High Electromagnetic Interference Shielding Effectiveness of Carbon Nanotube–Cellulose Composite Films with Layered Structures

Abstract

Abstract Flexible and electrically conductive carbon nanotube (CNT)–cellulose composite films are fabricated by a green route based on sodium hydroxide/urea aqueous solution. Both single‐walled carbon nanotubes (SWCNTs) and multi‐walled carbon nanotubes (MWCNTs) are investigated as conductive fillers. The microstructure and physical properties of the films are characterized extensively. It is observed that CNTs form layered conductive networks in the cellulose matrices during the drying process. The electromagnetic interference (EMI) shielding effectiveness (SE) of these composite films is also investigated. The results exhibit that the EMI SE of the materials is in accordance with electrical conductivity, which is highly dependent on the CNT loadings. Compared to MWCNT–cellulose composite films, the films with SWCNT show more effectiveness as EMI materials in the frequency range of 12–18 GHz. With SWCNT loading of 10 wt%, the EMI SE can reach 32.5–40 dB. Considering the thickness and density of the material, furthermore, the SWCNT–cellulose film possesses an extremely high specific EMI SE value of about 7678 dB cm 2 g −1 , which is due to the unique layered structures of CNTs. Thus, these flexible conductive composite films have the potential to be used as high‐efficiency shielding materials against electromagnetic radiation in advanced application fields.