Ionic liquid-dispersed PDMS/SWCNT/Ag@Ni hybrid composite for temperature- and pressure-sensitive smart electromagnetic shielding applications

Abstract

The development of highly sophisticated self-adapting intelligent electronic and communication systems for applications in military, aerospace, robotics, etc. has prompted the requirement of externally stimulated green shielding materials to protect them from electromagnetic interference (EMI). However, it remains a big challenge to develop environmentally sensitive EMI shielding materials with an extremely high green shielding performance. Herein, an ionic fluid (IL)-impregnated polydimethylsiloxane (PDMS)/single-wall carbon nanotube (SWCNT)/silver-coated nickel (Ag@Ni) nanoparticle (NP) hybrid composite was devised to realize thermally adjustable smart green shielding. In this composite system, 1 M and 3 M of aqueous NaCl, CaCl₂, and KI ILs were mixed with electromagnetic fillers (SWCNT/Ag@Ni) in the PDMS matrix, which revealed a distinct ion concentration-dependent shielding performance. The composite with 3 M KI IL at 100 °C demonstrated a reversible thermally modulated smart green radiation shielding performance of 68.9 dB in the spectrum range of 14.5–20 GHz. Moreover, the composite showed an exceptionally high green index of ∼101 at 100 °C, confirming its excellent thermally modified absorption shielding capability. Additionally, the IL-generated foamed composite architecture exhibited pressure-sensitive on–off switchable shielding capability, making it ideal for applications in advanced RF switches in satellite communications.