Alvarez-Fernandez Alberto, Fornerod Maximiliano Jara, Reid Barry, Guldin Stefan
Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
Langmuir. 2022 Mar 15;38(10):3297-3304. doi: 10.1021/acs.langmuir.2c00074. Epub 2022 Mar 2.
Mesoporous inorganic thin films are promising materials architectures for a variety of high-value applications, ranging from optical coatings and purification membranes to sensing and energy storage devices. Having precise control over the structural parameters of the porous network is crucial for broadening their applicability. To this end, the use of block copolymers (BCP) as sacrificial structure-directing agents via micelle coassembly is a particularly attractive route, since the resultant pore size is directly related to scaling laws for the radius of gyration of the pore-forming macromolecule. However, tailoring the molecular weight of the BCP via bespoke synthesis is an elaborate process that requires precise control over highly sensitive reactions conditions. Alternative methods have emerged, based on supramolecular assembly or the addition of different swelling agents. Nevertheleses, to date, these present a negative impact on the structural order and pore size dispersity of the final inorganic mesoporous films. In this work, we propose a novel and effective method for control over pore size, porosity, and structural order, which relies on a synergistic combination of BCP selective swelling via solvent vapor annealing (SVA) and locking of the structure by condensation of the inorganic sol-gel precursors. The results obtained in this work for TiO establish SVA as a new, straightforward, simple, and powerful route for the fabrication of mesoporous thin-film materials with controllable structural characteristics.
介孔无机薄膜是用于各种高价值应用的有前途的材料结构，从光学涂层、净化膜到传感和能量存储设备。对多孔网络的结构参数进行精确控制对于扩大其适用性至关重要。为此，通过胶束共组装使用嵌段共聚物（BCP）作为牺牲结构导向剂是一条特别有吸引力的途径，因为所得孔径与成孔大分子的回转半径的标度定律直接相关。然而，通过定制合成来调整BCP的分子量是一个复杂的过程，需要对高度敏感的反应条件进行精确控制。基于超分子组装或添加不同溶胀剂的替代方法已经出现。然而，迄今为止，这些方法对最终无机介孔薄膜的结构有序性和孔径分散性产生负面影响。在这项工作中，我们提出了一种控制孔径、孔隙率和结构有序性的新颖有效方法，该方法依赖于通过溶剂蒸汽退火（SVA）对BCP进行选择性溶胀与通过无机溶胶 - 凝胶前驱体的缩合来锁定结构的协同组合。在这项工作中针对TiO获得的结果确立了SVA作为一种用于制备具有可控结构特征的介孔薄膜材料的新的、直接的、简单且强大的途径。
