Asymmetric c-MWCNT/AgNWs/PANFs hybrid film constructed by tailoring conductive-blocks strategy for efficient EMI shielding

Currently, extensive utilization of wireless devices require human being tantamount to tackle electromagnetic wave pollution to avoid serious harm to health body and precision equipment. Herein, asymmetric structure hybrid film were developed from para-aramid nanofiber (PANFs), carboxylated multiwalled carbon nanotubes (c-MWCNT) and silver nanowire (AgNWs) through vacuum-assistant filtration and freeze drying route. The robust and high aspect ratio PANFs established matrix foundation for forming large scale hybrid film, which rendered feasible support for conductive building blocks c-MWCNT and AgNW. Thanks to the unique asymmetric porous structure, the as-prepared c-MWCNT/AgNWs/PANFs hybrid film with 8 wt% of c-MWCNT and 4 wt% of AgNW remained efficient EMI shielding performance, whose shielding effectiveness (SE) and specific effectiveness (SEE/t) reached 40.59 dB and 10678.17 dB cm2 g−1 at thickness of 0.061 mm in X band, respectively. Furthermore, the shielding effectiveness and absorption coefficient could be regulated by c-MWCNT content, AgNW content, and ratio of c-MWCNT and AgNW. With improving the conductive ratio, the c-MWCNT/AgNWs/PANFs hybrid film possessed tunable shielding effectiveness between 9.40~40.59 dB and absorption coefficient between 0.028~0.303. This work provided feasible avenue for controlling electromagnetic feature through tailoring conductive blocks strategy.