“Schizophrenic” Micelles from Doubly Thermoresponsive Polysulfobetaine-b-poly(N-isopropylmethacrylamide) Diblock Copolymers
“Schizophrenic” Micelles from Doubly Thermoresponsive Polysulfobetaine-b-poly(N-isopropylmethacrylamide) Diblock Copolymers
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DOI：
10.1021/acs.macromol.7b00356
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发表时间：
2017-05
期刊：
影响因子：
5.5
通讯作者：
N. Vishnevetskaya;Viet Hildebrand;Bart‐Jan Niebuur;I. Grillo;S. Filippov;A. Laschewsky;P. Müller‐Buschbaum;C. Papadakis
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作者：
N. Vishnevetskaya;Viet Hildebrand;Bart‐Jan Niebuur;I. Grillo;S. Filippov;A. Laschewsky;P. Müller‐Buschbaum;C. Papadakis
通过连续RAFT聚合制备了由两性离子型聚磺基甜菜碱（PSPP）和非离子型聚（N-异丙基甲基丙烯酰胺）（PNIPMAM）嵌段组成的双重温敏性嵌段共聚物PSPP 498-b-PNIPMAM 144。它结合了上，下临界溶解温度（UCST和LCST）的行为，分别在水溶液中的本构均聚物。我们调查的温度依赖性的相行为和自组装结构的嵌段共聚物在D2 O的浊度法和小角中子散射（SANS）在无盐溶液中，并在存在少量的NaCl和NaBr。为了比较，PNIPMAM均聚物在D2 O中的溶液也被研究。比浊法表明PSPP 498-b-PNIPMAM 144的热诱导“精神分裂”聚集行为。SANS结果表明，在LCST转变点以上形成了传统的星形核壳胶束结构，而在UCST转变点以下，结构的形成要少得多。
The 2-fold thermoresponsive diblock copolymer PSPP498-b-PNIPMAM144, which consists of a zwitterionic polysulfobetaine (PSPP) block and a nonionic poly(N-isopropylmethacrylamide) (PNIPMAM) block, is prepared by consecutive RAFT polymerizations. It combines the upper and lower critical solution temperature (UCST and LCST) behaviors, respectively, of the constitutive homopolymers in aqueous solution. We investigate the temperature-dependent phase behavior and the self-assembled structures of the block copolymer in D2O by turbidimetry and by small-angle neutron scattering (SANS) in salt-free solution and in the presence of small amounts of NaCl and NaBr. For comparison, solutions of PNIPMAM homopolymer in D2O are studied as well. Turbidimetry indicates thermally induced “schizophrenic” aggregation behavior for PSPP498-b-PNIPMAM144. SANS reveals that conventional star-like core–shell micellar structures are formed above the LCST transition, whereas below the UCST-transition, structure formation is much less pr...