Highly-controlled synthesis of organic layers on mesoporous silica: their structure and application to toxic ion adsorptions
Highly-controlled synthesis of organic layers on mesoporous silica: their structure and application to toxic ion adsorptions
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DOI：
10.1039/b504957a
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发表时间：
2005-08
影响因子：
3.3
通讯作者：
H. Yoshitake
中科院分区：
文献类型：
--
作者：
H. Yoshitake
自从有序介孔二氧化硅被发现以来，在介观水平上控制有机层的结构已经成为二氧化硅表面改性的一个越来越感兴趣的课题。此外，表面官能团的微观结构也产生了介孔二氧化硅特有的新问题。我们在这个领域的兴趣在于揭示在合成改性介孔二氧化硅以获得均匀结构方面的潜在问题，开发新的合成路线以获得高官能化的固体，并阐明它们作为吸附剂的作用机理。所有这些目标都将在介观和微观尺度上描述。先期硅烷合成与后表面改性的比较主要与官能团分子结构的均一性有关。另一方面，比较接枝和直接共缩合的差异往往归因于有机基团分散的一致性。详细讨论了官能团的密度，特别是介观均匀度、分散方法(通过改变每个有机链或单位表面积的官能团数目和改变进行改性的合成阶段)和固体上的分布。精制的直接共缩合方法，即与模板相关的官能化，在暴露所有官能团以及选择性修饰内孔表面方面具有几个优点。离子吸附性能与合成方法的选择、吸附位置的微小差异和中孔骨架结构的不同有关。
Since the discovery of ordered mesoporous silica, control of the structure of organic layers at the mesoscopic level has become a topic of growing interest for the modification of silica surfaces. In addition, the microstructure of functional groups on the surface also produces new problems specific to mesoporous silica. Our interest in this field consists in revealing potential problems in the synthesis of modified mesoporous silica for achieving a uniform structure, developing new synthetic routes to highly-functionalized solids and elucidating the mechanism where they work as an adsorbent. All these objectives will be described both on the mesoscopic and microscopic scales. The comparison of in-advance silane synthesis with post on-surface modification is related mainly to the uniformity in the molecular structure of the functional groups. On the other hand, the differences emerging from the comparison between grafting and direct co-condensation are often attributed to the uniformity in the dispersion of the organic groups. The density of the functional groups, which is often regarded as an important specification of the material, is discussed in detail, especially in terms of the mesoscopic uniformity, the method of dispersion (explored by changing the numbers of the functional groups per organic chain or per unit surface area and by changing the stage of synthesis where the modification is carried out) and the distribution on the solid. A refined direct co-condensation method, functionalization associated with templating, has several advantages in the exposure of all functional groups as well as in selective modification of the internal pore surface. The performance of ion adsorption is discussed in relation to the structural differences caused by the choice of synthetic method, small differences in the adsorption sites and the mesopore framework structures.