Adhesion and interfacial healing between supramolecular hybrid networks and glass substrates

Adhesion towards glass and interfacial healing of partially supramolecular hybrid polymer networks featuring a range of H-bdnds content were investigated through two dedicated adhesion test methods. In a first series of tests, adhesion strength was measured by separating two substrates containing a cured inner resin layer, and shown to decrease with increasing H-bonds content in the polymer network (from 0 to 50%) as the mechanical strength of the polymer also decreased while the failure mechanism shifted from adhesive to cohesive due to the possibility to form hydrogen bonds with glass substrates. In a second step, the test was used to evaluate interface restoration through healing of the polymer matrices and results showed an increased from none to a tensile strength recovery up to 70% after 1 h healing time for the 50% H-bond polymer. Then, self-adhesion of freshly cut polymer surfaces to glass substrates was investigated, showing increasing tack with increasing H-bonds content. The influence of glass surface treatments on adhesion and interfacial recovery properties was also explored: while aminosilanes did not influence the interfacial behavior of partially supramolecular self healing polymers towards glass, trimethoxy (octadecyl)silane (ODS) modification strongly hindered their adhesion abilities, further highlighting the fundamental role of hydrogen bonds interaction with the substrates.