E-textiles circuits

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

Scientist of NASA Johnson Space Center (NASA Tech Briefs, 2008) demonstrated flexible, electrically conductive patterns on textile substrate for many applications including high-speed digital circuits, antennas, and RF circuits. E-textile circuits... 

E-textiles circuits (Courtesy of Bally Ribbon Mills NASA Tech Briefs, 2008) can be made by selecting woven conductive and nonconductive fabric layers. The woven conductive layer should have established surface conductivity specifications. 

These antennas can be used on a variety of projects to realize battlefield wireless anteimas or to incorporate antennas into airframes or vehicles. E-textile antennas could be incorporated into composite structures during the manufacturing process. The use of composite antenna encapsulation allows radar and communications anteimas to be incorporated into airframes and ship hulls in a manner not before possible. This advanced E-textile-based antenna process can find application in the incorporation of antennas and other microwave circuits into UAVs and vehicles. Government and commercial applications of this technology include the incorporation of these wireless antennas into uniforms, truck covers, tents, and seats. They can stitch onto carpets, ceiling tiles, and headliners as well as tapestries and many other textile products that surround us every day. 

The transistor as a component of the e-textile plays a crucial role in the textile electronic circuit. The existing fibrous transistors can be divided into two categories wire thin film transistors (WTFTs Lee and Subramanian, 2003 Maccioni et al., 2006 Locci et al., 2007) and wire electrochemical transistors (WECTs Hamedi et al., 2007 De Rossi, 2007 Tao et al., 2011). WTFT, also called WFET, is based on the field-effect transistor (FET) technology and WECT is based on electrochemical technology. With the help of these transistors, the textile electronic circuit can be achieved without loss of mechanical properties such as flexibility or softness. 

Bonderover, E., Wagner, S., 2004. A woven inverter circuit for e-textile apphcations. Electron Device Letters, IEEE 25, 295—297. 

Developing an ad hoc structure, they were able to design a custom textile circuit, as shown in Fig. 4.12B. Generally, the fabric has a regular stmcture (warp and weft), however in microscale it is not possible to obtain a geometric repeatability of the position of the contact point between the conductive fibers, as shown in Fig. 4.13. This issue, appreciable with a common optical microscope tool, becomes critical when an electrical component needs to be soldered on the e-textile. 

The primary use of TBBPA is as a flame retardant in epoxy resin circuit boards and in electronic enclosures made of polycarbonate-acrylonitrile-butadiene-styrene (PC-ABS). Other applications of TBBPA include its use as a flame retardant for plastics, paper, and textiles as a plasticizer in adhesives and coatings and as a chemical intermediate for the synthesis of other flame retardants (e.g., TBBPA allyl ether). It is also been applied to carpeting and office furniture as a flame retardant. 

The radioelectric properties of two composites based on polyaniline impregnated glass textiles with different conductivities have been characterised. Changes of (fi. e") with frequency are shown in Figure 8.41. A dependence quite different from those already presented is observed. Indeed, for both conductivities, log e" decreases linearly with log/ with a slope close to unity, e.g., 0.7 and 0.8. This behaviour, independent of conductivity, is representative of a purely resistive material. The electrical equivalent circuit was found to be a resistance in parallel with a capacitance [84,86]. 

The excellent electrical insulation property of E-glass has found many applications in this field. Fabrics made of textile glass yarn is the backbone of the printed circuit board of the modern electronic industry. Polybutene terephthalate, polyphenylene sulfide, and liquid crystal polymer reinforced with chopped glass fiber are also widely molded into electronic components (23). 

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