Low pressure plasma deposition conditions are investigated yielding oxygencontaining lateral gradient coatings (a─C:H:O) by means of an inclined static mask partly shielding the substrate. Such lateral gradient coatings are formed by the diffusion of film-forming species with different reactivities underneath the mask.Surface characterization revealed varying film growth conditions below the mask different from direct plasma exposure with increasing distance from the mask/plasma edge: i) exponentially decreasing film growth; ii) decreasing roughness following the thickness trend; iii) decreasing hydrophilicity; iv) variation in cross-linking; and v) different chemical composition.Oxygen-rich film-forming species appeared to react closer to the mask/plasma edge, while oxygen-poor film-forming species can diffuse deeper, leading to a pronounced gradient in chemical composition and in cross-linking in the masked area. K E Y W O R D Sdiffusion, film-forming species, lateral gradient structure, plasma polymerization, static mask Plasma Process Polym. 2018;15:e1700185.www.plasma-polymers.com

Front Cover: Plasma polymerization was investigated on a substrate partly shielded from direct plasma exposure by an inclined static mask protecting film growth from ion bombardment and moderating diffusion processes. A lateral gradient coating was formed underneath the mask thanks to the diffusion of film‐forming species showing different reactivities, resulting in varying chemistry and wettability as well as decreasing film thickness and roughness with increasing distance from the mask/plasma edge. Further details can be found in the article by Marianne Vandenbossche et al. (http://doi.wiley.com/10.1002/ppap.201700185).