuring biological signals. We confirmed that the sensor can be applied to the fabrication of embroidery electrodes, which is an important process in the mass production of smart wearable products.