DIFFUSION IN MICROSTRUCTURED BLOCK-COPOLYMERS - CHAIN LOCALIZATION AND ENTANGLEMENTS

The diffusion (D(s)) of entangled and unentangled symmetric block copo lymers is compared, above and below the ordering transition. The lamel lar samples were not macroscopically oriented, and thus D(s) reflects a combination of mobilities parallel and perpendicular to the lamellar planes. For unentangled (Rouse) chains, D(s) is unaffected by the mic rostructure, whereas entangled (reptating) chains are retarded signifi cantly; this difference reflects an interesting combination of thermod ynamic and entanglement constraints. Furthermore, this retardation per sists into the nominally disordered state.