microscopy (AFM) measurements were performed with a 5500 Atomic Force
Microscope (Agilent Technologies) using an arrowshaped cantilever
(PointProbe Plus ZEISS Veritekt Microscopes - Contact Mode Low Force
Constant - Reflex Coating (PPP-ZEILR), Nanosensors, tip diameter <
10 nm). All images were recorded in the intermittent contact mode
with constant force. The experiments were performed in a glovebox
with argon flow to minimize contact to air. An area of 5 μm
× 5 μm was chosen for all measurements. For data processing,
the software MountainsSPIP (Digital Surf/Image Metrology) was utilized.
The calculation of the arithmetic mean deviation of the surface roughness
(called average surface roughness, Sa,
for simplicity) was done according to EUR 15178N. The maximal surface
roughness (Sm) is the difference between
the highest and the lowest point on the sample surface within the
region of interest.