title: Why does silane enhance the protective properties of epoxy films?
abstract: Using neutron reflectivity, the protection mechanisms of a novel one-step epoxy-silane coating system were investigated in terms of coating structure and water response behavior. By comparing pure epoxy and epoxy-silane mixtures in various aqueous environments, the effects of the addition of silane were determined. Specifically, a bridged bis-silane coupling agent with six alkoxy moieties and a polysulfur bridge was investigated. The key mechanisms of silane-enhanced protection are (1) the silane is enriched at the substrate-coating interface, forming a hydrophobic dense interfacial layer and good adhesion to the substrate, and (2) the silane serves as a cross-linker, resulting in a denser and less hydrophilic bulk film compared to the neat epoxy. The hydrophobic nature of bis-sulfur silane also increases the overall hydrophobicity of the mixed film.
authors.affiliation: Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0012, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Dale W
authors.initials: DW
authors.lastname: Schaefer
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D004852:Epoxy Compounds / Q000737:chemistry*; D008567:Membranes, Artificial; D015394:Molecular Structure; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; D008567:Membranes, Artificial; D012821:Silanes; D014867:Water