An H-shaped polymer bonding beta-cyclodextrin at branch points: Synthesis and influences of attached beta-cyclodextrins on physical properties

作者：Mu, Cheng-Guang; Fan, Xiao-Dong^*; Tian, Wei; Bai, Yang; Yang, Zhen; Yao, Hao; Chen, Heng

来源：Journal of Polymer Science Part A: Polymer Chemistry , 2013, 51(6): 1405-1416.

DOI：10.1002/pola.26512

• cyclodextrin
• N-isopropylacrylamide
• micelles
• nonlinear polymers
• self-assembly
• synthesis

We report on the synthesis of an H-shaped polymer bonding -cyclodextrin (-CD) at branch points and influences of attached -CD on physical properties. First, a poly(ethylene glycol)(PEG)-based functional macroinitiator bearing two azidos and four chlorines at chain-ends (PEG-2N3(-4Cl)) was prepared via terminal modification reactions. Then, PEG-2N3(-4Cl) was applied to initiate the atom transfer radical polymerization of N-isopropylacrylamide, leading to the synthesis of an H-shaped block polymer with PEG as the central chain and poly(N-isopropylacrylamide) (PNIPAM) as side-arms (PEG-2N3(-4PNIPAM)). Azido groups were at the branch points of the polymer. Finally, the click reaction between PEG-2N3(-4PNIPAM) and alkynyl monosubstituted -cyclodextrin (-CD) afforded another H-shaped polymer with two -CDs bonding at the polymer branch points (PEG-2CD(-4PNIPAM)). The glass transition temperature (Tg) and lower critical solution temperature (LCST) of the H-shaped polymer increased after the attachment of -CD. The self-assembly and thermal responsive behaviors, as well as the encapsulation behaviors of PEG-2CD(-4PNIPAM) were also altered. When temperature was below the LCSTs, PEG-2N3(-2PNIPAM) dissolved in water molecularly, whereas PEG-2CD(-4PNIPAM) could self-assemble into nano-sized micelles. After the LCST transitions, PEG-2N3(-4PNIPAM) aggregated into micron-sized unstable particles, whereas PEG-2CD(-4PNIPAM) transformed into PNIPAM-cored nanomicelles. Besides, PEG-2CD(-4PNIPAM) can encapsulate doxorubicin below its LCST due to the formation of micelles.

• 出版日期2013-3-15
• 单位西北工业大学