Onion-like-carbon-based composite films: Theoretical modeling of electromagnetic response

A semi-empirical microscopic calculation of the dielectric permittivity of a thin film containing onion like carbons (OLC) has been performed. The theoretical data are found to be in quantitative agreement with Maxwell-Garnett theory and they agree qualitatively with results of a recent experimental dielectric analysis of OLC-based PMMA composites, also reported in this paper. For future applications of effective-medium theories, a simplified model of OLC cluster chains, viewed as conductive corrugated cylinders, has been developed. A perfect agreement between the polarizabilities obtained by the continuous-medium model and by full atomistic calculations is reported. This observation opens the possibility to use simplified electrostatic models to mimic complex OLC aggregates, especially in a polymer composite.