화학공학소재연구정보센터
Journal of Adhesion, Vol.82, No.12, 1117-1132, 2006
Novel self-assembling silane for abhesive and adhesive applications
The potential benefits from using a novel vinyl-terminated long alkyl-chain self-assembling silane (VTS) have been investigated. A relatively high water contact angle of 83 degrees was found for water on the VTS-pretreated soda-lime glass surface. This revealed that the degree of hydrophobicity of this surface was far more pronounced than for the ultrasonically-cleaned glass surface or the gamma-glycidoxypropyl-trimethoxy silane (GPS) - pretreated glass surface, which gave contact angles of 14 degrees and 42 degrees, respectively. Further, good agreement between the measured and the theoretical contact angles for a fully adsorbed vinyl-terminated self-assembled monolayer surface implied that the VTS molecules were adsorbed with the vinyl-terminal groups orientated away from the glass surface. Indeed, X-ray photoelectron spectroscopy (XPS) analysis confirmed that the VTS molecules were adsorbed as a monolayer with the vinyl-terminal groups orientated away from the glass surface. Double-cantilever beam joints were prepared using these various pretreated-glass substrates, using an epoxy adhesive, and they were tested employing a fracture-mechanics approach. The adhesive fracture energy, GC, of the VTS-pretreated glass/epoxy joints was found to be far lower in value than for the ultrasonically cleaned joints or the GPS-pretreated joints. The potential applications of this novel long alkyl-chain silane are twofold: ( a) the relatively very poor adhesion of the VTS pretreatment enables this silane to be used as an excellent adhesive layer, i.e., as a release agent, and (b) the presence of reactive vinyl-terminal groups might allow this silane to be activated to form functional groups that may then react with an adhesive, such as an epoxy resin, and so act as an excellent adhesion promoter to increase the durability of the adhesive joint.