Swelling Behavior of Blended Multilayer Thin Films Using Neutron Reflectivity.

Surface structure and swelling behavior of polyelectrolyte multilayer films of poly (allylamine hydrochloride) (PAH)/poly(sodium 4-styrenesulfonate) (PSS):poly(methacrylic acid) (PMAA) have been studied using X-ray and neutron reflectivity (NR). Samples have been prepared either using spin-assisted self assembly or dip coating. Swelling measurements were done in a chamber by using saturated salt solutions. PSS:PMAA blend composition was varied from pure PSS to pure PMAA to investigate the effect of strong polyelectrolyte on the swelling of the multilayer film. Multilayer films prepared by spin assisted deposition yields well defined films with much smooth interfaces than the films prepared by dip coating. NR results showed that incorporation of strong polyelectrolyte, PSS, into the multilayer decreases the swelling capacity of the film.