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In Situ Nanoscale Characterization of Water Penetration through Plasma Polymerized Coatings



Yang Zhou, Brian Patrick Josey, Emmanuel Anim-Danso, Brian B. Maranville, Jenia Karapetrova, Zhang Jiang, Qixin Zhou, Ali Dhinojwala, Mark D. Foster


The search continues for means of making quick determinations of the efficacy of a coating for protecting a metal surface against corrosion. One means of reducing the time scale needed to differentiate the performance of different coatings is to draw from nanoscale measurements inferences about macroscopic behavior. Here we connect observations of the penetration of water into plasma coating and substrate to the macroscopically observable corrosion for those systems. A comparatively hydrophobic coating made by plasma polymerization of the monomer hexamethyldisiloxane (HMDSO) is less readily penetrated and provides better protection than a comparatively hydrophilic coating made from maleic anhydride (MA). Measurements with off-specular X-ray scattering and neutron reflectivity (NR) show that water not only moves more readily through the hydrophilic film, but that once reaching the interface the water dramatically disrupts the coating/substrate interface morphology in a manner obvious in raw off-specular scattering data. Measurements with infrared-visible sum frequency generation spectroscopy (SFG), which probes the chemical nature of the interface, make clear that the morphological coating and metal. With this disruption, macroscopic corrosion occurs much more rapidly. An Al panted coated with pp-MA corrodes after one day in salt spray, while a similarly thin (30 nm) pp-HMDSO coating protects an Al panel for a period on the order of one month.


neutron reflectometry, plasma polymerized coating, corrosion, interface, diffusion


Zhou, Y. , Josey, B. , Anim-Danso, E. , Maranville, B. , Karapetrova, J. , Jiang, Z. , Zhou, Q. , Dhinojwala, A. and Foster, M. (2018), In Situ Nanoscale Characterization of Water Penetration through Plasma Polymerized Coatings, Langmuir, [online], (Accessed June 23, 2024)


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Created July 31, 2018, Updated October 12, 2021