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An enormous challenge exists in the achievement of one-dimensional (1D) dielectric carbon composite high-performance microwave absorbents at a low filling ratio. Porous/core− shell dual microstructures have been considered as the potential candidate for designing remarkable microwave absorbers with strong absorption and wide band. Herein, novel multiplestructured tubular carbon nanofibers@TiO 2 (TCNFs@TiO 2 ) hybrids were constructed via the sequential steps of hydrolysis and pyrolysis. The dielectric properties of the as-prepared composites can be tuned by adjusting the relative content of the TiO 2 shell and carbonaceous temperature to enhance the impedance matching behavior. Notably, the minimum reflection loss (RL min ) value reaches up to −61.2 dB with an effective absorption bandwidth (EAB) of 3.2 GHz at 3 mm, and the EAB can cover 5.3 GHz with a thickness of merely 2 mm when 1.3 mL of tetrabutyl titanate (TBT) and 700 °C pyrolysis temperature are optimized, respectively. Delightedly, the mixing ratio is only 10 wt %, outperforming that of the most-related composites. The heterogeneous interfaces in TCNFs−TiO 2 are beneficial for the interfacial polarization relaxation. Besides, the hybrids are enriched with numerous pores to favor the lightweight absorbers. The desirable design in the microstructure can provide a promising route in wide-band and lightweight microwave absorbents.

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Polyimide (PI) aerogels have great potential as filter materials, owing to their unique porous structure and excellent thermodynamic properties. In this work, polyvinylidene fluoride (PVDF) is introduced into the 3D network structure of crosslinked PI by phase separation to prepare PI/PVDF hybrid aerogels. By adding different amounts of PVDF, effective control of the aerogel porous structure is achieved, as a result, the air permeability of the hybrid aerogel is significantly improved while still achieving a filtration efficiency of airborne particulates of more than 99.8%. PVDF is aggregated and dispersed on the surface or inside of the aerogel in the form of nanoparticles, which effectively increases the hydrophobicity of the material. The contact angle of the prepared PI hybrid aerogel is ≈150°, and the water absorption is as low as 2.2%, which enables the aerogel to maintain structural stability in humid environments. In addition, the aerogel exhibits good adsorption effects on organic solvents.

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