Self-assembly of alkyl-substituted cubic siloxane cages into ordered hybrid materials.
Self-assembly of alkyl-substituted cubic siloxane cages into ordered hybrid materials.
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DOI：
10.1002/chem.200801106
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发表时间：
2008-09
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影响因子：
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通讯作者：
Atsushi Shimojima;Ryota Goto;N. Atsumi;K. Kuroda
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文献类型：
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作者：
Atsushi Shimojima;Ryota Goto;N. Atsumi;K. Kuroda
通过由立方硅氧烷头和疏水性烷基尾组成的新型两亲分子的自组装，合成了具有良好有序介观结构的硅氧烷-有机杂化物。用乙氧基官能化的单烷基前体（C（n）H（2n+1）Si（8）O（12）（OEt）（7），1 Cn，n=16，18和20）在酸性条件下水解，保留硅氧烷笼，导致通过蒸发诱导自组装过程形成二维六方相。对这些杂化介观结构的固态（29）Si MAS NMR谱的分析证实了立方硅氧烷单元交联形成硅氧烷网络。煅烧这些混合物得到介孔二氧化硅，其孔径取决于烷基链的长度。我们还发现，具有两个烷基链的前体形成层状相，从而证实每个笼的烷基链的数量对介观结构有很强的影响。这些结果通过明确定义的低聚硅氧烷基前体的自组装扩展了新型纳米混合和纳米多孔材料的设计可能性。
Siloxane-organic hybrids with well-ordered mesostructures were synthesized through the self-assembly of novel amphiphilic molecules that consist of cubic siloxane heads and hydrophobic alkyl tails. The monoalkyl precursors functionalized with ethoxy groups (C(n)H(2n+1)Si(8)O(12)(OEt)(7), 1 Cn, n=16, 18, and 20) were hydrolyzed under acidic conditions with the retention of the siloxane cages, leading to the formation of two-dimensional hexagonal phases by evaporation-induced self-assembly processes. Analysis of the solid-state (29)Si MAS NMR spectra of these hybrid mesostructures confirmed that the cubic siloxane units were cross-linked to form siloxane networks. Calcination of these hybrids gave mesoporous silica, the pore diameter of which varied depending on the alkyl-chain length. We also found that the precursors that had two alkyl chains formed lamellar phases, thus confirming that the number of alkyl chains per cage had a strong influence on the mesostructures. These results expand the design possibility of novel nanohybrid and nanoporous materials through the self-assembly of well-defined oligosiloxane-based precursors.