Sheet Resistance of Continuous Filament Nonwoven Fabrics

Two modeling techniques are introduced to predict the sheet resistance of electrically conductive continuous filament nonwoven fabric: a two-dimensional (2-D) discrete filament stochastic resistor network simulation, and a simple analysis using a laminate analogy. The effects of anisotropy and sample size are considered. Results are compared with experiments on a silver coated point bonded nylon nonwoven fabric. For this particular sample, experimental sheet resistance results are significantly under-predicted by the 2-D analytical and simulation approaches where perfect inter-filament bonding is assumed. The utility of the 2-D perfect bonding predictions as a ultimate lower bound on the sheet resistance that may be achieved by extremely well-bonded continuous filament networks is discussed. Simulations of 2-D filament webs with poor inter-filament bonding and moderate anisotropy are shown to agree well with the present experiments. Taken together, the present results suggest that modeling of the in-plane conduction behavior of a general continuous filament nonwoven fabric requires a 3-D structural approach to capture the effect of an appropriate number density of inter-filaments bonds.