RMS roughness (RRMS) of the patterned dextranized regions (DEX-PU, DEX-PS and DEX-PU with LiCl) and oxidized regions (OX-PU, OX-PS and OX-PU with LiCl) in air and PBS measured by AFM (80×80 μm2). For the dextranized regions, the RRMS in air is lowest for DEX-PU with LiCl substrates, slightly larger for DEX-PS substrates and highest for DEX-PU substrates, whereas in PBS, RRMS remains unaltered for DEX-PU with LiCl, decreases for DEX-PU but increases for DEX-PS substrates. This behavior can be explained in terms of hydrogen bonding, which is inhibited by adding LiCl. On the other hand, the oxidized regions show very similar RRMS in air, independent of the substrate. Here the RRMS increases in PBS for the OX-PU and OX-PS substrates due to the swelling of residual dextran molecules, but remains unaltered for OX-PU with LiCl substrates.