The Effect of Fiber Architecture on the Conductance of Inkjet Printed Ag on Electronic Textile Substrates

A nanoparticle Ag ink has been inkjet printed on six different plain-weave polyester textile substrates without any further surface treatment. They are manufactured from the same composition polyester fibers but with different fiber diameters and yarn structures. These different fabric architectures are shown to strongly influence the electrical conductance of the Ag deposit after drying and sintering. X-Ray computed tomography (XCT) shows the Ag to have penetrated the fiber yarn tows to form several interconnected conducting networks that are electrically isolated. Conductance scales linearly with the largest Ag network volume in the XCT reconstruction, consistent with a percolation network model for conductance. Three key features of textile architecture are shown to influence electrical performance after printing. The free volume between the fibers within the individual yarn tows should be similar to the volume of ink delivered, excess ink leads to poor pattern resolution and too little ink reduces the size of the Ag objects. The mean pore radius in the tows must be sufficient to allow capillary transport of the ink where crossing yarns impede the ink drop trajectory. Fabrics with a low specific fiber surface area contain larger Ag objects and show a larger conductance.