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

Lamellar microphase-separated structures of graft copolymers of the ABB typ e were investigated by both small-angle X-ray (SAXS) and neutron (SANS) sca ttering. The samples used are two three-arm star-shaped polymers, with a po lystyrene 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 counterp art 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 copolyme r 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 co polymers. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.