Materials Science and Engineering Department and Advanced Materials and Manufacturing Processes Institute, University of North Texas, 1155 Union Circle, Denton, TX 76203, United States of America.
Nanotechnology. 2018 Dec 7;29(49):495703. doi: 10.1088/1361-6528/aae144. Epub 2018 Sep 13.
Inorganic nanoporous materials with highly accessible pores are of great interest for the design of efficient catalytic, purification and detection systems. Limited access to the pores is a common problem associated with traditional approaches for the synthesis of porous materials, affecting the functionality of the low-density structure. Recently, infiltration of a nanoporous polymer template with inorganic precursors followed by oxidative annealing was proposed as a new and efficient approach to creating porous inorganic structures with controlled thickness, composition and pore sizes. Here, we report an ultra-high accessibility of the pores in porous films prepared via polymer-swelling-assisted sequential infiltration synthesis (SIS). Using a quartz crystal microbalance technique, we show the increased solvent adsorbing capabilities of highly porous alumina films as a result of high interconnectivity of the pores in such structures. The directionality and highly interconnected nature of the pores are demonstrated in experiments with the partial blocking of pore access by the deposition of a single-layer graphene that is not transparent to solvent. 60% of the pores remain accessible when only 20% of the surface is exposed to solvent. Using humidity detection as an example, we also show that highly porous alumina produced by polymer-swelling-assisted SIS is a promising candidate for sensing applications.
具有高可及性孔的无机纳米多孔材料对于设计高效的催化、净化和检测系统具有重要意义。孔的可及性有限是与传统多孔材料合成方法相关的一个常见问题，这会影响低密度结构的功能。最近，提出了一种新的有效方法，即使用无机前体对纳米多孔聚合物模板进行渗透，然后进行氧化退火，从而可以制备具有可控厚度、组成和孔径的多孔无机结构。在这里，我们报告了通过聚合物溶胀辅助顺序渗透合成（SIS）制备的多孔薄膜中孔的超高可及性。使用石英晶体微天平技术，我们展示了高度多孔氧化铝薄膜由于在这种结构中孔的高连通性而具有增强的溶剂吸附能力。通过在仅 20%的表面暴露于溶剂的情况下沉积单层石墨烯来部分阻塞孔的可及性，证明了孔的方向性和高度连通性。通过湿度检测作为示例，我们还表明，通过聚合物溶胀辅助 SIS 制备的高度多孔氧化铝是传感应用的有前途的候选材料。
