• • The review synthesizes three environmentally adaptive MAM classes—corrosion-protective, anti-icing, and thermal-management—and establishes a unified design logic based on multiscale hierarchical architecture, interfacial polarization engineering, and multifunctional phase integration, while explicitly distinguishing their divergent protection mechanisms (barrier/passivation vs. surface-energy/latent-heat regulation vs. phonon–electron transport decoupling). This comparative framework is the first to map commonalities and distinctions across these three strategies, providing a design roadmap that eliminates redundant trial-and-error in multifunctional absorber development.
• • A critical unresolved trade-off is identified between impedance matching and protective-layer density: dense barrier layers required for corrosion and anti-icing protection inherently degrade microwave absorption by increasing the effective permittivity and reducing the impedance match to free space. The review documents this inverse relationship across representative material systems, establishing it as the central bottleneck for integrated environmental adaptability.
• • The absence of standardized coupled-field test protocols is highlighted as a systemic gap: current characterization methods evaluate electromagnetic absorption, corrosion resistance, anti-icing performance, and thermal management in isolation, failing to capture synergistic or antagonistic effects under simultaneous salt-spray, thermal-cycling, and electromagnetic loading. This lack of protocol standardization prevents cross-study comparability and hinders engineering qualification.
• • Long-term durability data under combined marine salt-spray and thermal-cycling conditions are scarce, with the review noting that most reported systems lack degradation-rate metrics beyond short-term laboratory exposure. This data gap is a primary barrier to technology readiness level advancement and industrial adoption in naval, aerospace, and offshore energy sectors, where service lifetimes of 10–20 years are required.