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Page 20 of 25 Liu et al. Soft Sci. 2025, 5, 7 https://dx.doi.org/10.20517/ss.2024.69

In summary, polymer-based EMW absorbing materials offer advantages due to their lightweight, flexibility,
easy processing, low cost, and resistance to corrosion. They can easily achieve impedance matching and
optimized conductivity. Intrinsically conductive polymers have good dielectric properties, often acting as a
dielectric component to synthesize multi-component EMW absorbing composites. They can release EM
energy by current and polarization loss. In order to construct high-performance EMW absorbers,
conductive polymers cooperate with other materials to obtain several loss mechanisms. Insulating polymers
are often used to combine with electrically conductive fillers to obtain excellent shielding performance and
tunable electrical properties. The conductive fillers are joined to one another to create a conductive channel.
To further enhance EMI shielding and absorption, the conductive fillers can serve as either dielectric or
magnetic loss materials. Composites based on thermoplastics have good plasticity and processability in the
preparation of EMW absorbing materials. However, their poor thermal resistance limits their application in
high temperatures and long-term exposure to EM. Composites based on thermosetting plastics are brittle
and cannot be molded repeatedly, but they have strong heat resistance, high hardness and strength, and
often have good stability and durability when used as EMW absorbing materials.

CONCLUSION AND OUTLOOK
Advanced polymer-based EMW absorbers that can satisfy the requirements of high-absorbing ability,
tunable EM properties, strong RL, wide EAB, low filler loading, thin thickness, and lightweight have become
a research hotspot. To achieve these goals, the magnetic/dielectric loss and impedance matching of
polymer-based EM absorption materials can be maximized by cooperating with multi-components,
adjusting the structure, and introducing heterogeneous engineering.

Heterointerface engineering strategy introduces various defects including heteroatom doping, vacancies,
dislocations, and twinning. The interfacial polarization generated by the heterointerfaces optimizes the
impedance matching and dielectric loss. The structure design strategy determines the intrinsic loss
capacities, conductive networks and conductive loss, and interfacial effects of polymer-based absorbers.
Many absorbers based on conductive polymers (such as PANI and PPy) and insulating polymers (such as
PDMS, EP, PU, and PVDF) have achieved desirable EMW absorption performance through a combination
of multi-components, structural design and heterointerface engineering strategies.

However, emerging cutting-edge industries and the military have raised higher requirements for EMW
absorbing materials. Developing polymer-based EMW absorption composites with increased matrix area
and the contacting area between multi-components, thus obtaining larger heterogeneous interfaces, is a
worthwhile research topic. Moreover, it is necessary to have a clear understanding of controlling of
conductive phase structure, size, shape, even distribution and the interaction of multi-phase interfaces. The
effects of porosity on the conductivity, the dielectric permittivity and EMW absorption need further study.
The methods for optimizing the microstructure and geometric shape of each layer of polymer-based EMW
absorption materials also need to be studied in detail. Therefore, a more comprehensive strategy combining
theoretical computations and experimental research is required to gain deeper insights into the
relationships between the structure and properties of polymer-based EMW.

In addition, the development of polymer-based EMW absorption materials with multifunctionalities such as
heat conductivity, fire retardancy, joule heating or photothermal properties has practical significance.
Furthermore, there is a need to develop multispectral stealth materials capable of simultaneously addressing
microwave, infrared, and visible bands.