Giant piezoresistivity in aligned carbon nanotube nanocomposite: account for nanotube structural distortion at crossed tunnel junctions

Abstract

High piezoresistivity is critical for multifunctional carbon nanotube polymer composites with sensing capability. By developing a new percolation network model, this work reveals theoretically that a giant piezoresistivity in the composites can be potentially achieved by controlled nanotube alignment resulting from field based alignment techniques. The tube-tube and/or tube-matrix interaction in conjunction with the aligned carbon nanotube networks are fully considered in the newly proposed model. The structural distortion of nanotubes is determined self-consistently by minimizing the pseudo-potential energy at crossed-tube junctions based on the Lennard-Jones potential and simulation of coarse grain molecular dynamics. The tunneling transport through crossed-tube junctions is calculated by the Landauer-Büttiker formula with empirical fitting by first-principle calculation. The simulation results also reveal that the piezoresistivity can be further improved by using low carbon nanotube loadings near the percolation threshold, carbon nanotubes with a small aspect ratio, high intrinsic conductivity and polymers with a small Poisson's ratio. This giant piezoresistive effect offers a tremendously promising future, which needs further thorough exploration.

Mechanical and Strain-Sensing Capabilities of Carbon Nanotube Reinforced Composites by Digital Light Processing 3D Printing Technology

“…In this context, CNT doped nanocomposites have a great potential and applicability. This is explained by the intrinsic piezoresistivity of CNTs [13,14], the contact conductive mechanism between CNTs and the tunneling effect that takes place between adjacent nanotubes. The combination of these factors leads to an enhanced strain sensitivity, much higher than those achieved for conventional metallic gauges [15][16][17][18][19].There are several studies of materials manufactured by 3D printing with CNTs as conductive fillers.…”

Piezoresistive Strain Sensors Based on Carbon Nanotube Networks: Contemporary approaches related to electrical conductivity

“…Finally, Gong and Zhu revealed that a giant piezoresistivity may be achieved by controlling the cnt alignment in cnt/ polymer nanocomposites [73]. Figure 14(a) and (b) shows that the highest piezoresistive effect may be achieved in both directions parallel and perpendicular to the alignment by controlling the maximum cnt alignment angle between 10° and 20°.…”

“…Until now, only a limited number of studies [44], [56], [61]- [73] have explored the piezoresistive behavior and the associated mechanisms of cnt/polymer composites quantitatively. Analytical studies [63], [64], [68], usually based on the Simmons tunneling effect at the cnt junctions [24], have tried to explain the mechanism of piezoresistivity in cnt/polymer nanocomposites.…”

“…The directional effect of CNT alignment on the resistance change ratio: (a) parallel and (b) perpendicular to the alignment of the CNTs[73].…”

Magneto-piezoresistivity in iron particle-filled silicone: An alternative outlook for reading magnetic field intensity and direction

“…In particular, several investigations have highlighted the existence of a giant piezoresistive effect (the electron conductivity can change by 9 orders of magnitude) in composite materials constituted by a silicone matrix filled by conductive microparticles at a volume fraction around percolation threshold [8][9][10].…”