Low filled conductive P(VDF-TrFE) composites: Influence of silver particles aspect ratio on percolation threshold from spheres to nanowires

Abstract

Polymer composites filled with silver nanowires enable the highest value of electrical conductivity known up to now in the case of conductive nanoparticle dispersion with a percolation threshold less than 1vol%. Silver nanowires with high aspect ratio were elaborated by two types of synthesis: electrochemical deposition in a template and polyol synthesis. For the first time the influence of each kind of nanowires in composites was studied and compared to spherical nanoparticles as reference. The value of percolation threshold and conductivity level above the percolation threshold were measured and compared. These silver nanowires were introduced into poly(vinylidenedifluoride-trifluoroethylene) in comparison to spherical silver nanoparticles. The preparation method modified the effective aspect ratio of nanowires. The low percolation threshold and the microscopy observations confirmed the good dispersion of nanowires in composites. The lowest percolation threshold was determined in the case of the polyol synthesis nanowires (0.63vol%) in comparison with electrochemical deposited nanowires (2.2vol%). The level of conductivity above the percolation threshold obtained with each kind of particles is in the same range near 100S.m−1. The value of electrical conductivity obtained above the percolation threshold is unusual at this low content of conductive filler and is observed for the first time in a conductive polymer composite.