Film formationFilm formation has mainly been studied in films cast from waterborne paints/coatings. We have to a lesser degree studied solventborne paints/coatings and powder coatings.
After evaporation of the continuous phase the film formation behave in a similar way independent if the coating was cast from water or solvent. Furthermore, 100 % paints such as UV-liquids and powder coatings also form films in a similar way as other low-molecular weight polymers (cast from solvent or water). In most paint systems diffuse oligomers/monomers and hardeners to even out the film and finally the film cross-links/ polymerises after application at the surface.
In waterborne latex paint systems the latex is polymerised in solution and consequently prior to casting the film on the substrate. A strong film is obtained by diffusion of polymer molecules over particle boundaries.
AFM phase images of surfactant migration
in latex/binder films with and without thickener
(sulfur content from ESCA analysis)
Under the film formation tend small molecules to migrate to various interfaces where these molecules affect properties such as adhesion, blocking, re-coatability, gloss, haze, dirt removal etc.