Theoretical modeling for piezoresistive behavior of aligned carbon nanotube/polymer nanocomposites accounting for evolution of agglomerates morphology

Abstract

In this study, the electromechanical response of carbon nanotube (CNT)-reinforced polymer nanocomposites subjected to uniaxial deformation was investigated theoretically. For this purpose, a comprehensive analytical model that incorporated critical factors affecting the piezoresistive properties of CNT/polymer nanocomposites was proposed. To determine the effects of field-induced CNT alignment and the corresponding prolonged agglomeration morphology, an effective resistor network was established to predict piezoresistivity defined as the normalized resistance change of CNT/polymer nanocomposites. The proposed model accurately described the piezoresistive properties of randomly aligned CNT-based composites compared with a previously developed model, and its further validation was performed using experimental data obtained from the literature for CNTs aligned in a polymer matrix. A similar approach was used for the determination of a percolation threshold, which strongly correlated with piezoresistivity. In addition, the effect of each individual critical factor was examined to establish a desirable set of parameters that would either decrease the percolation threshold or increase the piezoresistivity of composites.