title: Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine.
abstract: 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.
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Kong
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Ye
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Ai-Ying
authors.initials: AY
authors.lastname: Zhang
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Zeng-Guo
authors.initials: ZG
authors.lastname: Feng
keywords: ATRP; double-chain-stranded; pentablock copolymer; poly(pseudorotaxane); polyrotaxane; single-chain-stranded; γ-CD