3D-structured carbon nanotube fibers as ultra-robust fabrics for adaptive electromagnetic shielding

Wireless communication technology is indispensable in our daily lives, but it also results in serious electromagnetic radiation pollution. Hence, developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave (EMW) responses holds significant promise for future electromagnetic shielding devices. In this study, we propose an electromagnetic shielding switch (ESS) characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional (3D) carbon nanotube-based spacer fabric (CNT-SF) and modifying CNT-SF with chemical vapor deposition (CCNT-SF). The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density, measuring 128 S/m transversely and 447 S/m vertically. This characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation, resulting in anisotropic electromagnetic shielding performance (33 dB transversely and 87 dB vertically). This feature enables switchable shielding with an on/off ratio of 2.64. Furthermore, the unique 3D structure confers excellent mechanical properties on the fabric, with compressive strength reaching 120 kPa. As a flexible, lightweight, and mechanically robust ESS, the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments.