Page 118 - Read Online

Hao et al. Soft Sci. 2025, 5, 39 https://dx.doi.org/10.20517/ss.2025.48 Page 17 of 25

[107]
mechanisms . As shown in Figure 6A, the composite material exhibited remarkably robust
electromagnetic wave absorption performance, even as its impedance matching worsens with rising
[108]
temperature .

The spatial arrangement of functional units within the matrix represents a critical parameter for tailoring
multiple reflection-scattering mechanisms. Different arrangement patterns can drastically alter
electromagnetic wave propagation paths and interaction mechanisms within the material. When functional
units are arranged in an ordered manner, such as in a regular array, electromagnetic waves encounter
periodically arranged functional units during propagation. This periodic structure induces special scattering
and interference effects on the electromagnetic waves. Under certain specific incident angles and
frequencies, ordered functional units can form Bragg scattering, causing electromagnetic waves of specific
frequencies to be strongly reflected or scattered, thereby achieving absorption of electromagnetic waves in
specific frequency bands. Zhang et al. fabricated titanium nitride/zirconium oxide/carbon (TiN/ZrO /C)
2
ternary nanofiber membranes and incorporated them as mesoscale functional units into a PDMS matrix .
[108]
As revealed by Computer Simulation Technology (CST) simulation results [Figure 6B], the three distinct
distribution patterns exhibited markedly different electromagnetic wave reflection behaviors in the
metacomposite. The 3 × 3 ordered arrangement yields the highest intra-composite wave reflection, enabling
the metacomposite to achieve a minimum RL of -51.7 dB at 453 K with an effective absorption bandwidth
of 2.3 GHz.

Similarly, Chen et al. synthesized three microsphere types with different dielectric properties and
constructed absorbers featuring distinct stacking architectures . Upon entering the composite absorber,
[109]
electromagnetic waves undergo interlayer multiple reflection-scattering, extending their propagation path
and time. Partial waves reflect at dielectric layer interfaces, while the remaining penetrate to subsequent
layers, creating interference between reflected waves that promotes energy dissipation. As shown in
Figure 6C, the C-HC-C (C and HC represent microspheres with different dielectric properties) stacked
model displayed the highest absorption amplitude, attributed to optimized structure and prolonged wave-
[109]
matter interaction . Li et al. constructed graphene-based aerogel microspheres (GAM) with hollow and
[114]
core-shell structures . Simulations of various layered structures of GAM arranged in single/double-layer
arrays were conducted to investigate the group coupling effects on microwave absorption performance
through synergistic absorption, interference, and resonant attenuation mechanisms . As shown in the
[114]
electric field distribution intensity maps [Figure 6D], double-layer GAM arrays significantly broaden the
electromagnetic response range compared to single layers, attributed to the synergistic reaction of the
second array that enhances scattered wave multiplicity and intra-array oscillations. Additionally, with the
introduction of the double-layer structure, the volume loss density of double-layered heterogeneous GAMs
(DTGAM) and hollow GAMs (HGAM) significantly increases. Multi-layer structures can cause gradient
impedance mismatches, leading to reflections and scattering between different layers, thereby producing
cancellation effects.

In addition to ordered array arrangements, disordered arrangements of functional units also have unique
advantages. Disordered arrangements can disrupt the regularity of electromagnetic wave propagation,
causing electromagnetic waves to undergo more random reflections and scatterings within the
material [115-117] . This random reflection and scattering process can broaden the absorption frequency band,
enabling it to absorb electromagnetic waves across a wider frequency range. Recently, researchers have
investigated the differences in electromagnetic wave reflection between structures exhibiting disordered
distributions and those with ordered periodic arrangements. The findings reveal that the reflection phase of
super-uniform and disordered structures demonstrates a more non-uniform distribution. The operational