Oriented primary crystal nucleation in lamellar diblock copolymer system

We report a numerical study of the primary crystal nucleation of diblock copolymers in a lamellar phase. Only one of two polymer blocks is crystallizable; the other is maintained in a glassy state. We find that crystals in this lamellar geometry tend to nucleate with the chain axis perpendicular to the lamellar plane. However, if in the same lamellar structure, we break the junction between the crystallizable and non-crystallizable blocks of the polymers, we find that crystallites tend to align parallel to the lamellar plane. This observation clarifies the molecular origin of the competition between parallel and perpendicular crystallite orientations in real block-copolymer systems.

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