W. H. Tsai

Molecular structure of interphases between DGEBA/BTDA adhesives and silver substrates using surface-enhanced Raman scattering

Abstract Surface-enhanced Raman scattering (SERS) was used for the non-destructive characterization of interphases between epoxy/anhydride adhesive systems and silver substrates. The normal raman spectrum of benzophenone tetracarboxylic dianhydride (BTDA) was characterized by strong bands near 1785 and 1860 cm−1 that were assigned to the anhydride groups, a strong band near 1690 cm−1 that was assigned to the benzophenone C─O stretching mode, and by a strong band near 1620 cm−1 that was attributed to vibration v(8b) of the benzene rings. The bands due to v(8b) and to the benzophenone C─O stretching mode were prominent in the SERS spectrum of BTDA but the bands related to the anhydride group were missing, indicating that the anhydride groups were hydrolyzed at the silver surface to form carboxylate groups. A band related to a CH out-of-plane bending mode which was absent from the normal Raman spectrum of BTDA was strong in the SERS spectrum, indicating that the molecules were adsorbed onto silver with a fla...