image: The incorporation of Co and Ti significantly facilitated the nanostructuring of the fibers and enhanced the dielectric loss of the fiber films. With only a 5 wt% fiber filling content, CTS-800 demonstrates excellent microwave absorption properties, including strong absorption (minimum reflection loss, RLmin: -66.0 dB), a thin thickness (2.5 mm), and an impressive effective absorption bandwidth (EAB: 8.64 GHz). Additionally, the nanostructuring of the fibers and the three-dimensional network structure imparted by electrospinning facilitated the conduction and dissipation of external stress and heat. Herein, CTS-800 is a multifunctional composite material that integrates excellent microwave absorption performance, flexibility, compressive resilience, customizable properties, and thermal insulation. The successful preparation of such multi-functional nanofiber mats makes it promising perspectives for the application of thermal and microwave protection.
Credit: Journal of Advanced Ceramics, Tsinghua University Press
The rapid advancements in the electronics industry have provided significant convenience to the civilian uses but have also contributed to electromagnetic pollution, posing risks to human safety. To meet the diverse requirements of civilian applications, such as devices with varied curved surfaces and clothing for different working environments, EMW absorbers must not only provide effective absorption but also be lightweight, easily processed, and sufficiently flexibility. Additionally, EMW absorption materials face challenges under extreme conditions commonly encountered in construction and transportation industries, including high temperatures, frequent vibrations, and pressure impacts.
Hence, exploring the materials with exceptional thermal insulation, significant flexibility and resilience, excellent processability, and ultralight characteristics represents a trend in the development of advanced microwave absorbers. Polymer-derived ceramic (PDC) SiOC exhibits robust mechanical and high-temperature performance in extreme environments, combined with low density, high strength, and low raw material costs, which highlight its potential for applications in both thermal and electromagnetic wave (EMW)protection.
However, SiOC ceramics derived from a single precursor polymer suffer from low dielectric properties, limiting their further applications. To improve EMW attenuation performance, it is common to introduce a second phase into the SiOC matrix, leveraging the advantages of various components to enhance the EMW absorption.
On the other hand, the inherent brittleness of SiOC ceramics severely hinders their use in complex environments. In this case, electrospinning is a versatile method for producing one-dimensional micro-nanofiber materials with uniform size distribution and consistent morphology. Aiming to improve both flexibility and EMW absorption performance, the strategy of multi-phase composition and electrospinning were applied to fabricate SiOC nanofibers
The team published their work in Journal of Advanced Ceramics on September 9, 2024.
Herein, Co and TiO2 modified SiOC nanofibers (CTS) were successfully prepared using a simple and controllable electrospinning technique. Thanks to the excellent three-dimensional continuous network structure provided by electrospinning and the uniform distribution of composite materials within the fibers, CTS composites exhibit outstanding thermal insulation (thermal conductivity <0.0404 Wm-1K-1), remarkable flexibility (less than 4% resistance change after 1500 cycles of 180° bending), and impressive compressive resistance (residual strain <12% after 500 cycles at 60% strain). The CTS-800 sample (silicone resin) with a filler content of only 5 wt% achieves an effective absorption bandwidth (EAB) of 8.64 GHz (9.36-18.00 GHz) at a thickness of 3.25 mm, with an RLmin value of -66.00 dB at 17.11 GHz. The successful preparation of such multi-functional CTS nanofiber materials makes it promising perspectives for the application of thermal and microwave protection.
The SiOC nanofiber sample exhibits the comprehensive multifunctional properties due to its high porosity and multilayer structure along the thickness. EMW or thermal shock waves from the outside can be significantly attenuated. Additionally, outstanding flexibility ensures that our findings can perfectly grapple with the deformations required in various high-demand scenarios, thus enhancing work efficiency.
About Author
Prof. Lixi Wang is the deputy dean of the College of Materials Science and Engineering at Nanjing University of Technology. She holds the BSc, M.S. and Ph.D. in materials science from Nanjing Tech University (2000-2009), and later became a visiting scholar at Georgia Institute of Technology in 2012., where focusing on research and teaching in optical functional materials. Prof Lixi Wang’s research has been concentrated on electromagnetic functional and spectral conversion materials.
Prof. Yi Hou holds the BSc and Ph.D in materials science from Northwestern Polytechnical University (2009-2019). He became the Associate Scientist/Research Scientist in Temasek Laboratories’ at National University of Singapore from 2018 to 2022. Prof Yi Hou is working on microwave absorption materials and ceramic nanofiber materials.
Mr. Linghao Pan is a master graduate student of College of Materials Science and Engineering at Nanjing University of Technology. His research focuses on SiOC nanofiber materials.
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen. JAC’s 2023 IF is 18.6, ranking in Top 1 (1/31, Q1) among all journals in “Materials Science, Ceramics” category, and its 2023 CiteScore is 21.0 (top 5%) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
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Journal
Journal of Advanced Ceramics
Article Title
Flexible and resilient Co/TiO2/SiOC nanofibers via electrospinning: Towards thermal and electromagnetic wave protection
Article Publication Date
9-Sep-2024