Multiscale Model for the Extreme Piezoresistivity in Silicone/Nickel Nanostrand Nanocomposites

Abstract

Extreme piezoresistivity was discovered in a silicone/nickel nanostrand (silicone/NiNs) nanocomposite. A novel technique was developed to study the charge transport phenomena responsible for the piezoresistive mechanism in the silicone/NiNs system using conductive nanoindentation. A quantum mechanical tunneling (QMT)/percolation model was developed, which bridges the gap between quantum effects at the nanoscopic scale and bulk material response at the macroscopic scale. The predictions of this model are compared to experimental measurements.

Piezoresistive in-situ strain sensing of composite laminate structures

“…The issue of routing circuitry to the point of interest must also be considered for this approach. Carbon nanotubes [14,15], carbon black [16], and nickel nanostrands [17]. This paper will focus on nickel nanostrand composites due to their extremely large piezoresistive effect.…”

“…where h is the Planck constant (J s), e is the electron charge (C), m is the electron mass (kg), k is the tunneling barrier height (J), and s is the distance between particles (m) [17]. Thus the resistivity of a nanojunction is a function of the inter-particle distance, s. As a nanocomposite is strained s will change and a piezoresistive signal is obtained.…”

Evolution of nano-junctions in piezoresistive nanostrand composites

“…Attempts have been made by Johnson et al to develop a numerical model that can both explain and predict the behavior of this material under strain [23,24]. Johnson's model predicts that quantum mechanical effects play a principal part in the change of resistivity in the composite material, as opposed to other proposed theories such as density or alignment changes of conductive filler [25].…”

“…networks [24,27]. While the resultant approach shows promising agreement with general resistance trends, many parameters in the simulation were approximated using incomplete assumptions, and current models of gap evolution are extremely simplistic [28,29].…”

“…The quantum tunneling barrier height of a material (the resistance that a material naturally has to certain quantum effects) is critical for the accuracy of these calculations. Previous work pioneered a new method to properly measure this barrier height involving precision nanoindentation with a conductive probe [24,27]. This paper utilizes recent refinements of the technique as outlined by Koecher et al [30] to provide improved and robust barrier height results on the material.…”