Analytical modeling of synergistic carbon nanotube/carbon black effects on the sensitivity of nanocomposite strain sensors

An analytical model is developed to predict the piezoresistive sensitivity of nanocomposite strain sensors considering physical properties of carbon nanotubes (CNTs) and carbon blacks (CBs) such as the orientation state, aspect ratio, waviness factor, and agglomeration. A Monte Carlo simulation approach is used to disperse hybrid CNTs/CBs into the matrix. The percolation model is used to introduce the percolation phenomenon into the nanocomposites. Afterward, the piezoresistive property of hybrid nanocomposites is determined using updated fillers’ positions after a stretch in a specific direction of nanocomposites. The nanocomposite resistivity is explored as a function of nanofiller volume fraction. The verification is accomplished by comparing model results with experiments. CNTs with higher aspect ratios and lower waviness factors have a beneficial effect on the electrical properties of hybrid nanocomposites. A good combination of conductive fillers leads to a better piezoresistive response, while a further increase in CB volume fraction cannot be beneficial.