Microphase separation of diblock copolymers consisting of polystyrene and acid-functionalized poly(propylene imine) dendrimers

Diblock copolymers consisting of polystyrene and acid-functionalized poly(p ropylene imine) dendrimers have been found to self-assemble spontaneously i nto regular microdomains. The hybride dendrimer-linear chain block copolyme rs yield highly asymmetric molecules which display an aggregation behavior at the strong segregation limit that differs from the well-known all-linear block copolymers. The morphological features are used to determine the rel ationship between the architecture of the blocks and the arrangement of the molecules in the bulk. Microlattice formation of these materials was exami ned by using small-angle X-ray scattering and transmission electron microsc opy techniques. By increasing the dendrimer generation, the structures chan ged from hexagonally packed cylinders with polystyrene as matrix to lamella r phases of different packing density. Good agreement between TEM and SAXS results was obtained, and the microlattice morphology was found to be highl y dependent on the dendrimer generation.