Conductive textiles threads

Figure 10.2 Comparison between differrait conductive textiles (1) embedded metal threads (Ouyang and Chappell, 2008) (2) metallized textUes/fabrics (Bashir et al., 2009) (3) conductive threads (Kim et al., 2008) (4) commercial conductive textiles (www.lessemf.com/ fabric.html) and (5) embroidered metal-coated polymer fibers (E-fibers) (Wang et al., 2012b).

Atwa, Y., Maheshwari, N., Goldthorpe, LA., 2015. Silver nanowire coated threads for electrically conductive textiles. 1. Mater. Chem. C3, 3908. 

Traditional appHcations for latices are adhesives, binders for fibers and particulate matter, protective and decorative coatings (qv), dipped goods, foam, paper coatings, backings for carpet and upholstery, modifiers for bitumens and concrete, and thread and textile modifiers. More recent appHcations include biomedical appHcations as protein immobilizers, visual detectors in immunoassays (qv), as release agents, in electronic appHcations as photoresists for circuit boards, in batteries (qv), conductive paint, copy machines, and as key components in molecular electronic devices. 

Carbon fiber electrode - Edison produced the first carbon fibers by carbonization of cotton threads in 1879. Today polyacrylonitrile (as well as Rayon and various other organic precursors) is the most common precursor for carbon fiber formation [i]. Carbonization of polyacrylonitrile is carried out at 1500 °C to give highly electrically conducting fibers with 5-10 pm diameter. Fibers carbonized at up to 2500 °C are more graphitic with a carbon content of >99%. Carbon fiber-based materials have found many applications due to their exceptionally high tensile strength. In electrochemistry carbon fiber -> micro electrodes are very important in analytical detection [ii] and for in vivo electrochemical studies [iii]. Carbon fiber textiles are employed in - carbon felt electrodes. 

CONDUCTIVE THREAD MATERIALS FOR THE INTEGRATION OF TEXTILE SENSORS AND ACTUATORS... 

The development of special conductive thread materials for the creation of textile sensor areas and bus-structures are the main topics of the TTTV Greiz in the CONTEXT project. The realisation occurs by the creation of different woven multi-Iayw-structures. So it is for example possible to create textile cqtacitors, winch can be as a sensor area or insulated textile bus-structures. 

E-textiles circuits can be constmcted using conductive threads/yams by embroidery. 

To integrate the ultrasonic sensor to textile structures as well as to form electric circuits in the stmcmres, silver-plated nylon yarn with a linear resistance of <50 n/m and with a yam count of 312/34f x 4 dtex is used. To prevent formation of short circuits in the textile-based electric circuit, conductive yams are hidden in the stmcture. A fabric stmcmre is considered as a double-woven fabric, and conductive yarns are placed in the middle layer of the stmcmre. The set of warp yams of the upper layer are linked to the set of weft yarns from the bottom layer, and thus the two layers are held together. A four-harness satin weave is chosen for both layers. Fig. 3.2 shows the diagram representing the drawdown, threading, and lift plan of the double-woven cloth together with the 3D-graphical representation of the woven fabric stmcture. 

Another strategy has to be chosen. This is to let the piezofiber (ie, the conductive core with high-density polyethylene (Aspun 6835A, Dow, USA) and carbon black (Ketjenblack EC-600JD Akzo Nobel, the Netherlands) and the piezoelectric sheath with PVDE (Solef 1006, Solvay Solexis, Italy)) mecharucaUy come into close proximity with a conductive thread. Here we take a thread from Class El above, Shieldex (Statex, Germany, silver-coated polyamide). By this we form a textile variant of the triad with the conductive carbon black core as the inner electrode, PVDF sheath as the active layer, and the Shieldex as the outer electrode. 

E-broidery, embroidery with conducting threads, is described by Post (1996) and Post et al. (2000). The sewability of various electrically conducting yams is compared. Stainless steel threads have advantages because of their resistance to corrosion, biological inertness, availability in textile form and low cost. However, it is difficult to attach them to existing components. Composite yams made from steel and polyester can be sewn by machine (Post et al., 2000). 

Electrically conducting threads were manufactured in antiquity before electricity was discovered. In modem times, metal wires, metal-wrapped yams, metal-coated yams, inherently conductive polymers and other technologies have been employed to confer electrically conducting pathways to textiles. Originally, conventional electrical wires were used, but then more sophisticated approaches were adopted. With the high growth in wearable devices and electronic textiles in particular, there will be an added impetus for the development of electrically conducting pathways with properties more in line with conventional fibres and yams. 

After determining the sensor concept, the physical parameter for measuring with the sensor must be set up. Textile sensors that are part of the textile itself must react to all different kinds of forces. Therefore, various sensor concepts, which rely on physical, chemical and thermal parameters, are suitable for application. They help detect forces, displacements, thermal energy, humidity, chemicals, UV radiatimi and other actions. Then, the received information from the environment can be transformed into electric signals. In this third step, one must decide where to place the conductive threads between the nonconductive one, and which manufacturing technology is suitable for the product requirements. 

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