Effect of the Micelle Opening in Self-assembled Amphiphilic Block Co-polymer Films on the Infiltration of Inorganic Precursors

Journal Article · Mon Jan 07 00:00:00 EST 2019 · Langmuir

DOI:https://doi.org/10.1021/acs.langmuir.8b04039· OSTI ID:1501876

She, Yunlong ^[1]; Lee, Jihyung ^[1]; Lee, Byeongdu ; Diroll, Benjamin ; Scharf, Thomas ^[1]; Shevchenko, Elena V. ; Berman, Diana  ^[1]

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1. Materials Science and Engineering Department and Advanced Materials and Manufacturing Processes Institute, University of North Texas, 1155 Union Circle, Denton, Texas 76203, United States

Infiltration of the polymer templates with inorganic precursors using the selective vapor-phase infiltration approach, or sequential infiltration synthesis (SIS), allows the design of materials with advanced properties. Swelling of the block co-polymer (BCP) templates enables the additional control of the structure, porosity, and thickness of the composite or inorganic materials. Here, we use the highly precise quartz crystal microbalance (QCM) technique to investigate quantitatively the effect of the micelle opening by swelling and inorganic precursor infiltrating on the evolution of porosity in amphiphilic BCPs. We show that swelling of the polystyrene-block-poly-4-vinyl pyridine (PS-b-P4VP) BCP in ethanol at 75 °C occurs rapidly and results in a stable polymer structure in 30 min. By using an alumina model system, we found that swelling enables access to all available polar domains of the PS-b-P4VP film leading to an increase in the SIS-infiltrated alumina mass as compared to the nonswelled BCP layer. Our results demonstrate that swelling of the 110 nm thick BCP template results in the formation of 192 nm thick alumina films with 2 times larger alumina mass and 4 times larger effective pore volume than in case of the nonswelled sample. In the case of the thicker polymer template, the difference due to swelling becomes even more substantial because the fraction of accessible polymer is increased much more than in thin films. Our findings provide important insights into the mechanism of the infiltration of the inorganic precursors into swelled and nonswelled, spin-coated BCP templates enabling the design of highly porous thick ceramic films by SIS.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); Argonne National Laboratory - Center for Nanoscale Materials
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1501876
• Journal Information: Langmuir, Vol. 35, Issue 3; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English