A finite element percolation tunneling approach on the electrical properties of carbon nanotube elastomer nanocomposite pressure sensors

A flexible pressure sensor utilizing carbon nanotubes (CNTs) is investigated employing a finite element methodology to delve into its electro-mechanical behavior. The responsive nature of the three-dimensional representative volume element, containing impenetrable CNT cylinders within an insulating hyperelastic elastomeric cube, is simulated to capture its sensitivity to pressure. Considering applied pressure and updated percolation pathways, a multi-step approach is employed to assess piezoresistivity. Upon adjusting positions of CNTs within the deformed state using the finite element method, novel pathways are identified using the critical distance criterion for percolation paths that contribute to the resistance network. Simulation results demonstrate good agreement with experimental data for resistivity and piezoresistive sensitivity of different CNT elastomeric nanocomposites. The finite element method helps to analyze influences of nanotube volume fraction, geometrical properties, and orientational configurations on the critical distance percolation onset. Lower CNT contents yield more substantial relative resistance changes due to fewer percolating routes.