AFM measurements were conducted on a NT-MDT Integra system in tapping mode. Commercially available cantilevers (NSC35, Anfatec instruments AG) were used to investigate the morphology of aggregates. Polymer films were spin-coated at 2000 rpm on piranha cleaned silicon substrate at room temperature. Images were acquired at a scan speed of 1.5 Hz and images were analyzed with the Gwyddion software package.