C ZHANG, Taoyan Yang, Yue Wang, Guoliang Li, Liangqiang Wei, Tianliang Zhai
The growing reliance on wireless electronic devices and future mobility has driven demand for electromagnetic interference (EMI) shielding solutions that can both shield and absorb electromagnetic waves, especially at higher frequencies. Drawing inspiration from plant transpiration, Janus-structured bilayer aerogel/polydimethylsiloxane nanocomposites (JAPCs) were successfully prepared via a capillary force-driven strategy, exhibiting low-reflection and efficient EMI shielding performance. Through solvent-evaporation-assisted capillary filling, polydimethylsiloxane (PDMS) was fully infiltrated into the bilayer aerogel containing magnetic and conductive nanomaterials and featuring an ordered asymmetric architecture, which was fabricated through a two-step unidirectional freezing process. A uniformly dispersed hollow Fe 3 O 4 microspheres@graphene oxide (HFO@GO) nanohybrid morphology was observed in the magnetic layer of the JAPC, providing favorable impedance-matching performance. A wirelike and entangled carbon nanotube (CNTs) network was observed in the conductive layer. The tubularly oriented structure of this network enables high EMI shielding efficiency. Strong interfacial bonding between the constituent layers of the bilayer aerogel and the resulting JAPC was confirmed by SEM. The compressive strength of the bilayer aerogels increased significantly, rising from 8.0 kPa for a bilayer aerogel to 2.92 MPa for a JAPC at 40% strain. The shielding effectiveness of reflection (SE R ) is significantly lower for incident waves approaching from the magnetic layer compared to the conductive layer. However, the total shielding effectiveness (SE T ) remains nearly invariant regardless of the incident wave direction. The resulting JAPC derived from an ordered bilayer aerogel enables highly effective Ka-band EMI shielding with low reflectivity. It achieves an average SE R of 2.17 dB while maintaining a maximum average SE T of 59.26 dB. Owing to its unique ordered Janus configuration, an “absorption–reflection–reabsorption” attenuation pathway is established, resulting in high overall effective EMI shielding performance with minimized secondary radiation. This work provides an effective strategy for designing high-performance, low-reflection EMI shielding nanomaterials for next-generation high-frequency electronic applications.