Influence of textile structure on the wearability of printed e-textiles

To achieve durable printed circuits on textiles, it is necessary to print low-cost polymer films that interface the fabric with the printed circuit. The film smooths the surface of the fabric to enable the printing of thin and flexible conductive films on the fabric. When printed, the thickness of the polymer films can dominate the fabric and limit the flexibility of the printed e-textile. This paper investigates the reduction of the polymer film thickness for printed and wearable e-textiles by controlling the thread count of the fabric using different blends of polyester/silk/cotton fabrics. A $50 \mu \mathrm{m}$ thick polyurethane interface layer with a surface roughness, Ra value of $1.7 \mu \mathrm{m}$ is reported on a 100% plain weave polyester fabric. The PU thickness is 4 times less than the state of the art and shows more than 80 % reduction in the proportion of interface material to fabric thickness of the printed e-textile. This minimizes the impact of the printed film on the fabric.