The Emergence of E-Textiles

Tracing the roots of mechanical computing to industrial weaving and looking towards how computers themselves may be woven in the future. A video of this presentation is available at https://www.youtube.com/watch?v=c39EOdxLoXI&feature=youtu.be

Transcript

1. rebecca.stewart@qmul.ac.uk The Emergence of E-Textiles Becky Stewart
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4. rebecca.stewart@qmul.ac.uk https://www.flickr.com/photos/cogdog/4905713747
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16. rebecca.stewart@qmul.ac.uk http://elliotts.net/content/images/thumbs/0000518_magnashield-kevlar-glove-woven-palm-and-felt-back_600.jpeg
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19. rebecca.stewart@qmul.ac.uk Metal threads: the historical development by Anna Karatazni [4] which were produced by drawing a metal rod through progressively smaller holes, a technique also employed by the goldsmiths”. However, she suggests that the wires used at Birka were imported from Byzantium via Russia. Járó (1990a, 43) also claims that other early examples of wires found in Western European textiles might have been imported from the East. Geijer (1983, 89) has also identified a rare type of thread among the samples examined from Birka, the spiral wire, which is a kind of tir-tir thread. This is a fine wire wound tightly around a core thread and is not commonly found in textile works of that period. The spiral wires found are made either of gold or of silver. According to her this unusual technique was known to the Lapps of Northern Sweden, who used it in their dresses, but their wires were made of pewter. However, trade contacts between the Lapps and merchants from Birka brought the technique into the Viking areas, where it was further developed using precious metals in their production. a b c Fig. 2. OM images of file threads a) gold b) silver (tarnished) and c) copper/brass (a) scale 4mm and b,c ) mag. X40) Silver based threads Threads made of silver or silver alloys were also used for the decoration of textiles (Fig 2b). According to Járó (2003, 166) silver threads were probably used by the Greeks to decorate textiles, but she does not give any date, while the Romans are said to have used them in the 1st century AD. However, the first dated examples come again from Birka and are dated to the 9th/10th century (Geijer 1983, 89-96). Gilt silver threads, made from a strip wound around a fibrous core, were already in [2] 1961; Járó and Tóth 1991; Stodulski et al. 1985). Based on their morphological characteristics the combined threads can be (Fig. 1): x Thin strips of gold or silver wound around a silk or fine linen thread. x Gold or silver wire which is wound creating a spiral, also known by the Turkish term tir-tir. x Gilt membrane strips. In this case very fine gold sheets are beaten on to an animal membrane, cut into lamellae (strips) and wound around a core yarn. x Gilt leather or gilt paper strips. These are narrow strips of gilt leather or paper produced by the same method as the gilt membrane strips. a c b d e f Fig. 1: Types of metal threads: a) metal strip, b) wire, c) strip wound around a silk yarn, filé; d) spiral wire, tir-tir; e) gilt membrane strip spun around a silk yarn, and f) gilt leather strip wound around a silk yarn. OM images, (mag. x40). The metals mainly used are gold, silver and copper, either alone or combined; while zinc occurred frequently as a component of copper alloys. The organic supporting material could be cellulose based (paper) or protein based (leather, parchment and animal gut). The fibrous core could be a protein-based fibre such as silk, wool or hair, although so far wool has not been identified. The cellulose-based fibre could be linen,
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21. rebecca.stewart@qmul.ac.uk “[The Analytical Engine] might act upon other things besides number, were objects found whose mutual fundamental relations could be expressed by those of the abstract science of operations, and which should be also susceptible of adaptations to the action of the operating notation and mechanism of the engine. Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent.” Ada Lovelace
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29. rebecca.stewart@qmul.ac.uk Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2912-1309 Vol. 1 Issue 1, November - 2015 silicon carbide powder were mixed with 10% platinum catalyst. After stirring the mixture carefully for three minutes, the solution was left in a vacuum chamber for five minutes to prevent air bubble formation in the mould. The mixture was then poured inside the clay walls and left to harden. Fig. 1: The three stages of the FET process: Interconnect formation (a), Encapsulation (b) and covering (c). The thermistor was positioned inside the micro- mould and 90μg of solder paste was deposited on each of the solder pads of the thermistor using a controlled solder dispenser (Ultimus™ I, Nordson EFD, RI, USA). The fine copper wire was then laid unbroken across the solder pads before curing the solder using the reflow work station as detailed previously (The end result is shown in Figure 1a). After completion of the soldering process the short circuit created by the length of copper wire remaining between the two solder pads was removed with a was used as a glue to stick the thermistor chip on to the silicone sheet. Thereafter, the mixture was hardened using a hot air gun (HL 1810 S, STEINEL, UK). As with the silicone and silicon carbide mixture, the solution of GPR mixed with 2% methyl ethyl ketone peroxide as a catalyst, was left in a vacuum chamber for five minutes and then poured inside the silicone walls. Two cymbal yarn tensioners were welded on either side of an aluminium rod to hold and control the copper wire during the soldering process. The two moulds were positioned between the two tensioners. To ensure that the copper wire is in contact with the micro-chip when it is positioned in the mould the two halves were fixed on to the aluminium rod at equal height. The copper wire is positioned in the tensioners as shown in Figure 2. Fig. 2: Soldering Jig designed for forming interconnects B. Encapsulation stage The microchip thermistor and the solder bonds have to be encapsulated with a polymer micro-pod to protect against mechanical, thermal and chemical stresses to which the electronic yarn would be subjected during fabric production, garment manufacturing and later during its use. The micro-pod would also protect the microchip during washing, spinning and drying. As such the creation of the micro- pod is an important step of FET. In order to enhance the mechanical strength of the interconnects, the copper wire with soldered microchips were twisted with two 167dTex/48 polyester yarns and then the microchip was encapsulated with a thermally conductive resin. Two types of encapsulation material were tested (Multi-Cure® 9-20801 and 9001-E-V-3.5, a) b) c) Electronic Temperature Sensing Yarn by Pasindu Lugoda, Tilak Dias, Rob Morris
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31. rebecca.stewart@qmul.ac.uk omaterials 2016, 6, 147 5 of 9 d electrode deposition confirms that every layer of the device was compactly assembled by the mple transfer and deposition procedures. Figure 5. Photograph (a) and optical microscopy image (b) of textile-based transistor device. Figure 6 shows the typical output (I D-V D, where I D is the drain current and V D is the drain voltage) d transfer (I D-V G, where V G is the drain voltage) characteristics of the textile-based transistors. e well-defined gate modulation in the output curves (Figure 6a) reveals the ohmic contact between composite film electrode and the transferred semiconductor/dielectric layers. The transistor device hibited a saturation current of 1.0 mA at V G = 3 V and V D = 1 V. To evaluate the electrical aracteristics of the transistors, such as the charge carrier mobility (µh), on/off current ratio (I on/I off), d threshold-voltage (V T), the drain current was measured while sweeping V G from 0 V to 4 V at a e of 33 mV·s 1 and a constant V D value of 1 V (Figure 6b). Despite the manual fabrication process ambient conditions, the transistors made of the composite film electrode showed a reasonably gh I on/I off of 4.5 ⇥ 104 and low V T values around 1.5 V. From the slope of the V G vs. |I D| rves obtained for more than five devices, the average field-effect mobility was calculated to be cm2·V 1·s 1, which is much higher than those reported in other P3HT-based transistors gated h conventional dielectrics (0.1–0.01 cm2·V 1·s 1) [13], but are comparable to other recent results on ctrolyte-gated polymer transistors [14]. It has been speculated that the high mobility value in this ult is due to the penetration of ions from the ion gel dielectric into the active channel that fills the rier traps and acts as a dopant in the P3HT film [15,16]. Flexible Textile-Based Organic Transistors Using Graphene/Ag Nanoparticle Electrode Youn Kim, Yeon Ju Kwon, Kang Eun Lee, Youngseok Oh, Moon-Kwang Um, Dong Gi Seong, and Jea Uk Lee
32. rebecca.stewart@qmul.ac.uk An investigation of integrated woven electronic textiles (e-textiles) via design led processes Priti Veja
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35. rebecca.stewart@qmul.ac.uk Thank you