3D‐Printed Aerogel Metamaterials with Multiple Heterogeneous Interfaces Enables Integrated Control of Microwave Field, Acoustic Field, and Thermal Field

The Direct‐Ink‐Writing (DIW) 3D‐printed aramid nanofibers (ANF)/carbon nanotubes (CNT)/liquid metal (LM) aerogel metamaterial demonstrates an effective and lightweight strategy to achieve polarization insensitive & ultra‐wideband microwave absorption from 2.65‐18 GHz, broadband noise reduction effect in the 2800‐6400 Hz and thermal suppression capability spontaneously at a low density of only 35 mg/cm3, implying its great potential for multi‐fields involved applications. ABSTRACT In the new generation of communication technologies, intelligent transportation, and energy management and other emerging industrial areas, electromagnetic waves (EMW), acoustics, and thermodynamics coexist in coupled and superimposed forms. Future smart living scenarios require simultaneous mitigation of electromagnetic (EM) interference, noise pollution, and thermal flow impacts. Based on this, this study proposes constructing aerogel metamaterials to achieve integrated regulation of microwave, acoustic, and thermal field. At the microscopic scale, multiple heterogeneous interfaces are formed through the interaction between aramid nanofibers (ANF), carbon nanotube (CNT), and liquid metal (LM). At the macroscopic scale, multi‐stage resonant structures are designed to balance multiple physical fields. The aerogel metamaterial is fabricated via Direct‐Ink‐Writing (DIW) and freeze‐drying. Ultimately, the metamaterial achieves ultra‐wideband microwave attenuation (MA) from 2.65–18 GHz and TE/TM dual‐polarization robustness at oblique incidence approaching 70°; the broadband noise reduction effect in the 2800–6400 Hz; and thermal suppression where the upper surface temperature remains only one‐third of the heating field at 120°C after 30 min. The thermal conductivity of the sample is as low as 0.3649 W/m · K. While the density is only 35 mg/cm3. This study reveals the multi‐physics field cross‐scale synergistic mechanism and provides a new pathway for the integrated multi‐physics field regulation application. The Direct-Ink-Writing (DIW) 3D-printed aramid nanofibers (ANF)/carbon nanotubes (CNT)/liquid metal (LM) aerogel metamaterial demonstrates an effective and lightweight strategy to achieve polarization insensitive & ultra-wideband microwave absorption from 2.65-18 GHz, broadband noise reduction effect in the 2800-6400 Hz and thermal suppression capability spontaneously at a low density of only 35 mg/cm 3, implying its great potential for multi-fields involved applications. ABSTRACT In the new generation of communication technologies, intelligent transportation, and energy management and other emerging industrial areas, electromagnetic waves (EMW), acoustics, and thermodynamics coexist in coupled and superimposed forms. Future smart living scenarios require simultaneous mitigation of electromagnetic (EM) interference, noise pollution, and thermal flow impacts. Based on this, this study proposes constructing aerogel metamaterials to achieve integrated regulation of microwave, acoustic, and thermal field. At the microscopic scale, multiple heterogeneous interfaces are formed through the interaction between aramid nanofibers (ANF), carbon nanotube (CNT), and liquid metal (LM). At the macroscopic scale, multi-stage resonant structures are designed to balance multiple physical fields. The aerogel metamaterial is fabricated via Direct-Ink-Writing (DIW) and freeze-drying. Ultimately, the metamaterial achieves ultra-wideband microwave attenuation (MA) from 2.65–18 GHz and TE/TM dual-polarization robustness at oblique incidence approaching 70°; the broadband noise reduction effect in the 2800–6400 Hz; and thermal suppression where the upper surface temperature remains only one-third of the heating field at 120°C after 30 min. The thermal conductivity of the sample is as low as 0.3649 W / m · K. While the density is only 35 mg/cm 3. This study reveals the multi-physics field cross-scale synergistic mechanism and provides a new pathway for the integrated multi-physics field regulation application. Advanced Science, EarlyView.