Piezoresistance of flexible tunneling-percolation networks

We model changes in the conductivity of flexible composite films stressed by bending. By treating stress as a perturbation of the effective medium conductivity, we obtain an expression of the piezoresistance as a function of four material parameters. The model correctly predicts resistance spikes and their recovery under the action of viscoelastic forces, in good agreement with experimental observations over stress cycles. The theory may be used to design composite materials for high-sensitivity touch sensors.