A model is presented for the flow of inkjet-printed fluids into textiles based on capillary flow between fibers and diffusion of solvent into the fibers. Dispersions of PEDOT (Poly 3, 4 ∓ ethylenedioxythiophene), a conducting polymer, can be inkjet-printed onto fabric to form piezoresistive sensors. A problem is to get proper penetration of PEDOT into the fabric so that it does not easily flake off the surface. This penetration depends on a balance between wetting, evaporation and viscous flow of printed PEDOT suspensions between the fibers of the textile substrate.
This study addresses how these liquids flow within a yarn after being printed onto the fabric. Loss of liquid into the fiber limits spreading of the ink as the residual solids level builds up. Ink predominantly follows the path of a yarn but is treated as crossing between yarns at narrow crossing points. This model yields predictions for the distribution of conducting ink when printed onto fabric.
