Thermally tunable ethanol impregnated PDMS/CoZTO/SWCNT composite architecture for smart electromagnetic shielding

Abstract

Shape memory elastomer composites with externally stimulated shielding capability are greatly sought to protect high-end artificial intelligence-based electrical and telecommunication devices in the military, aerospace, robotics, etc., from electromagnetic interference (EMI). However, the fabrication of such composites integrated with externally responsive green EMI shielding capabilities is promising but greatly challenging. Herein, ethanol (thermally active phase) mixed polydimethylsiloxane (PDMS)/single wall carbon nanotube (SWCNT)/cobalt doped zinc tin oxide (CoZTO) hybrid composite with an active guest method was devised. This design strategy explores how the thermally controlled liquid-gas phase transition led microstructural modifications regulate the macroscopic shielding features like absorption enhancement and reflection minimization. The composite adapts the 72.18 % volumetric actuation by liquid-to-vapor phase transition of ethanol at 80 °C, promoting the total EMI shielding value up to 48.77 dB from 18.4 dB at 20 GHz due to microstructure induced electromagnetic modifications. Additionally, a green index of 7.2 confirms the absorption dominance over reflection shielding in the studied composite. Furthermore, ethanol-generated foamed architecture of composite offers pressure-sensitive on-off shielding tunability, which accounts for the potential use in manufacturing advanced RF switches.