Intelligent Off/On switchable electromagnetic wave absorbing material based on VO₂ nanowires

With the development of modern communication devices, the demand for intelligent electromagnetic wave (EMW) absorbing materials that dynamically respond to environmental changes is ever-growing. However, the design and fabrication of high-performance EMW absorbing materials with adapt features remains challenging. Here, we report a temperature-responsive composite comprising VO₂ nanowires (NWs) and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP). Benefiting from the phase transition characteristics of VO₂ and the high aspect ratio of NWs, the composite demonstrates two distinct off/on switchable EMW absorbing performances as the temperature increases at low filler loading of VO₂. The composite with 10 wt% VO₂ NWs transitions from transmission to absorption, showcasing a maximum change in reflection loss (RL) and effective absorption bandwidth (EAB) values of 53.09 dB and 4.85 GHz at the thin thickness of 2.5 mm and 2 mm, respectively. While the composite with 30 wt% VO₂ NWs shows a switch from absorption to reflection with the highest ΔEAB and ΔRL values of 3.59 GHz (1.5 mm) and 44.29 dB (2.5 mm), respectively. Additionally, radar cross-sectional (RCS) simulations verify the intelligent EMW absorbing performance of the composite. The work provides an effective and sustainable approach to harness the potential of VO₂ for developing tunable and high-performance wave-absorbing materials.