Meslostructured silica supports for functional materials and molecular machines
Meslostructured silica supports for functional materials and molecular machines
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DOI：
10.1002/adfm.200601217
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发表时间：
2007-09-24
影响因子：
19
通讯作者：
Zink, Jeffrey I.
中科院分区：
文献类型：
--
作者：
Angelos, Sarah;Johansson, Erik;Zink, Jeffrey I.
介孔结构的二氧化硅薄膜和颗粒由表面模板溶胶-凝胶技术制备的功能材料的形成高度通用的衬底。在纳米结构的特定空间分离区域中故意放置具有雌激素活性的分子的能力是这些材料的重要特征。这种放置利用了利用二氧化硅框架和模板化孔之间的物理和化学差异的策略。作为分子对的放置的实例，供体和受体分子可以靶向介观结构化薄膜的不同区域，并且可以测量它们之间的能量转移。结果不仅显示了空间分离，而且还被用作分子标尺来测量它们之间的平均距离。介孔结构的二氧化硅也是分子机器的优良载体。当附着在二氧化硅上时，经历大幅度运动的分子在被光、电（氧化还原）和化学（pH、竞争性结合）能量激活时可以起到叶轮和纳米阀的作用。衍生的偶氮苯分子，通过使用放置策略之一附着到孔壁，起到叶轮的作用，可以移动其他分子通过孔。轮烷和伪轮烷，放置在孔入口处，作为看门人，可以捕获和释放分子时，刺激的孔。在介观结构的二氧化硅表面和内部有意地放置功能分子，为纳米尺度的基础研究和纳米材料的制备提供了许多可能性。在流体学、生物药物递送和控制释放等不同领域的应用。
Mesostructured silica thin films and particles prepared by surfactant-templated sol-gel techniques are highly versatile substrates for the formation of functional materials. The ability to delibarately place molecules possessing estre activities in specific spatially separated regions of the nanostructure is an important feature of these materials. Such placement utilizes strategies that exploit the physical and chemical differences between the silica framework and the templated pores. As an example of placement of pairs of molecules, donor and acceptor molecules can be targeted to different regions of mesostructured thin films and energy transfer between them can be measured. The results not only demonstrate the spatial separation but also are used as a molecular ruler to measure the average distance between them. Mesostructured silica is also an excellent support for molecular machines. Molecules that undergo large amplitude motion, when attached to the silica, can function as impellers and nanovalves when activated by light, electrical (redox) and chemical (pH, competitive binding) energy. Derivatized azobenzene molecules, attached to pore walls by using one of the placement strategies, function as impellers that can move other molecules through the pores. Rotaxanes and pseudorotaxanes, placed at pore entrances, function as gatekeepers that can trap and release molecules from the pores when stimulated. Deliberately placed functional molecules on and in mesostructured silica offer many possibilities for both fundamental studies on the nanoscale and for. applications in fields as diverse as fluidics, biological drug delivery and controlled release.