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Strain‐Induced Phase Morphology in Melt Drawn Ultrathin Highly Oriented Block Copolymer Films
Author(s) -
Keller Thomas,
Semmler Christian,
Jandt Klaus D.
Publication year - 2008
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200800060
Subject(s) - copolymer , materials science , morphology (biology) , polystyrene , annealing (glass) , polymer , polymer chemistry , composite material , genetics , biology
A strain‐induced microphase morphology has been established by the melt drawing process in a high molecular weight asymmetric polystyrene‐ block ‐poly(vinyl‐2‐pyridine) (PS‐ b ‐P2VP) diblock copolymer. For the first time to the best knowledge of the authors, the melt drawing process has been applied to block copolymers to produce free‐standing, ultrathin block copolymer films with a thickness of ≈100 nm. Intriguingly, during the melt drawing of the polymer a global strain‐induced unidirectional order of the microphase separated needle‐like domains of the block copolymer was generated. This morphology consists of a PS matrix with embedded highly oriented P2VP needle‐like domains oriented parallel to the drawing direction. The needle‐like morphology is explained by a simplified extended chain model of the diblock copolymer chains. Annealing of the films leads to a transition from the strain‐induced needle‐like morphology toward the quasi‐equilibrium sphere‐like morphology.