Miniaturized Hard Carbon Nanofiber Aerogels: From Multiscale Electromagnetic Response Manipulation to Integrated Multifunctional Absorbers

• Published in: Advanced functional materials 2024-11, Vol.34 (48), p.n/a
• Main Authors: Shao, Gaofeng, Xu, Rupan, Chen, Yu, Yu, Gaoyuan, Wu, Xiaodong, Quan, Bin, Shen, Xiaodong, Huang, Xiaogu
• Format: Article
• Language: English
• Subjects: Aerogels; Broadband; Carbon fibers; Electromagnetic properties; Freezing; hard carbon; Hydrophobicity; Impedance matching; Microspheres; Microwave absorption; Microwave attenuation; miniaturized aerogels; multiple functionalities; multiscale structural engineering; Nanofibers; Polysilsesquioxanes; Self-assembly; Structural engineering; Thermal insulation; Thermal resistance
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202408252

The multiscale structural engineering strategy presents a powerful method for tailoring the structural attributes of materials at various levels, enabling the flexible control and manipulation of their electromagnetic properties. Nonetheless, orchestrating the multiscale architecture of polymer‐derived carbon aerogels specifically for microwave absorption poses significant challenges. Herein, aramid‐derived hard carbon nanofiber aerogel microspheres (CNFAMs) featuring a hierarchical skin‐core structure are fabricated through a wet‐spinning technique, combined with reprotonation‐mediated self‐assembly and carbonization processes. The presence of large‐scale voids between neighboring microspheres and the microscale porosity within the microspheres themselves improves impedance matching and promotes microwave reflection and scattering. The distinct graphitic domains and defects serve as pivotal elements for conduction and polarization losses, significantly impacting microwave attenuation. By meticulously tailoring the macroscale dimensions, microscale porous architecture, and nanoscale domains, the optimized CNFAMs demonstrate a remarkable absorption bandwidth of 9.62 GHz at an ultralow filling of 0.97 wt%. Additionally, the implementation of application‐oriented microwave absorption through the innovative integration of polysilsesquioxane‐CNFAMs in a host–guest aerogel is explored. This composite system brings together broadband absorption, superhydrophobicity, thermal insulation, resistance to freezing, and robust tolerance to harsh environments. Such a multifaceted approach is designed to tackle the growing challenges associated with complex electromagnetic environments effectively. The multiscale structural engineering strategy finely tailors materials to manage electromagnetic properties effectively. Newly designed hierarchical aramid‐derived carbon nanofiber aerogel microspheres crafted through wet‐spinning, self‐assembly, and carbonization, achieving a notable absorption bandwidth of 9.62 GHz with minimal material use. Integrating them into polysilsesquioxane host–guest systems enhances specific applications, offering superhydrophobicity and thermal insulation, thus effectively navigating complex electromagnetic environments.