Direct observation of domain wall excitations in symmetric diblock copolymer melts at and above the order-disorder transition

The dynamics of the chain junctions in a lamellar diblock copolymer melt around the order-disorder transition temperature (ODT) has been investigated by neutron spin echo (NSE) spectroscopy, utilizing deuterated diblock copolymers with a hydrogen-labeled section at the junction point. We observed a dynamic response which was more than one order of magnitude faster than expected from standard Rouse dynamics. The corresponding driving force was shown to relate to interfacial tension implying the existence of interfacial walls near the ODT.