AFM: Topography images and phase mode images were acquired in the air in tapping mode at a scan rate of 3 Hz and a resolution of 512×512 pixels 2 on an MFP3D INFINITY microscope (Oxford Instrument, UK). Semi-contact silicon AC160TS AFM tips (Olympus, Japan) with a cantilever spring constant of 26 N m -1 were used. Surface topography was acquired by maintaining a constant first resonance amplitude in the cantilever via the feedback loop of the AFM acting on the piezo Z direction. The phase shift signal was recorded at the same time. Prior to the analysis, the APCN films were cross-sectioned and surfaced at 0°C using a UC6 Cryo-Ultramicrotome (Leica, Germany) to get a representative image of the inner film composition and avoid possible skin effects. Data analysis was performed with MountainSpip software (Digital Surf, France).