The impact of silane on the hygrothermal stability of epoxy coatings was investigated by specular neutron reflectivity (NR). By comparing the hygrothermal degradation behavior of neat novolac epoxy coating and corresponding bis[3-(triethoxysilyl)propyl]tetrasulfide-laced epoxy coating, the role of silane was elucidated. Accelerated aging was achieved by exposing the samples to 80 degrees C liquid water. For the pure epoxy coating, degradation occurs at the coating-substrate interface, which makes the coating vulnerable to adhesion failure. For epoxy-silane coating the addition of silane imparts resistance to the interfacial degradation observed in the neat epoxy coating. (C) Koninklijke Brill NV, Leiden, 2010