Coalescence of crystalline microdomains driven by postannealing in a block copolymer blend

The coalescence of crystalline microdomains driven by annealing a PEO-b-PB/PB blend at temperatures near the onsets of melting of the as-crystallized samples was reported. Two or three crystalline domains were found to merge into highly elongated prolate or a rodlike domain through the postannealing. Since nearly all microdomains remained semicrystalline during the treatment, this coalescence process was distinguished from that found in the crystallization process or that associated with the order-order transition from spherical-to-cylindrical domains in block copolymer melt.