Vapor-phase grafting of functional silanes on atomic layer deposited Al₂O₃

Journal Article · 23 April 2023 · Journal of Vacuum Science and Technology A

DOI: https://doi.org/10.1116/6.0002364 · OSTI ID:2007754

Rozyyev, Vepa  ^[1]; Shevate, Rahul  ^[2]; Pathak, Rajesh  ^[2]; Murphy, Julia G.  ^[3]; Mane, Anil U.  ^[4]; Sibener, S. J.  ^[3]; Elam, Jeffrey W.  ^[4]

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1. Univ. of Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Advanced Materials for Energy-Water Systems (AMEWS)
2. Argonne National Laboratory (ANL), Argonne, IL (United States)
3. Energy Frontier Research Centers (EFRC) (United States). Advanced Materials for Energy-Water Systems (AMEWS); Univ. of Chicago, IL (United States)
4. Argonne National Laboratory (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Advanced Materials for Energy-Water Systems (AMEWS)

Fundamental studies are needed to advance our understanding of selective adsorption in aqueous environments and develop more effective sorbents and filters for water treatment. Vapor-phase grafting of functional silanes is an effective method to prepare well-defined surfaces to study selective adsorption. In this investigation, we perform vapor phase grafting of five different silane compounds on aluminum oxide (Al2O3) surfaces prepared by atomic layer deposition. These silane compounds have the general formula L3Si–C3H6–X where the ligand, L, controls the reactivity with the hydroxylated Al2O3 surface and the functional moiety, X, dictates the surface properties of the grafted layer. We study the grafting process using in situ Fourier transform infrared spectroscopy and ex situ x-ray photoelectron spectroscopy measurements, and we characterize the surfaces using scanning electron microscopy, atomic force microscopy, and water contact angle measurements. Here, we found that the structure and density of grafted aminosilanes are influenced by their chemical reactivity and steric constraints around the silicon atom as well as by the nature of the anchoring functional groups. Methyl substituted aminosilanes yielded more hydrophobic surfaces with a higher surface density at higher grafting temperatures. Thiol and nitrile terminated silanes were also studied and compared to the aminosilane terminated surfaces. Uniform monolayer coatings were observed for ethoxy-based silanes, but chlorosilanes exhibited nonuniform coatings as verified by atomic force microscopy measurements.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Advanced Materials for Energy-Water Systems (AMEWS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 2007754
• Journal Information: Journal of Vacuum Science and Technology A, Journal Name: Journal of Vacuum Science and Technology A Journal Issue: 3 Vol. 41; ISSN 0734-2101
• Publisher: American Vacuum Society / AIPCopyright Statement
• Country of Publication: United States
• Language: English