Striped networks and other hierarchical structures in A mB mC n (2m+n)-miktoarm star terpolymer melts

Abstract

Using dissipative particle dynamics simulations we give numerical evidence of the formation of "striped" (or AB alternating) diamond and gyroid network structures and other hierarchical morphologies in AmBmCn (2m+n)-miktoarm star terpolymers where the main variable is the ratio x=n/m with m,n being the number of equal length polymer arms of A and B and C, respectively. The formed networks are purely a result of the star topology, as clearly shown by direct comparison with parallel ABC miktoarm star terpolymer simulations with matching overall composition. Progressively changing x, the system adopts the following phase sequence: three-colored lamellae, C spheres embedded in AB lamellae, C spheres decorating AB lamellae, three-colored [6.6.6] tiling, AB striped diamond network, AB striped gyroid network, AB striped hexagonally arranged cylinders, and finally AB striped globular aggregates. The striped gyroid is particularly interesting as it constitutes an inherently chiral structure made from achiral building blocks.