Figure 3.

(a) Schematic illustrating the relationship between spray distance, the amount of dispersion reaching the substrate, and the resulting film state of spray-coated nanoparticles. (b,c) Optical images of the surface of CuNPs/PMMA substrates sprayed at different spray distances: (b) 5 cm (short distance) and (c) 20 cm (long distance) from the substrate. The dispersion solvent is DCM. The high-resolution image on the right in (b) shows agglomerated CuNPs after drying. (c) Coating stability of the CuNPs/PMMA substrate sprayed at a distance of 20 cm from the substrate. The image on the right in (c) shows the particles peeling off when wiped with a cotton swab, indicating that the CuNPs are not properly immobilized on the substrate.