title: Hydrolytic Stability of 3-Aminopropylsilane Coupling Agent on Silica and Silicate Surfaces at Elevated Temperatures.
abstract: 3-Aminopropylsilane (APS) coupling agent is widely used in industrial, biomaterial, and medical applications to improve adhesion of polymers to inorganic materials. However, during exposure to elevated humidity and temperature, the deposited APS layers can decompose, leading to reduction in coupling efficiency, thus decreasing the product quality and the mechanical strength of the polymer-inorganic material interface. Therefore, a better understanding of the chemical state and stability of APS on inorganic surfaces is needed. In this work, we investigated APS adhesion on silica wafers and compared its properties with those on complex silicate surfaces such as those used by industry (mineral fibers and fiber melt wafers). The APS was deposited from aqueous and organic (toluene) solutions and studied with surface sensitive techniques, including X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), streaming potential, contact angle, and spectroscopic ellipsometry. APS configuration on a model silica surface at a range of coverages was simulated using density functional theory (DFT). We also studied the stability of adsorbed APS during aging at high humidity and elevated temperature. Our results demonstrated that APS layer formation depends on the choice of solvent and substrate used for deposition. On silica surfaces in toluene, APS formed unstable multilayers, while from aqueous solutions, thinner and more stable APS layers were produced. The chemical composition and substrate roughness influence the amount of deposited APS. More APS was deposited and its layers were more stable on fiber melt than on silica wafers. The changes in the amount of adsorbed APS can be successfully monitored by streaming potential. These results will aid in improving industrial- and laboratory-scale APS deposition methods and increasing adhesion and stability, thus increasing the quality and effectiveness of materials where APS is used as a coupling agent.
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Denis V
authors.identifier: http://orcid.org/0000-0001-7279-1292
authors.initials: DV
authors.lastname: Okhrimenko
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Akin
authors.initials: A
authors.lastname: Budi
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Marcel
authors.identifier: http://orcid.org/0000-0002-6653-836X
authors.initials: M
authors.lastname: Ceccato
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.|Department of Biomedical Sciences and Biofilm Research Center for Biointerfaces, Health & Society, Malmoe University , Malmoe 20500, Sweden.
authors.forename: Marité
authors.identifier: http://orcid.org/0000-0003-0392-3540
authors.initials: M
authors.lastname: Cárdenas
authors.affiliation: ROCKWOOL International A/S , Hovedgaden 584, 2640 Hedehusene, Denmark.
authors.forename: Dorte B
authors.initials: DB
authors.lastname: Johansson
authors.affiliation: ROCKWOOL International A/S , Hovedgaden 584, 2640 Hedehusene, Denmark.
authors.forename: Dorthe
authors.initials: D
authors.lastname: Lybye
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bechgaard
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Martin P
authors.identifier: http://orcid.org/0000-0002-4921-1461
authors.initials: MP
authors.lastname: Andersson
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen , 2100 Copenhagen OE, Denmark.
authors.forename: Susan L S
authors.initials: SL
authors.lastname: Stipp
keywords: adhesion; aminosilane; coatings; fibers; material stability; mineral wool; surface treatment