Polymer infiltration synthesis of inorganic nanoporous coatings: Does polymer template affect their properties?

• Published in: Surface & coatings technology 2023-01, Vol.452, p.129107, Article 129107
• Main Authors: Omotosho, Khalil, Tran, John, Shevchenko, Elena V., Berman, Diana
• Format: Article
• Language: English
• Subjects: Nanoporous coatings; Polymer infiltration synthesis; Sensing; Zinc oxide
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2022.129107

Synthesis of all-inorganic metal oxide architectures using polymer templates offers control over their thickness, porosity, and composition. Here, we provide insights into the synthesis of nanoporous zinc oxide films as a model system via infiltration of polymers that have different mechanisms of interaction with metal oxide precursors such as a polymer of intrinsic microporosity (PIM-1) and representative of the block-copolymers family (polystyrene-polyvinyl pyridine block copolymer). We investigated polymer infiltration process with both gas (diethyl zinc, DEZ, and water vapors) and solution (zinc acetylacetonate, Zn(acac)2, dissolved in ethanol) phase precursors. Using quartz crystal microbalance (QCM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses, we systematically studied the effect of polymer template and the form of the metal oxide precursors on the properties of synthesized metal oxide thin coatings. We demonstrate that the infiltration of polymer templates can be efficiently achieved using both gas phase and solution phase precursors. We show that the crystallinity of the synthesized 200 nm ZnO films is mainly affected by the state of the precursor (gas or solution phase) and does not depend on the polymer template type. In turn, the polymer type affects the surface termination of ZnO films. We demonstrate that the surface of porous ZnO coatings synthesized with BCP (here PS-P4VP) is more accessible than the surface of ZnO synthesized with PIM; however, despite the lower surface accessibility for ethanol molecules, ZnO synthesized via infiltration of PIM-1 with solution-phase precursors demonstrates the largest change in resistivity upon its exposure to ethanol vapor at room temperature. [Display omitted] •Polymer templates PIM-1 and PS75-b-P4VP25 are compared for synthesis of nanoporous zinc oxide films.•Infiltration of the polymer templates with zinc oxide is performed from the solution phase and gas phase.•The effect of the polymer templates on the structure and morphology of the porous zinc oxide coating is investigated.•Crystallinity of the coatings is independent of the polymer template type, while the morphology is dependent on the polymer template.•Structure and composition of the resulting zinc oxide films affect their surface accessibility and sensitivity to ethanol vapors.