Fluid/Fiber Interactions and the Conductivity of Inkjet Printed Ag on Textile Substrates

Abstract

X-ray tomographic reconstruction reveals that the distribution of Ag after inkjet printing and sintering a nanoparticle conducting ink on a woven polyester textile substrate is strongly controlled by the fiber surface properties and fabric architecture. Capillarity confines the transport of the ink predominantly within the warp or weft yarns of the fabric and there is little transport of ink between the yarns. Changing the fiber surface energy through the Scotchgard treatment leads to an increase in the contact angle, reducing ink transport along the fibers and an increase in conductance. A similar effect is seen when printed drop spacing is reduced, increasing the local Ag concentration. Electrical conductivity is strongly influenced by the fiber density in each yarn direction and, in this case, the different densities lead to different electrical conductance values. Through the use of image segmentation, it is possible to identify a low level of electrical interconnection between the warp and weft yarns. Conductance within a yarn is shown to depend on Ag concentration via a percolation mechanism and this is confirmed by a simple model relating the volume of the largest interconnected Ag object present to the measured conductance. These results illustrate the complexity of the interaction between conductive inks and fibrous substrates and that concepts, such as sheet resistance, used to characterize printed conductors on solid substrates are not applicable to textile substrates.

Metallisation of Textiles and Protection of Conductive Layers: An Overview of Application Techniques

“…The best conductivity was observed on polyester/cotton 85%/15% fabric, up to 1.85 × 10 6 S/m for six layers. Wang et al [51] investigated the fluid-fibre interactions and corresponding conductivity of inkjet-printed Ag on a woven polyester Ref. [37] Copyright 2021, American Chemical Society); (b) presentation of a drop of Ag ink distribution on fibers with different diameters (reprinted with permission from Ref.…”

“…Since textiles usually act as natural insulators, it is necessary for them to become conductive prior to electrodeposition. This is feasible by the creation of conductive layers (in a pre-treatment step) on a textile surface, using different metals, such as Ag [51,87], Cu, [88][89][90], Ni [91], Mxenes [92], Ni-Co selenide nanowires [93], NiMoO 4 /CoMoO 4 nanorods [94], LaMnO 3 /MnO nanoarrays, ZnO nanostructures deposited on an Ni-Cu-Ni conductive layer [95], and LiMn 2 O 4 [96], conductive polymers [97] or carbon-based materials [11,[22][23][24][25][26]. Schematic presentation of a typical electrochemical deposition process of a metallic layer onto PES fabric, using a three-electrode system, is shown in Figure 5a, where the deposition of Ni 3 Se 2 NPs is carried out on the conductive fabric (used as a working electrode), resulting in a metallic polyester layered fabric.…”

“…The best conductivity was observed on polyester/cotton 85%/15% fabric, up to 1.85 × 10 6 S/m for six layers. Wang et al [ 51 ] investigated the fluid-fibre interactions and corresponding conductivity of inkjet-printed Ag on a woven polyester (PES) substrate. The study, using X-ray tomographic reconstruction, showed that the distribution of inkjet-printed and sintered nanoparticulate conductive Ag ink depends strongly on the properties and architecture of the fibre surface ( Figure 3 d).…”

“…[ 50 ] Copyright 2021, American Chemical Society); ( d ) XCT 3D reconstruction images of Ag (blue-green) deposited on polyester fabric (grey) with an increasing number of layers (reprinted with permission from Ref. [ 51 ] Copyright 2021 American Chemical Society); ( e ) textile heating actuators—computer designed patterns and thermal images of Ag inkjet printing PP spun non-woven textile (reprinted with permission from Ref. [ 52 ] Copyright 2021, Elsevier); and ( f ) digital moisture sensor signals recorded from the inkjet printing part on the fabric (reprinted with permission from Ref.…”

“…Copyright 2021, American Chemical Society); (c) SEM images of Ag inkjet printing, together with a combination of cellulose nanofibrils/glycerol on woven cotton fabric (reprinted with permission from Ref [50]. Copyright 2021, American Chemical Society); (d) XCT 3D reconstruction images of Ag (blue-green) deposited on polyester fabric (grey) with an increasing number of layers (reprinted with permission from Ref [51]. Copyright 2021 American Chemical Society); (e) textile heating actuators-computer designed patterns and thermal images of Ag inkjet printing PP spun non-woven textile (reprinted with permission from Ref [52].…”