The Mechanism of Adhesion Improvement of Elastomeric Silicone Sealants to Difficult-to-Bond Polymeric Substrates through Reactive or Interpenetrating Molecular Brushes

High-quality and durable adhesion of elastomeric adhesives to metallic, ceramic, and organic substrates is essential to a broad range of industries, e.g., building and construction, automotive, electronic, aerospace, biomedical, and others. The principles of engineering substrate surfaces through grafted connector molecules are discussed in this paper. In particular, two important modes of interaction for surface-grafted “molecular brushes” are investigated and experimentally verified. It is demonstrated that the inclusion of silicone- and/or amine-terminated graft molecules, such as silanes or polyethyleneimines, at polymer interfaces, results in the formation of strong molecular bridges between a range of organic substrates and elastomeric sealants leading to significantly improved bonding. The technology has been successfully adopted by global automotive industry for improving adhesion of a variety of adhesives and coatings to polyolefinic substrates.