Detailed Morphology and Electron Transport in Reduced Graphene Oxide Filled Polymer Composites with a Segregated Structure

Polymer composites of a segregated network structure are dielectric polymer granules coated with electrically conductive nanoparticles at a low content, the quantity of the junctions between the granules determines the composites' mechanical properties, and the percolation network formed by the nanoparticles determines the electrical conductivity. Here, the morphology and electron-transport properties in reduced graphene oxide (rGO)-filled composites with a segregated structure based on polyvinyl chloride (PVC), poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)), and ultrahigh-molecular-weight polyethylene (UHMWPE) are studied. Optical and electron microscopies study of the microtome-formed cross sections have shown the morphology to be dependent on the polymer-the thinnest rGO layers are in UHMWPE-based composites, the thicker rGO layers are in PVC- and P(VDF-TFE)-based ones. The electrical conduction of the composites and the rGO-paper occurs through the same hopping conduction mechanisms within the wide temperature range, which allows to use the composites in applications where pure rGO is considered. Owing to thicker rGO layers open to the environment, PVC- and P(VDF-TFE)-based composites are more attractive, rather than the UHMWPE ones, in applications where layered materials are needed, for example, in lithium-ion batteries or supercapacitors. The UHMWPE-based composites look more promising as electrically conductive materials when mechanical strength is important. Morphology and electron-transport properties of reduced graphene oxide-filled polymer composites with a segregated structure based on polyvinyl chloride, poly(vinylidene fluoride-co-tetrafluoroethylene), and ultrahigh-molecular-weight polyethylene are studied-with decreasing temperature, the conduction occurs through nearest neighbor hopping, and then through 2D Mott variable-range hopping (2D Mott VRH) crossing over to Efros-Shklovskii VRH.image (c) 2024 WILEY-VCH GmbH