It is well known that water plays an important role in the degradation of adhesive strength between a wide variety of materials. It is also well established that silane coupling agents can provide excellent bond durability in aqueous environments. However, the detrimental effects of interfacial water are not limited to adhesive failure. The present study was motivated by concerns in the printed circuit board industry regarding the loss of electrical resistance, as well as adhesive failure, which may arise from water at epoxy/silane/E-glass interphases. The commercial silane finish used in this study provides excellent adhesive strength between epoxy and E-glass, and remarkable bond durability even after extensive conditioning in boiling water or a pressure cooker. However, circuit boards with this finish do not perform well in insulation resistance testing following such conditioning. The goal of this work is to develop a detailed understanding of the mechanism by which water interacts with a resin/silane interphase, with a focus on the consequences for both electrical resistance and adhesion. The present report focuses on the measurement of profiles of adsorbed moisture by neutron reflection
