pH-Induced Micellization Kinetics of ABC Triblock Copolymers Measured by Stopped-Flow Light Scattering
pH-Induced Micellization Kinetics of ABC Triblock Copolymers Measured by Stopped-Flow Light Scattering
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DOI：
10.1021/ma051808c
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发表时间：
2005-10
期刊：
影响因子：
5.5
通讯作者：
Zhiyuan Zhu;S. Armes;Shiyong Liu
中科院分区：
文献类型：
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作者：
Zhiyuan Zhu;S. Armes;Shiyong Liu
通过原子转移自由基聚合（ATRP）合成了聚甲基丙烯酸甘油酯-聚甲基丙烯酸二甲氨基乙酯-聚甲基丙烯酸二乙氨基乙酯（GMA-DMA-DEA）三嵌段共聚物。采用停流光散射技术研究了该GMA−DMA−DEA三嵌段共聚物的pH诱导胶束化动力学。当pH值从4跳到7−7.5左右时，停流实验揭示了两个不同的弛豫过程。第一种弛豫模式具有正振幅，表明胶束尺寸和/或胶束数密度增加;相反，第二种弛豫模式具有负振幅，这归因于胶束形成-破裂过程。然而，当从pH 4跳到pH >8时，仅观察到具有正振幅的弛豫过程。弛豫曲线可以很好地用双指数函数拟合，导致快弛豫时间常数（τ1）和慢弛豫时间常数（τ2）。τ1在
A poly(glycerol monomethacrylate)-block-poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate) (GMA−DMA−DEA) triblock copolymer was synthesized via atom transfer radical polymerization (ATRP). The pH-induced micellization kinetics of this GMA−DMA−DEA triblock copolymer was investigated by employing a stopped-flow light scattering technique. Upon jumping from pH 4 to around 7−7.5, stopped-flow experiments revealed two distinct relaxation processes. The first relaxation mode had a positive amplitude, suggesting that the micelle size and/or micelle number density increases; in contrast, the second relaxation mode had a negative amplitude, which is assigned to the micelle formation−breakup process. However, upon jumping from pH 4 to pH >8, only relaxation processes with positive amplitude were observed. The relaxation curve can be well fitted with a double-exponential function, leading to a fast relaxation time constant (τ1) and a slow relaxation time constant (τ2). τ1 is in ...