Core-shell gyroid morphology in a poly(isoprene-block-styrene-block-dimethylsiloxane) triblock copolymer

We report a new morphology in a poly(isoprene-block-styrene-block-dimethyls iloxane ABC triblock copolymer. The most probable symmetry of the morpholog y (Ia3d) was determined from two-dimensional SAXS measurements performed on a sample with long-range order induced by an oscillatory shear field. By c omparing the predictions of self-consistent field theory with TEM and SAXS and SANS powder diffraction patterns, we deduced that the morphology is a c ore-shell gyroid comprised of two independent and triply periodic poly(dime thylsiloxane) networks encased in poly(styrene) shells and separated by a c ontinuous poly(isoprene) domain. Thus, this unique nanostructure divides sp ace into five independent, three-dimensionally continuous domains.