engleski

Electrical percolation in onion like carbon composites

Electrically percolative polymer-based composites have been attracting much attention because of their potential applications such as electroactive materials, sensitive materials, and electromagnetic coatings. Owing to advanced electrical, thermal and mechanical properties, various carbon nanoparticles like carbon nanotubes or carbon black have been widely studied and often used as nanofillers in past few years. The main advantage of carbon nanotubes versus other carbon nanofillers is their extremely low percolation treshold. The onion-like carbons (OLCs), consisting of stable defected multishell fullerens, exhibit high conductivity similar to carbon nanotubes. It was also found that percolation threshold in OLC composites can be 10 vol%. In this presentation we have investigated how further reduce percolation threshold in onion like carbon composites. The search of electrical percolation was performed in composites with various polymer matrix like Polymethylmetacrylate (PMMA), Polyurethane (PU), Polydimethylsiloxane (PDMS) and epoxy resin. It was demonstrated tha after annealing of OLC/PMMA and PU composites above glass transition temperature however below melting point percolation threshold decreases. It was found also that percolation threshold is dependant from OLC aggregate size. Close to the percolation threshold the value of the complex dielectric permittivity is high in all investigated frequency rabge from hertz to terahertz. Therefore, investigated OLC composites are promising candidates for various electronic applications.

onion like carbon; nanocomposites; percolation

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