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Journal of Inorganic Materials

Journal of Inorganic Materials

   

Compressive Resilience Mechanism of SiO2 Nanofibre Aerogels

LI Fuping1,2, CHU Jiabao1,2, QIU Haibo1,2, DANG Wei1,2, LI Chenxi1,2, ZHAO Kang1,2, TANG Yufei1,2   

  1. 1. College of Materials Science and Technology, Xi'an University of Technology, Xi’an 710048, China;
    2. Shaaxi Province Key Laboratory of Corrosion and Protection, Xi'an University of Technology, Xi’an 710048, China;
  • Received:2025-01-25 Revised:2025-03-18
  • About author:LI Fuping (1985-), Associate Professor. E-mail: lifp@xaut.edu.cn
  • Supported by:
    National Natural Science Foundation of China (53404411, 52172074, 51904242); Scientific Research Program Funded by Shaanxi Provincial Education Department (23JC056)

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Abstract: SiO₂aerogels possess low density, ultralow thermal conductivity and excellent chemical stability, making them suitable for widely application in the fields of aviation and aerospace, building energy conservation, and energy chemical industry. Traditional SiO2 nanoparticle aerogels have large brittleness and poor resilience due to the pearl necklace-like particle structure. Using nanofibers as construction units to fabricate SiO₂ nanofiber aerogels can overcome the brittleness and improve the resilience. However, the resilience mechanism of SiO₂ nanofiber aerogels is still unclear. In the present work, flexible SiO2 nanofibers were prepared by electrospinning. And the effect of calcination temperature on phase microstructure and flexibility was systematically investigated to elucide flexibility mechanism. Subsequently, SiO₂ nanofiber aerogels were fabricated by freeze drying. The influence of solid content on the pore structure, strength and resilience of aerogels was thoroughly studied. A buckling deformation model based on effective nanofiber length was established to elucidate the compressive resilience mechanism. The findings show that calcination temperature affects the amorphous structure and flexibility of SiO₂ nanofibers. The degree of short-range order in SiO₂ increases with the increase in calcination temperature, leading to poor flexibility of nanofibers. The resilience of SiO₂ nanofiber aerogels is related to solid content. The energy loss coefficient and resilient rate of aerogels fabricated with 0.5 wt.% solid content(in mass) are 0.6 and 55.2%, respectively. The resilience of SiO₂nanofiber aerogels is dominated by effective nanofiber length and the curvature radius of nanofibers. Their relationship of resilience model is established and proved through nanofiber buckling theory. With a reduction in curvature radius, achievable through the enhancement of nanofiber flexibility, and an increase in effective nanofiber length, the compressive resilient rate of aerogels increases. The present work provides theoretical guidance for the design of SiO₂nanofiber aerogels with high resilience.

Key words: nanofibres, flexibility, aerogel, resilience mechanism