In some samples, we observed specific patterns of 3D aggregates that corresponded to salt residues in the other samples. They presented dendrimer-like morphology (Figure ) or radial morphology. Those specific morphologies appeared locally; therefore, we consider that they originated from the drying of the films transferred onto silicon wafers. The next observation was that the spacing between PSiFe particles changed upon adding salt. We analyzed the distances between the edges of neighboring nanoparticles. We measured distances between edges because the polydispersity of particle sizes and small batch-to-batch deviations in particles` radius obscured the effect when centers of masses were analyzed. In cases of films transferred from the pure water, the observed values corresponded well to the sizes of PNIPAM ligands in the "open" (LT) and "closed" (HT) states. When the subphase was 0.01 M KCl, the measured distances at LT were around twice as large (Figure ). At HT, it was even more visible that there were more particles further away in KCl than in the case of the water subphase. We compare the results at 0.01 M KCl, as our attempts to transfer films at 0.1 M KCl resulted in highly agglomerated, multilayered films. This contradicted the observed large shift of compression isotherms compared to lower concentrations of KCl. Usually, aggregation should manifest as the opposite effect, i.e., the change of the isotherms towards smaller values of surface area. We hypothesized that this was due to the effect described by Winkler et al., who showed ionic strength-controlled deposition of charged nanoparticles on a solid substrate. The particles were unstable at salt concentrations above 0.5 M (and below 1.75 M). However, this was the most likely explanation for the surface phenomena and different particles (much larger).