Multiscale Structure Evolution in Electrically Conductive Nanocomposites Studied by SAXS

The successful introduction of nanostructured materials is hampered by the lack of a quantitative and qualitative understanding of the structure-property relationship within the nanocomposites. Variation in the electrical conductivity of nanocomposite materials depends on the structure evolution of the nanoscale fillers within the polymer phase. This article pertains to the small angle x-ray scattering study of electrically conductive nanocomposites to understand the structure-property relationship. The nanocomposites in this study are comprised of thermoset polyurethane as the matrix material with carbon nanotubes as the filler material. A percolation threshold of 0.5% wt/wt was observed along with substantial changes in the electrical conductivity of the nanocomposites. The small angle x-ray scattering data exhibits mass and surface fractal regimes indicating multiple structure evolution in the nanocomposites. Moreover, the data is interpreted using the crossovers of the scaling laws and sizes are measured to characterize the microstructure with a possible explanation for structural development.