Structural evolution of multilayered, crystalline-amorphous diblock copolymer thin films

The evolution of the morphology of a crystalline/amorphous diblock copolyme r poly(ethylene oxide-b-1,4 butadiene) (P(EO-b-BD)) upon crystallization in thin films was studied via interference optical microscopy. Two-dimensiona l crystallization confined within the PEO lamellar layers was observed with retention of the microphase-separated lamellar morphology formed in the me lt state. The morphology was further characterized by TEM and electron diff raction which showed it to consist of alternating layers of PEO and PBD wit h PEO crystalline chains oriented perpendicular to the lamellar layers of t he microphase-separated structure. Multiple parallel. layers of crystalline PEO were found by electron diffraction to be in orientational registry eve n though they were separated by approximately 10 nm thick layers of amorpho us PBD.