Electronic textiles categories

Transistors as the basic and crucial component for electronic circuits have been vigorously studied since 1947. The essential function of a transistor comes from its ability to control a larger signal by an apphed small signal between one pair of its terminals. This property makes the transistor as an amplifier or switch. According to the mechanism of the generation of carriers in the channel, transistors can be divided into three categories bipolar junction transistor, field-effect transistor, and electrochemical transistor. In electronic textile applications, the EET and ECT are employed to realize fibrous transistors. 

FRs are chemicals that can inhibit ignition and/or reduce the burning rate of a product. These are often used by manufacturers to help them meet fire safety standards set down by law for products such as electrical equipment, furnishings, and vehicles. These compounds are added to polymers, paint, textiles, and other materials to improve their fireproof properties. The main applications are in plastic housings of electronic products such as TV sets and computers, car parts, circuit boards, electric components, and cables. There are currently over 100 different substances used as FRs and these can be classihed in four categories (Figure 31.1) ... 

Among the various categories of smart textiles and flexible materials, which include optically, mechanically, chemically, electrically, and thermally activated substances/ stmctures (Tao, 2001), several have shown large opportunities of applications in PPE. This includes wearable electronics, for example, physiological condition, temperature, and humidity sensors, power and data transmitters, and end-of-life indicators, which are the subject of the next chapter of this book. Various types of smart flexible materials have also found their way into PPE, for instance, as responsive barriers, self-decontaminating membranes, thermoregulating layers, and shock-absorbing patches. 

The addition of wearable devices should not impede the comfort of the PPE or the mobility of the wearer. Therefore, a high level of integration is expected but is not always met. Indeed, the level of intimacy between the electronic components and the textile substrate can be classified in three categories ... 

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. 

Structurally, textile electronic circuits can be classified into two categories conventional electronic component implemented on fabric-based flexible planar circuit board (PCB) and intrinsic functional fiber/yarn-based circuit. 

The incorporation of flame retardants into plastics, textiles, electronic equipment (e.g. printed circuit boards) and other materials is big business, and demand in the US reached approximately US 1.3 billion in 2008. The chart on the right shows the split between the three main categories of flame retardants in the US in 2003. A range of brominated organics is used commercially, the most important being ... 

Thus in an elementary fashion and if we consider the three broad materials categories of insulators, semiconductors and conductors (such as metals), CPs differ from typical everyday organic polymers such as poly (ethylene), poly(vinylidene chloride) ("Saran" wrap), polyesters (used in textiles) and other everyday plastics, which are generally highly insulating, in that tlieir unique 7r-electron properties impart electrical conductivity at room temperature, and many other derivative and interesting properties discussed at length in this book, on oxidation or reduction. 

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