Effect of Molecular Weight and Arm Number on the Growth and pH-Dependent Morphology of Star Poly[2-(dimethylamino)ethyl methacrylate]/Poly(styrenesulfonate) Multilayer Films

The influence of molecular weight and arm number of star polymers on the buildup and pH-dependent morphology changes of multilayer films assembled from star poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA) and linear poly(styrenesulfonate) (PSS) was systematically investigated. Well-defined star PDMAEMA, consisting of g-cyclodextrin (CD) core and different arm number (21, 14, and 7) were successfully synthesized via atom transfer radical polymerization (ATRP). It is found that star polymers with certain arm number deposit more mass with the increase of molecular weight. As for the star polymers with almost the same arm length but different arm number, film assembled from 14-arm star PDMAEMA exhibits the fastest growth and the most significant morphology changes upon the pH 2.75 treatment. It is assumed that the interdiffusion of PSS controlled by star PDMAEMA with different structures should be responsible for the different buildup and pH-dependent morphology changes of the multilayer films.