Advanced (in situ) surface analysis of organic coating/metal oxide interactions for corrosion protection of passivated metals

Passivated metal surfaces are commonly coated by organic coatings to protect them against various types of corrosion such as pitting, intergranular, and exfoliation. Achieving durable coating protection in hostile conditions is a ubiquitous problem of interface engineering, which requires a local understanding on chemical interactions at the hybrid polymer/metal oxide interface. However, it is very challenging to get useful information directly from this solid/solid interface. This article explains different synthesis and analysis approaches that allow the (in situ) investigation of the buried interface, leading to the extraction of information regarding the molecular interfacial chemistry by surface analysis techniques. Different pretreatments of the metal oxide substrate prior to coating can improve interfacial bonding strength and durability. Therefore, it will be shown that certain surface oxide properties are directly correlated with the quality of interfacial interactions. Next, different hybrid structure synthesis approaches are discussed, which allow to characterize chemical interactions locally at the interface by conventional surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ions mass spectrometry (ToF-SIMS), and other spectroscopic techniques. A new generation of techniques such as ambient pressure XPS (APXPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) in the Kretschmann geometry, and sum-frequency generation vibrational spectroscopy are nowadays utilized to investigate the influence of external conditions on the hybrid interface such as changing ambient conditions in situ.