The rapid advancement of electronic communication technology has greatly aided human productivity and quality of life, but it has also resulted in significant electromagnetic pollution issues. Traditional metals and alloys are often used for electromagnetic interference (EMI) shielding due to their excellent electrical conductivity. However, they have drawbacks such as being heavy, expensive, and having low corrosion resistance, which limits their application in electromagnetic shielding. Therefore, it is crucial to develop novel EMI shielding materials. Polymers, being highly flexible, corrosion-resistant, and possessing high specific strength, are frequently employed in electromagnetic shielding materials. In this review, we firstly introduce the basic theory of electromagnetic shielding. Then, we outline the processing methods and recent developments of polymer-based electromagnetic shielding composites, including uniform-, foam-, layered-, and segregated structures. Lastly, we present the challenges and prospects for the field, aiming to provide direction and inspiration for the study of polymer-based electromagnetic shielding composite materials.

Electromagnetic radiation and its associated secondary pollution significantly disrupt the proper functioning of electronic devices and may even pose a threat to human health. Therefore, the design of absorption-dominated electromagnetic shielding materials is of paramount importance. In this study, ethylene propylene diene monomer (EPDM) and polyolefin elastomer (POE) were used as the matrix materials, while carbon black (CB), carbon nanotubes (CNTs), and ferric oxide (Fe₃O₄) were used as fillers. The composite foams with dual loss mechanisms and porous structures were prepared by hot press foaming. The foam exhibits high electromagnetic interference shielding efficiency (EMI SE) and an absorption-dominated shielding mechanism. The dual loss mechanisms consist of dielectric loss from CB and CNTs, and magnetic loss from the incorporation of Fe₃O₄, which mitigates the impedance mismatch between the material and space, thereby enhancing electromagnetic wave absorption. Consequently, the composite foam demonstrates an optimal EMI shielding effectiveness of 34 dB and an absorption coefficient of 0.58, thereby confirming a shielding mechanism dominated by absorption. Moreover, the composite foam exhibits excellent mechanical properties, elastic recovery, shielding durability, and thermal stability, making it well-suited for both conventional environments and potential long-term use in complex and extreme conditions.

High-performance pressure sensors provide the necessary conditions for smart shoe applications. In this paper, the elastic Macroporous Graphene Aerogel (MGA) was synthesized via the modified Hummers’ method, and it was further combined with Expanded-Thermoplastic polyurethane (ETPU) particles to assemble MGA-ETPU flexible sensors. The MGA-ETPU has a low apparent density (3.02 mg/cm³), high conductivity (0.024 S/cm) and fast response time (50 ms). The MGA-ETPU has a large linear sensing range (0–10 kPa) and consists of two linear regions: the low-pressure region (0 to 8 kPa) and the high-pressure region (8 to 10 kPa), with sensitivities of 0.08 kPa⁻¹, and 0.246 kPa⁻¹, respectively. Mechanical test results show that the MGA-ETPU sensor showed 19% reduction in maximum stress after 400 loading–unloading compression cycles at 40% strain. Electrical performance tests showed that the resistance of MGA-ETPU sensor decreased by 12.5% when subjected to sudden compression at 82% strain and returned to its original state within 0.05 s. Compared to existing flexible sensors, the MGA-ETPU sensors offer excellent performance and several distinct advantages, including ease of fabrication, high sensitivity, fast response time, and good flexibility. These remarkable features make them ideally suited as flexible pressure sensors for smart shoes.

An interconnected sponge structure and porous surface poly (acrylonitrile-co-methyl acrylate) (P(AN-MA)) microfiltration membranes (MF) were fabricated via thermally induced phase separation (TIPS) by using caprolactam (CPL), and acetamide (AC) as the mixed diluent. When the ternary system was composed of 15 wt.% P(AN-MA), 90 wt.% CPL, and 10 wt.% AC and formed in a 25 °C air bath, the membrane exhibited the highest water flux of 8107 L/m²·h. The P(AN-MA) membrane contained hydrophobic groups (-COOCH₃) and hydrophilic groups (-CN), leading it to exhibit oleophobic properties underwater and hydrophobic properties in oil. The membrane demonstrates efficient separation of immiscible oil/water mixtures. The pure water flux of the petroleum ether/water mixture measured 870 L/m²·h, and the pure oil flux of the petroleum tetrachloride/water mixture measured 1230 L/m²·h under the influence of gravity. Additionally, the recovery efficiency of diluents through recrystallization was 85.3%, significantly reducing potential pollution and production costs.

Developing electromagnetic interference (EMI) shielding materials with high absorption capability is an effective strategy to mitigate electromagnetic radiation and the associated secondary electromagnetic pollution. Herein, a Janus asymmetric EMI shielding composite based on an ethylene propylene diene monomer (EPDM)/polyolefin elastomer (POE) matrix is constructed, and electromagnetic functional partitioning is realized via a facile lamination–vulcanization process. The composite integrates EPDM/POE/Fe₃O₄@thermally expandable microsphere (TEMs) foam as the absorbing layer and a highly conductive EPDM/POE/carbon nanotubes (CNTs)/carbon black (CB) layer as the reflective backing, thereby establishing a gradient impedance-matching interface and a multistage “absorb–reflect–reabsorb” attenuation pathway. Under absorbing-side incidence, the composite exhibits absorption-dominant “green” shielding, delivering an average total EMI shielding efficiency (SE_T) of ∼40.00 dB in the X-band with a high absorptivity (A ≈ 0.82). Benefiting from a robust crosslinked elastomer network, the composite maintains a stable mechanical response and shielding durability after 500 compression cycles at 60% strain, with SE_T decreasing only slightly from ∼40.00 dB to 37.42 dB. Moreover, rapid and reversible Joule heating with a spatially uniform temperature distribution is achieved at low voltages (3 V). Overall, we offer a feasible strategy for fabricating flexible, compressible, low-reflection, and durable EMI shielding materials in this study.

Rapid communication and electronics growth demands multifunctional polymer composites with EMI shielding, wave absorption, thermal/electrical insulation and lightweight properties.