Terahertz Shielding Properties of Carbon Black Based Polymer Nanocomposites.

Klaudia Zeranska-Chudek,Agnieszka Siemion,Mariusz Zdrojek,Ahmed Mdarhri,Christian Brosseau,Norbert Palka,Ilham Elaboudi

doi:10.3390/ma14040835

Abstract

The majority of industry using high-speed communication systems is shifting towards higher frequencies, namely the terahertz range, to meet demands of more effective data transfer. Due to the rising number of devices working in terahertz range, effective shielding of electromagnetic interference (EMI) is required, and thus the need for novel shielding materials to reduce the electromagnetic pollution. Here, we show a study on optical and electrical properties of a series of ethylene co-butyl acrylate/carbon black (EBA/CB) composites with various CB loading. We investigate the transmittance, reflectance, shielding efficiency, absorption coefficient, refractive index and complex dielectric permittivity of the fabricated composites. Finally, we report a material that exhibits superior shielding efficiency (SE)—80 dB at 0.9 THz (14.44 vol% CB loading, 1 mm thick)—which is one of the highest SE values among non-metallic composite materials reported in the literature thus far. Importantly, 99% of the incoming radiation is absorbed by the material, significantly increasing its applicability. The absorption coefficient (α) reaches ~100 cm−1 for the samples with highest CB loading. The EBA/CB composites can be used as lightweight and flexible shielding packaging materials for electronics, as passive terahertz absorbers or as radiation shields for stealth applications.

Highlights

For the last several years, the terahertz industry has experienced rapid growth, mainly due to new advancements in the main fields of terahertz technology, namely the terahertz sources, detectors and absorbers [1,2,3,4,5,6]
We report a series of highly shielding ethylene co-butyl acrylate/carbon black (EBA/CB) composites—shielding efficiency (SE) over 20 dB throughout 64–98% of the measured range, with main shielding mechanism defined as absorption
The studied samples exhibit total SE of 20 dB or higher for at least 64% of the studied range, which means the ethylene co-butyl acrylate (EBA)/CB composites shield over 99% of the incident radiation in more than half of the studied frequency range

Summary

Introduction

For the last several years, the terahertz industry has experienced rapid growth, mainly due to new advancements in the main fields of terahertz technology, namely the terahertz sources, detectors and absorbers [1,2,3,4,5,6]. Metals and composites based on metallic nanoparticles are still the most commonly used materials for EMI shields, there is a strong alternative—polymer composites with carbon nanofillers. Polymer composites based on carbon nanomaterials combine the mechanical durability and flexibility of the polymer matrix and optical and electrical properties of highly absorptive and electrically conductive carbon fillers. The addition of carbon fillers, e.g., graphene, carbon nanotubes or carbon black, can greatly influence the shielding properties of normally transparent polymer matrixes. The specific optical and electrical properties can be tuned by the inner structure of the composite and carbon filler loading. Polymer composites are resistant to corrosion and can be fabricated via modern industrial methods, like molding or extrusion

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Results

Conclusion