A comparison of the interfacial bonding properties of carboxylic acid functional groups on zinc and iron substrates

The present work investigates the molecular interfacial bonds between carboxylic functional groups and zinc and iron substrates. Succinic acid models the functionality of many commonly used adhesives and organic coatings. On the other hand, iron and zinc form the major surface composition of galvanized steel. Consequently, studying the interfacial properties of the polymer functional groups and zinc or iron substrates illuminates the correlation of the polymer bonding characteristics and surface chemical properties of galvanized steel. In this work, X-ray photoelectron spectroscopy (XPS) and fourier transform infrared reflection absorption spectroscopy (FTIR-RAS) are combined to evaluate the surface compositions, the amount of adsorbed molecules and the interaction mechanism between the succinic acid functionalities and the differently pretreated surfaces. The results show that variation of the treatments prior to succinic molecule adsorption results in different adsorption properties, which are related to the changes in chemistry and composition of the oxide layer.