Conducting materials as building blocks for electronic textiles

Abstract

Abstract: To realize the full gamut of functions that are envisaged for electronic textiles (e-textiles) a range of semiconducting, conducting and electrochemically active materials are needed. This article will discuss how metals, conducting polymers, carbon nanotubes, and two-dimensional (2D) materials, including graphene and MXenes, can be used in concert to create e-textile materials, from fibers and yarns to patterned fabrics. Many of the most promising architectures utilize several classes of materials (e.g., elastic fibers composed of a conducting material and a stretchable polymer, or textile devices constructed with conducting polymers or 2D materials and metal electrodes). While an increasing number of materials and devices display a promising degree of wash and wear resistance, sustainability aspects of e-textiles will require greater attention.

Keywords: 2D materials; Fabric; Metal; Polymer; Sustainability.

Figure 1

Volume electrical conductivity as a function of Young’s modulus for electrically conducting fibers or yarns based on metals (yellow) such as aluminum (Al), gold (Au), silver (Ag) and copper (Cu), MXenes (purple), carbon nanotubes (light gray), graphene (orange), composites of a carbon allotrope and a polymer (dark gray), doped conjugated polymers (green) or blends of a conducting and insulating polymer (blue), as well as insulating fibers or yarns with a conducting polymer or carbon allotrope coating (pink) and Ag plated yarns (red); the Ashby plot was constructed based on data from References –.

Figure 2

Schematic of the textile manufacture process; an insulating polymer, a conducting material, or a composite or blend of those constitutes the raw material for fiber spinning. This is followed by yarn twisting (not shown), and the yarn in turn may be dyed with a functional ink, and/or converted into a fabric by weaving, knitting, or felting (not shown). Fabrics can be further functionalized by printing, embroidery, or dyeing/coating.

Figure 3

Conductive metallic textiles and textile-based electronic devices. (a) Scanning electron microscopy (SEM) image of the surface of a textile after the permeation of the specialized ink. Scale bar = 300 μm. (b) Cross-sectional SEM image of the fiber bundle after printing. Scale bar = 30 μm. (c) Photograph of the stencil-printed textile electrode. (d) SEM image of the surface of a textile after electroless deposition (ELD). (e) Cross-sectional SEM image of the fiber bundle after ELD. (f) Optical microscope image of the metal pattern on a textile. Scale bar = 400 μm. (g) Schematic of the structure of a patterned light-emitting textile. (h) Photograph of the light-emitting textiles conformal to a human arm. (i) Photograph of a light-emitting textile displaying the “smiling face” emoji. (j) Photograph of a light-emitting textile displaying the number 8; (a–c) Reprinted with permission from Reference . © 2017 Wiley. (d–f) Reprinted with permission from Reference . © 2018 Wiley. (g–j) Reprinted with permission from Reference . © 2020 Elsevier.

Figure 4

(a) Chemical formula of poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS). (b) SEM image of a freeze-fractured PEDOT:PSS dyed silk yarn with charging artifacts indicating penetration of the conductive coating, and (c) SEM image of freeze-fractured PEDOT:PSS dyed silk yarn (sputtered with palladium). Scale bars = 2 µm. (d) Photograph of PEDOT:PSS dyed silk yarn. (e) Electrically conducting Chalmers logo, connected to a blue light-emitting diode and a battery (not shown), machine embroidered using a PEDOT:PSS coated silk yarn. (f) Schematic of embroidery of conducting silk yarns (blue) and silver-plated polyamide thread (gray) through several layers of a wool fabric, and (g) embroidered textile thermoelectric generator. (h) PEDOT:PSS coated silk yarns stitched onto cotton swatches line drying after machine wash tests. (b–d, h) Reprinted with permission from Reference . © 2017 American Chemical Society. (e) Reprinted with permission from Reference . © 2018 Wiley. (f) Reprinted with permission from Reference . © 2020 Elsevier.

Figure 5

(a, b) Layered dip coating technique to produce a parallel-plate capacitor on polyester, using graphene nanoplatelets as the electrode material, and h-BN as the dielectric material. (c) Screen-printed impedimetric biosensor on cotton. (d) Electro-thermochromic butterfly patterns as a function of the applied voltage across the graphene-nanoplatelet fabric. (e) High-resolution graphene field-effect transistor in an inverted-staggered configuration, fabricated by inkjet printing on polyurethane-planarized cotton, with poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) acting as the gate material and h-BN as the dielectric. (f) SEM image of an all MXene Ti₃C₂T_X fiber. (g) SEM image of the cross-section of a MXene/polyurethane composite outer sheath surrounding the inner polyurethane core. (a, b) Reprinted with permission from Reference . © 2019 Royal Society of Chemistry. (c) Reprinted with permission from Reference . © 2018 Electrochemical Society. (d) Reprinted with permission from Reference . © 2020 Royal Society of Chemistry. (e) Reprinted with permission from Reference . © 2017 Springer Nature. (f) Reprinted with permission from Reference . © 2020 Springer Nature. (g) Reprinted with permission from Reference . © 2020 Wiley.