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Synthesis of Polystyrene‐ block ‐Poly(4‐vinylpyridine) Ellipsoids through Macro‐RAFT‐Agent‐Mediated Dispersion Polymerization: The Solvent Effect on the Morphology of the In Situ Synthesized Block Copolymer Nanoobjects
Author(s) -
Liu Hui,
Gao Chengqiang,
Ding Zhonglin,
Zhang Wangqing
Publication year - 2016
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201500273
Subject(s) - copolymer , polymer chemistry , materials science , polystyrene , polymerization , chain transfer , cyclohexane , raft , dispersion polymerization , solvent , chemical engineering , reversible addition−fragmentation chain transfer polymerization , radical polymerization , chemistry , polymer , organic chemistry , composite material , engineering
The solvent character affecting the morphology of the block copolymer nanoobjects prepared through the macro‐RAFT‐agent‐mediated dispersion polymerization is discussed. It is found that, in the polystyrene macro‐RAFT‐agent‐mediated dispersion polymerization of 4‐vinylpyridine in the solvent of the toluene/cyclohexane mixture, the toluene/cyclohexane weight ratio in the polymerization solvent highly affected the morphology of the in situ synthesized polystyrene‐ block ‐poly(4‐vinylpyridine) (PS‐ b ‐P4VP) nanoobjects, and nanospheres are formed in pure toluene and ellipsoids are formed in the toluene/cyclohexane mixture containing 10–20 wt% cyclohexane, respectively. The formation of the PS‐ b ‐P4VP ellipsoids is explored by checking the polymerization kinetics and the morphology of the in situ synthesized PS‐ b ‐P4VP nanoobjects at different monomer conversion. It was revealed that the formation of ellipsoids is possibly through the nanosphere–nanosphere fusion and/or the nanosphere‐to‐rod transition with the extension of the poly(4‐vinylpyridine) block during the dispersion reversible addition–fragmentation chain transfer (RAFT) polymerization. This study demonstrates that tuning the solvent character may be a promising method to tune the morphology of block copolymer nanoobjects under dispersion RAFT polymerization condition.