Multifunctional electromagnetic interference (EMI) shielding
materials
have become a growing need for modern communication equipment. Nevertheless,
there still remains a challenge in achieving an EMI shielding performance
with high absorption characteristics. Herein, inspired by gravity
induced deposition, the design of a relative distribution of Fe3O4 and a low melting point alloy (LMPA) in poly(vinylidene
fluoride) (PVDF) was achieved by compression molding. Finite element
analysis (FEA) shows that Fe3O4 located in the
upper half of the composite makes incident EMWs rarely reflect on
the surface, and the heterostructure composite has a higher electromagnetic
power loss. Meanwhile, the LMPA dispersed in the lower half of the
composite has synergism with Fe3O4 and achieves
excellent high absorption characteristics through multiple reflections
and absorb–reflect–reabsorb processes. With a thickness
of 2.0 mm, the heterostructure PVDF@Fe3O4/40LMPA
exhibits an excellent EMI shielding effectiveness of 56.26 dB at 10
GHz with an absorption coefficient as high as 0.99999. Additionally,
the excellent photothermal properties and high conductivity of the
composite enable it to have static and dynamic infrared thermal camouflage.
This work provides a strategy for fabricating EMI shielding composites
with excellent absorption characteristics and photothermal properties
for electromagnetic radiation protection and infrared thermal camouflage.