Thin film nanocomposites based on SBM triblock copolymer and silver nanoparticles: morphological and dielectric analysis

Abstract

Hybrid organic/inorganic thin film nanocomposites based on poly(styrene)-b-poly(butadiene)-b-poly(methyl methacrylate) (SBM) triblock copolymer and silver nanoparticles (Ag) have been prepared and characterized. In order to improve the compatibility of nanoparticles with the polymeric matrix, their surface has been modified with dodecanethiol surfactant, which enabled a good dispersion of nanoparticles through the triblock copolymer, without the formation of aggregates. By atomic force microscopy (AFM), the dispersion level of nanoparticles has been analyzed, together with their effect on the thin film morphology, for nanocomposites up to 15 wt% of nanoparticles. Dielectric properties of nanocomposites have been studied by dielectric relaxation spectroscopy (DRS), analyzing the effect of nanoparticles on dielectric properties. Even if conductivity and permittivity of composites increased with nanoparticle content, percolation threshold was found to be at around 15 % in volume. Morphologically analyzed nanocomposites were, in this way, below the threshold.