Publication Date:
2015-11-24
Description:
Pentablock copolymers PMA-PPO-PEO-PPO-PMA synthesized via atom transfer radical polymerization (ATRP) were self-assembled with varying amounts of γ-CDs to prepare poly(pseudorotaxanes) (PPRs). When the concentration of γ-CDs was lower, the central PEO segment served as a shell of the micelles and was preferentially bent to pass through the γ-CD cavity to construct double-chain-stranded tight-fit PPRs characterized by a channel-like crystal structure. With an increase in the amount of γ-CDs added, they began to accommodate the poly(methyl acrylate) (PMA) segments dissociated from the core of the micelles. When more γ-CDs were threaded and slipped over the segments, the γ-CDs were randomly distributed along the pentablock copolymer chain to generate single-chain-stranded loose-fit PPRs and showed no characteristic channel-like crystal structure. All the self-assembly processes of the pentablock copolymers resulted in the formation of hydrogels. After endcapping via in situ ATRP of 2-methacryloyloxyethyl phosphorylcholine (MPC), these single-chain-stranded loose-fit PPRs were transformed into conformational identical polyrotaxanes (PRs). The structures of the PPRs and PRs were characterized by means of 1 H NMR, GPC, 13 C CP/MAS NMR, 2D 1 H NOESY NMR, FTIR, WXRD, TGA and DSC analyses. Beilstein J. Org. Chem. 2015, 11, 2267–2277. doi:10.3762/bjoc.11.247
Keywords:
ATRPγ-CDdouble-chain-strandedpentablock copolymerpoly(pseudorotaxane)polyrotaxanesingle-chain-stranded
Electronic ISSN:
1860-5397
Topics:
Chemistry and Pharmacology
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