ORIENTATIONAL DIFFUSION OF HOMOPOLYMER CHAINS IN A LAMELLAR STRUCTUREOF DIBLOCK COPOLYMER - A DEUTERIUM NMR-STUDY

Chain dynamics in lamellar microdomains of polystyrene-polybutadiene ( PS-PB) diblock copolymer is investigated by deuterium nuclear magnetic resonance (n.m.r.). The experiments are performed on perdeuterated PB homopolymer chains dissolved in the PB sublayers of a macroscopically oriented PS-PB sample. The n.m.r, spectra show that homopolymer chain segments undergo uniaxial reorientations around the direction normal to the layers. This local uniaxial order implies that the PB chains of the diblock are slightly elongated and that the segments between chai ns are correlated in orientation.