Enhanced stretchability of porous PDMS/CIP composites via weak interfacial bonding and their electromagnetic noise suppression properties

The development of wearable devices operated through massive data communication necessitates the use of lightweight, highly efficient stretchable composites to suppress electromagnetic (EM) noise. In this study, highly stretchable porous polydimethylsiloxane (PDMS)/carbonyl iron powder (CIP) composite-based EM noise suppressors were explored. The porous structure reduced the volume fraction of PDMS in the composites, leading to a reduction in the total weight of the composites. The introduction of CIP to porous PDMS initially degraded stretchability owing to stress concentration at the strongly bonded interfaces between the CIP surface and PDMS. However, reducing the interfacial bonding strength by removing the SiO2 layer on the CIP surface significantly enhanced stretchability, causing the resulting composite to display 1.2–1.6 times higher rupture strain values at the same CIP loading contents than those with high interfacial bonding strength. The EM absorption properties of the porous and nonporous PDMS/CIP composites were characterized, and the porous PDMS/CIP composites exhibited ∼1.5 times higher EM noise suppression performance than the nonporous composites. This improvement is attributed to the vacant space within the porous framework filled with air, which enhances impedance matching and extends the transmission route of EM waves.