Evaluation and Development of Electrical Conductivity Models for Nickel Nanostrand Polymer Composites

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. (c) 2014 Society of Plastics Engineers