A colloidal route for delamination of layered solids:: Novel porous-clay nanocomposites
A colloidal route for delamination of layered solids:: Novel porous-clay nanocomposites
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DOI：
10.1002/adfm.200500190
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发表时间：
2006-02-03
影响因子：
19
通讯作者：
Ruiz-Hitzky, E
中科院分区：
文献类型：
--
作者：
Letaïef, S;Martín-Luengo, MA;Ruiz-Hitzky, E
在软条件下，可以通过涉及烷氧基硅烷（例如，乙氧基硅烷），最终得到二氧化硅-粘土异质材料。这些中间体二氧化硅-有机粘土纳米复合材料促进醇盐在水存在下的扩散。水解并随后聚合。该过程是一种异凝聚，其产生均匀的凝胶，其中粘土层堆叠的顺序部分或完全丧失，这取决于层状硅酸盐的性质。在煅烧以消除有机部分（即烷基铵链）之后，得到物不可逆地转化成二氧化硅-粘土材料，其中硅酸盐层被由醇盐产生的二氧化硅网络完全分离。所得固体为无机-无机纳米复合材料，其可与聚合物-粘土纳米复合材料相比，但在本发明的情况下，无机二氧化硅网络为连续相，并且各个层为纳米复合材料的相应分散相。这些材料是具有高比表面积（> 400 m2 g-1）的固体，其表现出微孔性和中孔性。并且还具有两种组分固有的性质，原始粘土（例如，阳离子交换容量）和二氧化硅网络（例如，功能化的能力）。
Under soft conditions, it is possible to cause the irreversible delamination of organoclays (long-chain alkylanimonium cations tetraexchanged smectites, and vermiculite-layered silicate derivatives) via a sol-gel process that involves alkoxysilanes (e.a., ethoxysilane) and that finally gives silica-clay heteromaterials. These intermediate silica-organoclay nanocomposites facilitate the diffusion of the alkoxides which, in the presence of water. are hydrolyzed and subsequently polymerized. This process is a heterocoagulation that gives homogeneous gels in which the order in the layer stacking of clays is partially or completely lost, depending on the nature of the layered silicate. After calcination to eliminate the organic moiety, that is, the alkylammonium chains, the get is irreversibly transformed into a silica-clay material in which the silicate layers are fully separated by the silica network generated by the alkoxide. The resulting solids are inorganic-inorganic nanocomposites which could be compared to polymer-clay nanocomposites, but in the present case the inorganic silica network is the continuous phase and the individual layers the corresponding disperse phase of the nanocomposite. These materials are solids of high specific surface area (> 400 m(2) g(-1)), which exhibit micro- and mesoporosity., and also have properties inherent to both components, the pristine clay (e.g., a cation-exchange capacity) and the silica network (e.g., an ability to be functionalized).