A review of connectors and joining technologies for electronic textiles

Electronic textiles, also known as smart textiles or smart fabrics, are one of the best form factors that enable electronics to be embedded in them, presenting physical flexibility and sizes that cannot be achieved with other existing electronic manufacturing techniques. As part of smart textiles, e-sensors for human movement monitoring have attracted tremendous interest from researchers in recent years. Although there have been outstanding developments, smart e-textile sensors still present significant challenges in sensitivity, accuracy, durability, and manufacturing efficiency. This study proposes a two-step approach (from structure layers and shape) to actively enhance the performance of e-textile strain sensors and improve manufacturing ability for the industry. Indeed, the fabricated strain sensors based on the silver paste/single-walled carbon nanotube (SWCNT) layers and buffer cutting lines have fast response time, low hysteresis, and are six times more sensitive than SWCNT sensors alone. The e-textile sensors are integrated on a glove for monitoring the angle of finger motions. Interestingly, by attaching the sensor to the skin of the neck, the pharynx motions when speaking, coughing, and swallowing exhibited obvious and consistent signals. This research highlights the effect of the shapes and structures of e-textile strain sensors in the operation of a wearable e-textile system. This work also is intended as a starting point that will shape the standardization of strain fabric sensors in different applications.

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An Investigation of the Physical and Electrical Properties of Knitted Electrodes When Subjected to Multi-Axial Compression and Abrasion

Proceedings ◽

10.3390/proceedings2021068002 ◽

2021 ◽

Vol 68 (1) ◽

pp. 2

Author(s):

Arash M. Shahidi ◽

Theodore Hughes-Riley ◽

Carlos Oliveira ◽

Tilak Dias

Keyword(s):

Heart Rate ◽

Electrical Properties ◽

Applied Load ◽

Pressure Sensors ◽

Electrical Performance ◽

Electronic Textiles ◽

Heart Rate Monitors ◽

Mechanical Loads ◽

And Performance ◽

Over Time

Knitted electrodes are a key component to many electronic textiles including sensing devices, such as pressure sensors and heart rate monitors; therefore, it is essential to assess the electrical performance of these knitted electrodes under different mechanical loads to understand their performance during use. The electrical properties of the electrodes could change while deforming, due to an applied load, which could occur in the uniaxial direction (while stretched) or multiaxial direction (while compressed). The properties and performance of the electrodes could also change over time when rubbed against another surface due to the frictional force and generated heat. This work investigates the behavior of a knitted electrode under different loading conditions and after multiple abrasion cycles.

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Electronic Textiles

Encyclopedia ◽

10.3390/encyclopedia1010013 ◽

2021 ◽

Vol 1 (1) ◽

pp. 115-130

Author(s):

Guido Ehrmann ◽

Andrea Ehrmann

Keyword(s):

Power Supply ◽

Sensor Data ◽

Electronic Textiles ◽

Sensors And Actuators ◽

External Communication ◽

Data Processor ◽

Temperature Strain

Electronic textiles belong to the broader range of smart (or “intelligent”) textiles. Their “smartness” is enabled by embedded or added electronics and allows the sensing of defined parameters of their environment as well as actuating according to these sensor data. For this purpose, different sensors (e.g., temperature, strain, light sensors) and actuators (e.g., LEDs or mechanical actuators) are embedded and connected with a power supply, a data processor, and internal/external communication.

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Thermoelectric Materials for Textile Applications

Molecules ◽

10.3390/molecules26113154 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3154

Author(s):

Kony Chatterjee ◽

Tushar K. Ghosh

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Seebeck Coefficient ◽

Thermoelectric Materials ◽

Figure Of Merit ◽

Inorganic Materials ◽

Peltier Effect ◽

Electronic Textiles ◽

Heating And Cooling ◽

Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

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Electronic Textiles Fabricated with Graphene Oxide-Coated Commercial Textiles

Coatings ◽

10.3390/coatings11050489 ◽

2021 ◽

Vol 11 (5) ◽

pp. 489

Author(s):

Hyun-Seok Jang ◽

Min-Soo Moon ◽

Byung-Hoon Kim

Keyword(s):

Heat Treatment ◽

Carbon Nanotubes ◽

Graphene Oxide ◽

Electronic Devices ◽

Electronic Textiles ◽

Axial Tension ◽

Coated Cotton

Demand for wearable and portable electronic devices has increased, raising interest in electronic textiles (e-textiles). E-textiles have been produced using various materials including carbon nanotubes, graphene, and graphene oxide. Among the materials in this minireview, we introduce e-textiles fabricated with graphene oxide (GO) coating, using commercial textiles. GO-coated cotton, nylon, polyester, and silk are reported. The GO-coated commercial textiles were reduced chemically and thermally. The maximum e-textile conductivity of about 10 S/cm was achieved in GO-coated silk. We also introduce an e-textile made of uncoated silk. The silk-based e-textiles were obtained using a simple heat treatment with axial tension. The conductivity of the e-textiles was over 100 S/cm.

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The impact of different proportions of knitting elements on the resistive properties of conductive fabrics

Textile Research Journal ◽

10.1177/0040517518758003 ◽

2018 ◽

Vol 89 (5) ◽

pp. 881-890 ◽

Cited By ~ 3

Author(s):

Su Liu ◽

Yanping Liu ◽

Li Li

Keyword(s):

Contact Resistance ◽

Reference Source ◽

Wearable Electronics ◽

Electronic Textiles ◽

Knitted Fabrics ◽

Conductive Yarns ◽

Key Factor ◽

Resistive Networks ◽

The Impact ◽

Resistive Property

Conductive yarn is the key factor in fabricating electronic textiles. Generally, three basic fabric production methods (knit, woven, and non-woven) combined with two finishing processes (embroidery and print) are adopted to embed conductive yarns into fabrics to achieve flexible electronic textiles. Conductive yarns with knit structure are the most flexible and effective form of electronic textiles. Electronic textiles present many advantages over conventional electronics. However, in the process of commercialization of conductive knitted fabrics, it is a great challenge to control the complicated resistive networks in conductive knitted fabrics for the purpose of cost saving and good esthetics. The resistive networks in conductive knitted fabrics contain length-related resistance and contact resistance. The physical forms of conductive yarns in different fabrication structures can be very different and, thus, the contact resistance varies greatly in different fabrics. So far, study of controlling the resistive property of conductive fabrics has not been conducted. Therefore, establishing a systematic method for the industry as a reference source to produce wearable electronics is in great demand. During the industrialization of conductive knitted fabrics, engineers can estimate the resistive property of the fabric in advance, which makes the production process more effective and cost efficient. What is more, the resistive distribution in the same area of knitted fabrics can be fully controlled.

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