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Interplay of Thermosensitivity and pH Sensitivity of Amphiphilic Block–Gradient Copolymers of Dimethylaminoethyl Acrylate and Styrene
Macromolecules ( IF 5.1 ) Pub Date : 2018-07-09 00:00:00 , DOI: 10.1021/acs.macromol.8b00621
Mariia Rabyk 1 , Aurélie Destephen 2 , Alain Lapp 3 , Stephen King 4 , Laurence Noirez 3 , Laurent Billon 2, 5 , Martin Hruby 1 , Oleg Borisov 2 , Petr Stepanek 1 , Elise Deniau 2
Affiliation  

Novel pH- and thermoresponsive amphiphilic diblock copolymer, comprising hydrophilic poly(2-dimethylaminoethyl acrylate) (PDMAEA) and amphiphilic poly(styrene-grad-2-dimethylaminoethyl acrylate) (P(S-grad-DMAEA)) blocks, was synthesized by nitroxide-mediated radical polymerization. A series of copolymers (PS-grad-PDMAEA) with controlled molar masses and low dispersities over a wide range of monomer feed ratios (0 < fS,0 < 1) were synthesized. Both conventional linearization and nonlinear least-squares methods were applied to estimate reliable values of the reactivity ratios for S and DMAEA radical polymerization. The calculated values of the reactivity ratios (rDMAEA = 0.25 and rS = 1.15) perfectly fitted the drift in monomer feed ratio versus conversion, showing a gradient distribution along the copolymer chains. The self-assembling behavior of the copolymers in the aqueous medium was investigated by dynamic light scattering and small-angle neutron scattering over a wide range of pH, temperature, and salt concentration. These block-gradient copolymers show reversible self-association into micelle-like structure (Dh ∼ 20 nm) in aqueous solutions triggered by both pH and temperature.

中文翻译:

丙烯酸二甲氨基乙基酯和苯乙烯的两亲嵌段共聚物的热敏性和pH敏感性之间的相互作用

新颖pH-和热反应性两亲性嵌段共聚物,其包含亲水性聚(2-二甲基氨基乙基丙烯酸酯)(PDMAEA)和两亲性聚(苯乙烯研究所-2-二甲基氨基乙酯)(P(S-研究所-DMAEA))的块,被氮氧化物合成介导的自由基聚合。合成了一系列在宽范围的单体进料比(0 < f S,0 <1)下具有可控的摩尔质量和低分散性的共聚物(PS- grad -PDMAEA)。常规线性化方法和非线性最小二乘法均用于估算S和DMAEA自由基聚合反应率的可靠值。反应性比的计算值(r DMAEA = 0.25和r S = 1.15)完全符合单体进料比与转化率之间的漂移关系,显示出沿共聚物链的梯度分布。通过动态光散射和小角度中子散射在广泛的pH,温度和盐浓度范围内研究了共聚物在水性介质中的自组装行为。这些嵌段梯度共聚物在pH和温度共同作用下,在水溶液中表现出可逆的自缔合成胶束状结构(D h〜20 nm)。
更新日期:2018-07-09
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