Lightweight Hierarchical Carbon Nanocomposites with Highly Efficient and Tunable Electromagnetic Interference Shielding Properties

High-performance electromagnetic interference shielding is becoming vital for the next generation of telecommunication and sensor devices among which portable and wearable applications require highly flexible and lightweight materials having efficient absorption-dominant shielding. Herein, we report on lightweight carbon foam–carbon nanotube/carbon nanofiber nanocomposites that are synthesized in a two-step robust process including a simple carbonization of open-pore structure melamine foams and subsequent growth of carbon nanotubes/nanofibers by chemical vapor deposition. The microstructure of the nanocomposites resembles a 3-dimensional hierarchical network of carbonaceous skeleton surrounded with a tangled web of bamboo-shaped carbon nanotubes and layered graphitic carbon nanofibers. The microstructure of the porous composite enables absorption-dominant (absorbance ∼0.9) electromagnetic interference shielding with an effectiveness of ∼20—30 dB and with an equivalent mass density normalized shielding effectiveness of ∼800—1700 dB cm3 g–1 at the K-band frequency (18—26.5 GHz). Moreover, the hydrophobic nature of the materials grants water-repellency and stability in humid conditions important for reliable operation in outdoor use, whereas the mechanical flexibility and durability with excellent piezoresistive behavior enable strain-responsive tuning of electrical conductivity and electromagnetic interference shielding, adding on further functionalities. The demonstrated nanocomposites are versatile and will contribute to the development of reliable devices not only in telecommunication but also in wearable electronics, aerospace engineering, and robotics among others.

Authors:
Pitkänen Olli, Tolvanen Jarkko, Szenti Imre, Kukovecz Ákos, Hannu Jari, Jantunen Heli, Kordas Krisztian

Publication type:
A1 Journal article – refereed

Place of publication:

Keywords:
carbon foam, carbon nanotubes, flexible, Lightweight, melamine foam, nanocomposite, piezoresistive

Published:
6 May 2019

Full citation:
Olli Pitkänen, Jarkko Tolvanen, Imre Szenti, Ákos Kukovecz, Jari Hannu, Heli Jantunen, and Krisztian Kordas ACS Applied Materials & Interfaces 2019 11 (21), 19331-19338 DOI: 10.1021/acsami.9b02309

DOI:
https://doi.org/10.1021/acsami.9b02309

Read the publication here:
http://urn.fi/urn:nbn:fi-fe202002276624