物理化学学报 >> 2016, Vol. 32 >> Issue (7): 1727-1733.doi: 10.3866/PKU.WHXB201604082

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SiO2阶层多孔结构搭建及块体材料制备机理

郭兴忠*(),丁力,于欢,单加琪,杨辉   

  • 收稿日期:2016-02-16 发布日期:2016-07-08
  • 通讯作者: 郭兴忠 E-mail:msewj01@zju.edu.cn
  • 基金资助:
    国家自然科学基金(51372225)

Construction and Preparation Mechanism of Hierarchically Porous SiO2 Monoliths

Xing-Zhong GUO*(),Li DING,Huan YU,Jia-Qi SHAN,Hui YANG   

  • Received:2016-02-16 Published:2016-07-08
  • Contact: Xing-Zhong GUO E-mail:msewj01@zju.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51372225)

摘要:

借助溶胶-凝胶结合相分离和模板法进行了阶层多孔结构的搭建及二氧化硅多孔块体材料的制备,表征了阶层多孔块体的显微结构及孔结构特性,分析了阶层多孔结构的搭建机理。研究结果表明,三嵌段共聚物聚环氧乙烷-聚环氧丙烷-聚环氧乙烷(P123)的加入不仅诱导共混体系发生相分离,调控大孔结构的形成,同时形成球形胶束并作为模板剂进入骨架,而1,3,5-三甲基苯(TMB)的加入使P123形成的胶束膨胀且更加稳定,在骨架上成功引入了球形介孔,骨架中凝胶粒子相互聚集形成微孔,从而搭建贯通大孔-球形介孔-微孔同时分布的阶层多孔结构,并获得相应的多孔块体材料;当正硅酸甲酯(TMOS):P123:TMB摩尔比为1:0.015:0.353时,多孔块体材料的阶层多孔结构最优,大孔孔径为0.5-1.5 μm,介孔孔径为3-4 nm,显气孔率66.1%,比表面积为616 m2·g-1

关键词: 溶胶-凝胶, 二氧化硅, 阶层多孔结构, 多孔块体, 模板剂, 胶束膨胀剂

Abstract:

Hierarchically porous SiO2 monoliths were prepared via sol-gel process accompanied by the phase separation and template method. The microstructure and pore structures of the monoliths were characterized, and the formation mechanism of hierarchically porous structures was investigated. The results show that the addition of poly(ethyleneoxide)-block-poly (propyleneoxide)-block-poly (ethyleneoxide) (P123) induces the phase separation to adjust the formation of the macroporous structure, and the spherical P123 micelles are also formed and distributed into the skeletons as templates. The addition of the micelle-swelling agent 1,3,5-trimethylbenzene (TMB) expands and stabilizes the P123 micelles, so that uniform spherical mesopores are successfully introduced into the macroporous framework. Meanwhile, the gel nanoparticles on the skeletons aggregate to form micropores. As a result, the hierarchically porous structures are constructed by well-defined interconnected macropores-spherical mesopores-micropores, and the corresponding porous monoliths are prepared. When the mole ratio of tetramethoxysilane (TMOS) : P123 : TMB is 1 : 0.015 : 0.353, the optimum hierarchical structure is obtained with macropore size of 0.5-1.5 μm, mesopore size of 3-4 nm on the skeleton, apparent porosity of 66.1% and Brunauer-Emmett-Teller (BET) specific surface area as high as 616 m2·g-1.

Key words: Sol-gel, Silica, Hierarchically porous structure, Porous monoliths, Template, Micelle-swelling agent

MSC2000: 

  • O647