Several shielding applications, to protect human health and electronic devices against dangerous effects of electromagnetic radiation, require solutions that fabrics can suitably fulfil. Here, we will investigate the electromagnetic interference shielding effectiveness of polypyrrole-coated polyester textiles, in the frequency range 100-1000 MHz. Insertion losses for several conductive fabrics with different surface resistivity ranging from 40 Ω till the very low value of 3 Ω were evaluated with a dual-tem cell. Correlations between the shielding effectiveness and the conductivity of composites are also discussed.

Several shielding applications, to protect human health and electronic devices against dangerous effects of electromagnetic radiation, require solutions that fabrics can suitably fulfill. Here, we will discuss the electromagnetic interference shielding effectiveness of polypyrrole-coated polyester nonwoven textiles, in the frequency range 100—800 MHz. Insertion losses for samples with different surface resistivity ranging from 40 Ω/sq till the very low value of 3 Ω/sq were measured with a dual-transverse electromagnetic cell. We found a correlation between the shielding effectiveness and the surface conductivity of composites. For the sample with the lowest surface resistivity, we obtained an electromagnetic shielding effectiveness of 37 dB.

Electrically conductive nanocomposites from cellulose nanofibrils (CNF) were successfully produced by in situ polymerization of aniline onto CNF, and studied by open circuit potential (Voc), four probe direct current (dc) electrical conductivity, ultraviolet-visible (UV-Vis) spectroscopy and scanning electron microscopy (SEM). The oxidative polymerization of aniline using ammonium peroxydisulfate in hydrochloric acid aqueous solutions was realized by the addition of nanofibrils leading to an aqueous suspension of CNF coated with polyaniline (PANI). This procedure lead to stable, green suspensions of CNF coated with PANI in the emeraldine oxidation state as demonstrated by Voc and UV-Vis analyses. Electrically conductive films of this cellulose nanocomposite could be cast from aqueous solutions with conductivity close to the conducting polymer, yet with the potential for more useful flexible films.

ABSTRACT

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