Evaluation and development of electrical conductivity models for nickel nanostrand polymer composites

Abstract

The electrical conductivity of composites and polymeric‐based systems is frequently improved by the addition of conductive additives to form a conductor–insulator binary system. This study considers nickel nanostrands as a conductive element in polymer systems. Materials characteristics are considered in order to form a basis for understanding and predicting the electrical percolation behaviors of nanostrand composites, specifically seeking models that can distinguish between different polymer systems. Empirical percolation data for nickel nanostrands in four different polymeric systems is presented and used to evaluate candidate electrical conductivity models. Classical percolation approaches are found to not show good fit, but more advanced models are able to provide good correlation to tested results. Specifically, Tunneling Percolation (TPM) models and the Two Exponent Phenomenological Percolation Equation (TEPPE) model based on the Generalized Effective Media (GEM) theory show good fit. A combined TEPPE‐TPM approach is developed that applies tunneling percolation to the GEM theory. This combined model includes tunneling considerations in equations that accurately represent behaviors in all regions of percolation behavior. POLYM. ENG. SCI., 55:549–557, 2015. © 2014 Society of Plastics Engineers

Recent advances in carbon-based polymer nanocomposites for electromagnetic interference shielding

“…Although the percolation threshold and percolation approaches have been vastly considered to model the electrical conductance behaviour of polymer nanocomposites containing conductive nanoparticles, classical percolation approaches have been found by many researchers to display a poor fit to most experimental results [250][251][252]. Other approaches, as tunnel-like conduction based models, such as Tunnelling Percolation (TPM), and the Two Exponent Phenomenological Percolation Equation (TEPPE) based on the Generalized Effective Media (GEM) theory or even combined models, have been considered [253].…”

“…Nevertheless, as percolation threshold has to be taken into account, tunnelling-percolation models (TPM) have been considered, such as the one proposed by Rubin et al [255]. In Hansen et al [253], authors used a simplified Hertz distribution for particle distribution assuming a distance between conductors inversely proportional to the volume fraction of nanoparticles () and directly proportional to the percolation threshold ( c ):…”

“…Hansen et al [253] demonstrated by modelling the electrical conductivity of several types of polymer-based systems reinforced with conductive nanostrands that the classical electrical percolation model as shown in Eq. 1 cannot distinguish between differences in the percolation limit across polymers, not lying within the proper region Wang et al [266] have considered the modeling of the electrical conductivity of CNTreinforced polymer nanocomposites by considering three main elements: the percolation threshold, approached by means of selecting an effective medium theory; possible interface effects, modeled by introducing an interfacial conductivity assuming a "thinlycoated" CNT; and tunneling-assisted interfacial conductivity, in order to take into account the possible influence of electron tunneling on interface conductivity.…”

Characterization of nickel nanostrand nanocomposites through dielectric spectroscopy and nanoindentation

“…). This unique structure promotes electrical conductivity at very small volume fractions of Ni‐Ns and improved conductivity compared to many other filled nanocomposites [] (see Table for percolation thresholds and percolation limits based on several of the polymers studied in this article; the percolation indicates when the matrix is saturated with filler, and conductivity does not significantly increase beyond this volume percentage). Similar to various other nanocomposites with conductive fillers [], Ni‐Ns‐based nanocomposites show a substantial change in resistance when placed under strain .…”

Accurate Prediction of Knee Angles during Open-Chain Rehabilitation Exercises Using a Wearable Array of Nanocomposite Stretch Sensors

“…This work utilizes a triphasic silicone/nickel composite [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ] with two different nickel filler materials—nickel nanostrands (NiNs, (18.76 wt%); Figure 1 a) and nickel-coated carbon fiber (NCCF, (3.13 wt%), Figure 1 b). The resulting sensors are inversely piezoresistive (negative correlation between strain and electrical resistance).…”