Microdomain spacing of ABB graft copolymers and their chain conformations in bulk

Abstract Lamellar microphase-separated structures of graft copolymers of the ABB type were investigated by both small-angle X-ray (SAXS) and neutron (SANS) scattering. The samples used are two three-arm star-shaped polymers, with a polystyrene graft at the centre of a poly(2-vinylpyridine) chain, i.e. poly(2-vinylpyridine- g -styrene-h 8 ) (SPP-30) and its deuterium labelled counterpart poly (2-vinylpyridine- g -styrene-d 8 ) (DPP-30). Lamellar domain spacing of the 0.13/0.87 mixture was measured by SAXS, and evaluated to be 83 nm, which is smaller than that of styrene-2-vinylpyridine (SP) diblock copolymer with the same molecular weight and composition. This result is due to the difference in the chain architecture between the SPP graft and SP block copolymers.