Omotosho Khalil D, Lyon Zachary, Shevchenko Elena V, Berman Diana
Materials Science and Engineering Department, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA.
Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, USA.
Polymers (Basel). 2023 Oct 14;15(20):4088. doi: 10.3390/polym15204088.
The conformal nanoporous inorganic coatings with accessible pores that are stable under applied thermal and mechanical stresses represent an important class of materials used in the design of sensors, optical coatings, and biomedical systems. Here, we synthesize porous AlO and ZnO coatings by the sequential infiltration synthesis (SIS) of two types of polymers that enable the design of porous conformal coatings-polymers of intrinsic microporosity (PIM) and block co-polymer (BCP) templates. Using quartz crystal microbalance (QCM), we show that alumina precursors infiltrate both polymer templates four times more efficiently than zinc oxide precursors. Using the quartz crystal microbalance (QCM) technique, we provide a comprehensive study on the room temperature accessibility to water and ethanol of pores in block copolymers (BCPs) and porous polymer templates using polystyrene-block-poly-4-vinyl pyridine (PS75-b-P4VP25) and polymers of intrinsic microporosity (PIM-1), polymer templates modified by swelling, and porous inorganic coatings such as AlO and ZnO synthesized by SIS using such templates. Importantly, we demonstrate that no structural damage occurs in inorganic nanoporous AlO and ZnO coatings synthesized via infiltration of the polymer templates during the water freezing/melting cycling tests, suggesting excellent mechanical stability of the coatings, even though the hardness of the inorganic nanoporous coating is affected by the polymer and precursor selections. We show that the hardness of the coatings is further improved by their annealing at 900 °C for 1 h, though for all the cases except ZnO obtained using the BCP template, this annealing has a negligible effect on the porosity of the material, as is confirmed by the consistency in the optical characteristics. These findings unravel new potential for the materials being used across various environment and temperature conditions.
具有可及孔隙的共形纳米多孔无机涂层在施加的热应力和机械应力下稳定，是用于传感器、光学涂层和生物医学系统设计的一类重要材料。在此，我们通过两种聚合物的顺序浸润合成（SIS）来合成多孔AlO和ZnO涂层，这两种聚合物能够设计多孔共形涂层——固有微孔聚合物（PIM）和嵌段共聚物（BCP）模板。使用石英晶体微天平（QCM），我们表明氧化铝前驱体浸润两种聚合物模板的效率比氧化锌前驱体高四倍。使用石英晶体微天平（QCM）技术，我们对嵌段共聚物（BCP）和多孔聚合物模板中孔隙在室温下对水和乙醇的可及性进行了全面研究，这些模板使用聚苯乙烯 - 嵌段 - 聚4 - 乙烯基吡啶（PS75 - b - P4VP25）和固有微孔聚合物（PIM - 1），通过溶胀改性的聚合物模板，以及使用此类模板通过SIS合成的多孔无机涂层，如AlO和ZnO。重要的是，我们证明在水冻结/融化循环测试期间，通过聚合物模板浸润合成的无机纳米多孔AlO和ZnO涂层没有发生结构损伤，这表明涂层具有出色的机械稳定性，尽管无机纳米多孔涂层的硬度受聚合物和前驱体选择的影响。我们表明，通过在900°C下退火1小时，涂层的硬度进一步提高，不过对于除使用BCP模板获得的ZnO之外的所有情况，这种退火对材料孔隙率影响可忽略不计，这由光学特性的一致性所证实。这些发现揭示了这些材料在各种环境和温度条件下使用的新潜力。
