The continuous and long-term measurement and monitoring of physiological signals such as electrocardiography (ECG) are very important for the early detection and treatment of heart disorders at an ...early stage prior to a serious condition occurring. The increasing demand for the continuous monitoring of the ECG signal needs the rapid development of wearable electronic technology. During wearable ECG monitoring, the electrodes are the main components that affect the signal quality and comfort of the user. This review assesses the application of textile electrodes for ECG monitoring from the fundamentals to the latest developments and prospects for their future fate. The fabrication techniques of textile electrodes and their performance in terms of skin–electrode contact impedance, motion artifacts and signal quality are also reviewed and discussed. Textile electrodes can be fabricated by integrating thin metal fiber during the manufacturing stage of textile products or by coating textiles with conductive materials like metal inks, carbon materials, or conductive polymers. The review also discusses how textile electrodes for ECG function via direct skin contact or via a non-contact capacitive coupling. Finally, the current intensive and promising research towards finding textile-based ECG electrodes with better comfort and signal quality in the fields of textile, material, medical and electrical engineering are presented as a perspective.
The conductive polymer complex poly (3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is the most explored conductive polymer for conductive textiles applications. Since PEDOT:PSS is ...readily available in water dispersion form, it is convenient for roll-to-roll processing which is compatible with the current textile processing applications. In this work, we have made a comprehensive review on the PEDOT:PSS-based conductive textiles, methods of application onto textiles and their applications. The conductivity of PEDOT:PSS can be enhanced by several orders of magnitude using processing agents. However, neat PEDOT:PSS lacks flexibility and strechability for wearable electronics applications. One way to improve the mechanical flexibility of conductive polymers is making a composite with commodity polymers such as polyurethane which have high flexibility and stretchability. The conductive polymer composites also increase attachment of the conductive polymer to the textile, thereby increasing durability to washing and mechanical actions. Pure PEDOT:PSS conductive fibers have been produced by solution spinning or electrospinning methods. Application of PEDOT:PSS can be carried out by polymerization of the monomer on the fabric, coating/dyeing and printing methods. PEDOT:PSS-based conductive textiles have been used for the development of sensors, actuators, antenna, interconnections, energy harvesting, and storage devices. In this review, the application methods of PEDOT:SS-based conductive polymers in/on to a textile substrate structure and their application thereof are discussed.
Electroencephalogram (EEG) is the biopotential recording of electrical signals generated by brain activity. It is useful for monitoring sleep quality and alertness, clinical applications, diagnosis, ...and treatment of patients with epilepsy, disease of Parkinson and other neurological disorders, as well as continuous monitoring of tiredness/alertness in the field. We provide a review of textile-based EEG. Most of the developed textile-based EEGs remain on shelves only as published research results due to a limitation of flexibility, stickability, and washability, although the respective authors of the works reported that signals were obtained comparable to standard EEG. In addition, nearly all published works were not quantitatively compared and contrasted with conventional wet electrodes to prove feasibility for the actual application. This scenario would probably continue to give a publication credit, but does not add to the growth of the specific field, unless otherwise new integration approaches and new conductive polymer composites are evolved to make the application of textile-based EEG happen for bio-potential monitoring.
Electronic yarns contain electronic components which are fully embedded into the conductive yarn’s structure before manufacturing smart textile garments or fabrics. To accept comprehensively the ...electronic textiles, it is essential to integrate the electronic components into/onto the conductive textile yarn without compromising the quality of the textile substrate. Therefore, one of the solutions is to create flexible and stretchable conductive yarn that contains a small surface-mounted electronic component embedded in the fibers of the conductive yarn. The purpose of this research work is to manufacture and subsequently evaluate the physical and electromechanical properties of amber strand (Toyobo’s p-phenylene benzobisoxazole fiber zylon) yarns with embedded surface-mounted device components. Using a benchtop reflow-soldering machine, the surface-mounted device component was successfully inserted into the amber strand conductive yarn. Then the developed electronic yarn was coated using thermoplastic polyurethane for encapsulation purposes. Furthermore, reliability tests of the electrical and mechanical properties of the electronic yarn (tensile strain and washing) were carried out. From the results it can be seen that the developed thermoplastic polyurethane encapsulated electronic yarn had a tensile strength of 37.38 N with a 4.1 mm extension. Furthermore, the relationship between the strain and washing action on the electrical resistance of the developed electronic yarn was experimentally investigated. The analytical finding shows that mechanical stress and laundry washing had a significant influence on the electrical resistance of the electronic yarn.
This research was aimed at obtaining a first estimation of the effect of turbulent vortices present in the relay nozzle jets of an air jet loom on the weft. To this end a large eddy simulation (LES) ...model was set up and validated capable of simulating a highly underexpanded jet up to a point sufficiently far from the nozzle exit such that flow features at the weft location could be analyzed. The quality of the LES was evaluated based on several quality criteria as well as by comparing the results with experiments and data from the literature. The results show that for a free jet substantial velocity fluctuations are present at a representative yarn location. By inserting a rigid cylinder at this location, the corresponding force fluctuations on a smooth yarn were also obtained. The research shows that the unsteadiness in the jet is quite substantial, as are the corresponding force fluctuations. These fluctuations could have a profound impact on the yarn motion and should at least be considered when using numerical tools to evaluate the forces on or the motion of a yarn acted on by a relay nozzle jet.
This paper presents a textile-based thermoelectric generator (T-TEG) with 105-pair thermocouples fabricated from carbon fibers as basic material. The carbon fiber used in this study was in a tow form ...which contains 3000 filaments. This tow was inserted into polyester fabric by hand to form a series of float yarns on the fabric. After acetone treatment, roughly every half of the floats on both sides of the fabric was covered by acrylic dispersion to resist nickel particles during electroplating in order to get a chain of carbon-nickel thermojunction. After the acrylic dispersion was completely polymerized, the sample was electroplated in the plating solution containing nickel acetate, boric acid, and sodium dodecyl sulfate. Subsequently, the sample was washed and dried. This T-TEG was fabricated on a small piece of fabric around 12 cm × 12 cm which contains 105-pair of carbon fiber and nickel-coated carbon fiber forming a thermopile. To study its electrical properties, this T-TEG was characterized to obtain the voltage-temperature curve, the voltage-current characteristic, the output power versus current and the maximum power versus temperature. Characterization results of this T-TEG show characteristics of a typical thermoelectric generator. Scanning electron micrograph images and EDS spectra were also examined to see the nickel deposition on the carbon fiber surface.
In the last three decades, the development of new kinds of textiles, so-called smart and interactive textiles, has continued unabated. Smart textile materials and their applications are set to ...drastically boom as the demand for these textiles has been increasing by the emergence of new fibers, new fabrics, and innovative processing technologies. Moreover, people are eagerly demanding washable, flexible, lightweight, and robust e-textiles. These features depend on the properties of the starting material, the post-treatment, and the integration techniques. In this work, a comprehensive review has been conducted on the integration techniques of conductive materials in and onto a textile structure. The review showed that an e-textile can be developed by applying a conductive component on the surface of a textile substrate via plating, printing, coating, and other surface techniques, or by producing a textile substrate from metals and inherently conductive polymers via the creation of fibers and construction of yarns and fabrics with these. In addition, conductive filament fibers or yarns can be also integrated into conventional textile substrates during the fabrication like braiding, weaving, and knitting or as a post-fabrication of the textile fabric via embroidering. Additionally, layer-by-layer 3D printing of the entire smart textile components is possible, and the concept of 4D could play a significant role in advancing the status of smart textiles to a new level.
In this paper a range of acid aqueous solutions are studied towards their suitability for developing chitosan nanofibres by electrospinning. It was found that parameters such as type of solvent, pH, ...concentration of chitosan, viscosity, charge density, applied voltage, solution flow rate, distance from nozzle tip to collector surface and time play a role in the characteristics of the obtained nanofibrous structures. After a preliminary study to select the most suitable composition of the chitosan containing solution (90% acetic acid), a detailed study was done to find the optimal conditions for chitosan nanofibrous structure development. Finally long-term experiments were performed, which showed that the formation of the nanofibrous structure distorts the electrical field.
In this work, we have successfully produced a conductive and stretchable knitted cotton fabric by screen printing of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and ...poly(dimethylsiloxane-b-ethylene oxide)(PDMS-b-PEO) conductive polymer composite. It was observed that the mechanical and electrical properties highly depend on the proportion of the polymers, which opens a new window to produce PEDOT:PSS-based conductive fabric with distinctive properties for different application areas. The bending length analysis proved that the flexural rigidity was lower with higher PDMS-b-PEO to PEDOT:PSS ratio while tensile strength was increased. The SEM test showed that the smoothness of the fabric was better when PDMS-b-PEO is added compared to PEDOT:PSS alone. Fabrics with electrical resistance from 24.8 to 90.8 kΩ/sq have been obtained by varying the PDMS-b-PEO to PEDOT:PSS ratio. Moreover, the resistance increased with extension and washing. However, the change in surface resistance drops linearly at higher PDMS-b-PEO to PEDOT:PSS ratio. The conductive fabrics were used to construct textile-based strain, moisture and biopotential sensors depending upon their respective surface resistance.
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