航空学报 > 2011, Vol. 32 Issue (5): 941-947   doi: CNKI:11-1929/V.20101213.1757.012

溶胶共凝法制备准连续密度梯度SiO2气凝胶

归佳寅, 周斌, 钟艳红, 杜艾, 沈军   

  1. 同济大学 上海市特殊人工微结构材料与技术重点实验室, 上海 200092
  • 收稿日期:2010-07-20 修回日期:2010-10-18 出版日期:2011-05-25 发布日期:2011-05-19
  • 通讯作者: Tel.: 021-65980228 E-mail: zhoubin863@tongji.edu.cn E-mail:zhoubin863@tongji.edu.cn
  • 作者简介:归佳寅(1986- ) 男,硕士。主要研究方向:气凝胶类材料。 Tel: 021-65982762 E-mail: guijy@126.com 周斌(1970- ) 男,博士,教授,博士生导师。主要研究方向:纳米材料。 Tel: 021-65980228 E-mail: zhoubin863@tongji.edu.cn
  • 基金资助:

    国家自然科学基金青年基金(50802064); 高等学校博士学科点专项科研基金(20090072110047);上海市科委纳米专项(0952nm00900)

Fabrication of Graded Density SiO2 Aerogel via Sol-Co-Gelation Techniques

GUI Jiayin, ZHOU Bin, ZHONG Yanhong, DU Ai, SHEN Jun   

  1. Shanghai Key Laboratory of Special Microstructure Materials and Technology, Tongji University, Shanghai 200092, China
  • Received:2010-07-20 Revised:2010-10-18 Online:2011-05-25 Published:2011-05-19

摘要: 针对气凝胶在航空航天领域的应用需求,为了进一步拓展单一密度气凝胶的应用范围,对密度梯度SiO2气凝胶的制备进行了研究。采用自建密度梯度制备成型装置,以正硅酸乙酯为有机硅源,经溶胶共凝工艺,结合CO2超临界干燥技术,获得密度范围在60~160 mg/cm3的准连续密度梯度SiO2气凝胶。采用光学显微镜、扫描电子显微镜、X射线相衬成像等手段对制备获得的SiO2气凝胶进行测试表征。通过与逐层凝胶法制备的密度渐变SiO2气凝胶进行对比发现,溶胶共凝工艺消除了层间界面处所产生的致密层和密度突变,有利于相邻两层间的互扩散,使密度变化更趋于连续。采用该法制备的密度梯度气凝胶拓展了常规气凝胶的应用范围,在声阻抗匹配和空间粒子捕获等领域有潜在的应用前景。

关键词: 溶胶共凝, 准连续气凝胶, 密度梯度, 逐层凝胶, 互扩散

Abstract: For the application requirement in aerospace and further expanding the application field of aerogel, the fabrication of gradient density aerogel SiO2 has been researched in this paper. By a self-built device, a continuously graded silica aerogel is fabricated via special sol-co-gelation techniques, with tetraethoxysilane (TEOS) as the organic precursor and by a supercritical drying process. Its density ranges from 60 mg/cm3 to 160 mg/cm3. Scan electron microscope, X-ray phase contrast method and optical microscopy are used to characterize the graded density silica aerogel prepared. Compared with the graded density silica aerogel produced by layer-by-layer gelation techniques, the sol-co-gelation techniques smooth out density mutation and increase the interdiffusion between adjacent layers, which makes density change tend to be more continuous. The gradient density aerogel fabricated by such a method expands greatly the application of conditional aerogel. It can potentially be used in many fields such as acoustic impedance matching and interstellar particles collection.

Key words: sol-co-gelation, continuous aerogel, graded density, layer-by-layer gelation, interdiffusion

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