Polyrotaxane-based triblock copolymers synthesized via ATRP of N-isopropylacrylamide initiated from the terminals of polypseudorotaxane of Br end-capped pluronic 17R4 and β-cyclodextrins  

作　　者：LI Shuo WANG Jin GAO Peng YE Lin ZHANG AiYing FENG Zeng-Guo 

机构地区：[1]School of Materials Science and Engineering Beijing Institute of Technology, Beijing 100081, China

出　　处：《Science China Chemistry》2012年第6期1115-1124,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (20974015);the Doctoral Program Foundation of Ministry of Education of China (20091101110029)

摘　　要：Thermo-responsive polyrotaxane （PR）-based triblock copolymers were synthesized via the atom transfer radical polymeriza- tion （ATRP） of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisobutyryl end-capped Plu- ronic 17R4 （PPOI4-PEG24-PPOI4） with a varying amount of β-cyclodextrins （β-CDs） in the presence of Cu（I）C1/PMDETA at 25 ~C in aqueous solution. The molecular structure was characterized by means of ~H NMR, FTIR, WXRD, GPC, TGA and DSC analyses. About half of [3-CDs are still entrapped on the Pluronic 17R4 chain while the number of incorporated NIPAAm monomers is nearly a double feed value in the resulting copolymers. The aggregate morphologies in aqueous solution were evidenced by TEM observations. A two-step thermo-responsive transition arising from a combination of a polypseudorotaxane middle block with poly（N-isopropylacrylamide） flanking blocks was also demonstrated by turbidity measurements. Given their thermo-responsive behavior in aqueous solution, these PR-based triblock copolymers show the potential to be used as smart materials for the controlled drug delivery systems, biosensors, and the like.Thermo-responsive polyrotaxane (PR)-based triblock copolymers were synthesized via the atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisobutyryl end-capped Pluronic 17R4 (PPO14-PEG24-PPO14) with a varying amount of β-cyclodextrins (β-CDs) in the presence of Cu(I)Cl/PMDETA at 25 °C in aqueous solution. The molecular structure was characterized by means of H NMR, FTIR, WXRD, GPC, TGA and 1 DSC analyses. About half of β-CDs are still entrapped on the Pluronic 17R4 chain while the number of incorporated NIPAAm monomers is nearly a double feed value in the resulting copolymers. The aggregate morphologies in aqueous solution were evidenced by TEM observations. A two-step thermo-responsive transition arising from a combination of a polypseudorotaxane middle block with poly(N-isopropylacrylamide) flanking blocks was also demonstrated by turbidity measurements. Given their thermo-responsive behavior in aqueous solution, these PR-based triblock copolymers show the potential to be used as smart materials for the controlled drug delivery systems, biosensors, and the like.

关 键 词：Β-CYCLODEXTRIN POLYROTAXANE ATRP poly（N-isopropylacrylamide） 

分 类 号：O633.22[理学—高分子化学] O632.13[理学—化学]