Percolative Composites with Carbon Nanohorns: Low-Frequency and Ultra-High Frequency Response.

Olga V Sedelnikova,Lyubov G Bulusheva,Pavel E Plyusnin,Alexander V Okotrub,Kseniya I Baskakova,Artem V Gusel’Nikov

doi:10.3390/ma12111848

Abstract

We systematically studied the electromagnetic properties of carbon nanohorns (CNHs) and polystyrene composites filled with CNHs in static regime, low frequency and microwave regions. CNHs were synthesized using the direct current arc-discharge method using solid graphite rods and graphite rods filled by melamine mixed with graphite powder. Transmission electron microscopy and thermo-gravimetric analysis showed that CNH agglomerates are the main product, while the addition of melamine promotes the formation of graphite balls. Graphitic contamination causes the internal leakage of inter-agglomerate capacity, lowering the permittivity and enhancing the conductivity of composites. The permittivity of CNH/polystyrene composites increases with the filler fraction, and near the dielectric threshold electromagnetic characteristics of the composites exhibit critical behaviour. Our results suggest that CNHs with relatively high values of permittivity and contact resistance could be used as high-k materials.

Highlights

Today, polymer composites with conductive particles are an actively explored field
We have found just a few works devoted to three-component polymer composites, where the second filler was presented by graphene [18,19], ferromagnetic particles [20] or their hybrids [21,22] in addition to the carbon nanohorns (CNHs)
We systematically investigate the electromagnetic properties of CNHs synthesized using the arc discharge method

Summary

Introduction

The near-percolated composites with carbon nanostructures are promising for fabrication of high-k materials [1,2]. Comparison of the dielectric properties of thin polymer films with different types of carbon nanostructures (carbon nanotubes and nanofibers, graphene nanoplatelets) showed the higher permittivity and conductivity when using wire-shaped structures [6]. The spherical inclusions, such as carbon black [7] and onion-like carbon [8], showed the less impressive responses due to lower conductivity and less effective composite filling

Objectives

Methods

Results