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Polymer Crystallization Influenced by Initial Orientation of Cylindrical Diblock Copolymers in Thin Films
Author(s) -
Yang Ping,
Han Yanchun
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.200800285
Subject(s) - perpendicular , materials science , crystallization , annealing (glass) , metastability , cylinder , cyclohexane , polystyrene , composite material , polymer , thin film , crystallography , nanotechnology , geometry , chemical engineering , chemistry , mathematics , organic chemistry , engineering
The effect of the initial states (disordered perpendicular cylinder structure vs. parallel cylinder structure) on the crystallization of polystyrene‐ block ‐poly(ethylene oxide) (PS‐ b ‐PEO) thin films during cyclohexane annealing was investigated. The cylindrical domains perpendicular or parallel to the surface were obtained by controlling the film thickness. During solvent annealing, for the film with the perpendicular cylinders, the ordering degree of cylinders was increased. The enthalpic increase is large enough for the forming of square‐shaped crystals, and subsequently the square‐shaped single crystals surrounded by the ordered hexagonally packed perpendicular cylinders evolved to the dendrite ones. For the film with the parallel cylinders, the parallel cylinders were translated to the perpendicular ones. The increased enthalpy was not large enough for the formation of square‐shaped single crystals. Instead, the dendrite‐like crystals started at the edge of terraces.