Multi-layered, vertically-aligned and functionalized mesoporous silica films generated by sequential electrochemically assisted self-assembly
Multi-layered, vertically-aligned and functionalized mesoporous silica films generated by sequential electrochemically assisted self-assembly
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DOI：
10.1016/j.electacta.2017.03.220
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发表时间：
2017-05-20
影响因子：
6.6
通讯作者：
Walcarius, Alain
中科院分区：
文献类型：
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作者：
Giordano, Gianmarco;Vila, Neus;Walcarius, Alain
采用多次电化学辅助自组装（EASA）方法制备了多层垂直取向的介孔氧化硅薄膜。这是通过连续的恒电位EASA步骤实现的，这意味着将负电位施加到浸没在含有二氧化硅前体和表面活性剂分子的溶胶溶液中的电极上，该电极被以冲洗电极为目标的开路周期中断，以避免二氧化硅聚集体的沉淀。在每个步骤中产生的氢氧根离子催化表面活性剂模板周围的前体的缩聚和电极表面上的膜生长。多层膜的厚度高达400 nm的获得，表现出良好的有序的六方介观结构的垂直于下面的电极支撑。通过膜，特别是每层之间的质量传输证明了通过循环伏安法使用溶液中的氧化还原探针。此外，这样的多层膜功能化的二茂铁基团共价连接到内部介孔壁表现出远程电子转移的电子跳跃。电荷转移过程可以通过精心制作三明治二氧化硅-二茂铁/二氧化硅-单独/二氧化硅-二茂铁多层膜进行调制，其中绝缘二氧化硅单独作为电子跳跃的屏障。(C)2017爱思唯尔有限公司版权所有
Multilayered and vertically-oriented mesoporous silica films are prepared by multiple electrochemically assisted self-assembly (EASA). This is achieved by consecutive potentiostatic EASA steps, implying the application of a negative potential to an electrode immersed in a sol solution containing silica precursors and surfactant molecules, disrupted by open-circuit periods targeted to rinsing of the electrode to avoid the precipitation of silica aggregates. The generated hydroxyl ions in each step catalyze the polycondensation of precursors around the surfactant template and film growth onto the electrode surface. Multilayered films with thicknesses of up to 400 nm are obtained, exhibiting a well-ordered hexagonal mesostructured normal to the underlying electrode support. Mass transport through the films and especially between each layer is demonstrated by cyclic voltammetry using a redox probe in solution. In addition, such multilayered films functionalized with ferrocene groups covalently attached to the internal mesopore walls exhibit long-range electron transfer by electron hopping. The charge transfer processes can be modulated by elaborating sandwich silica-ferrocene/silica-alone/silica-ferrocene multilayers in which insulating silica-alone acts as a barrier to electron hopping. (C) 2017 Elsevier Ltd. All rights reserved.