Domain sizes determination for styrene-isobutylene block copolymer systemsusing solid-state NMR spectroscopy

Solid-state NMR techniques were used to evaluate the sizes of the dispersed domains and the interface between the minor and the major phase in heterog eneous block copolymer systems with a relatively poor degree of ordering. P roton spin-lattice relaxation measurements and spin diffusion experiments w ere carried out on five samples of linear and star block copolymers of styr ene, styrene-co-indene, and isobutylene. The morphology of the dispersed ph ase was considered cylindrical for all samples. The diameters of the disper sed cylinders were found to range between 7.9 and 48.5 nm for the linear sa mples and 22.6 nm for the star block copolymer sample. The thickness of the interface was estimated to be between 1.0 and 1.3 nm for all samples. SAXS measurements were employed to confirm the validity of the NMR data analysi s.