Synthesis and aqueous solution properties of near-monodisperse tertiary amine methacrylate homopolymers and diblock copolymers
Synthesis and aqueous solution properties of near-monodisperse tertiary amine methacrylate homopolymers and diblock copolymers
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DOI：
10.1016/s0032-3861(01)00066-0
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发表时间：
2001-06-01
期刊：
影响因子：
4.6
通讯作者：
Billingham, NC
中科院分区：
文献类型：
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作者：
Bütün, V;Armes, SP;Billingham, NC
甲基丙烯酸叔胺、甲基丙烯酸2-(二甲氨基)乙酯(DMA)、甲基丙烯酸-2-(二乙氨基)乙酯(DEA)、甲基丙烯酸-2-(二异丙氨基)乙酯(DPA)和甲基丙烯酸-2-(N-吗啉基)乙酯(MEMA)的基团转移聚合(GTP)得到了一系列近单分散的均聚物(MW/MN<；1.15)。通过改变单体/引发剂比例来控制聚合物的相对分子质量。在20℃时，DMA和MEMA均聚物在酸性或中性介质中均可溶于水。在更高的温度下观察到相反的温度溶解行为，在pH 8时，浊点在32-53℃之间。正如预期的那样，浊点随着聚合度的增加而单调下降。MEMA均聚物对添加的电解液特别敏感，当添加0.2-0.3M的Na2SO4时，在20℃下会发生盐析。疏水性较强的DEA和DPA均聚物在20℃和中性pH下均不溶于水，但由于叔胺残基的质子化作用，它们在酸性介质中很容易以阳离子聚电解质的形式溶解。此外，DNA还依次与其他三种甲基丙烯酸叔胺共聚单体进行嵌段共聚。这些两嵌段共聚物可以在20℃的温度下在没有共溶剂的情况下在水介质中以分子形式溶解，适当调整溶液的pH、温度或电解质浓度即可实现可逆的胶束化。在这三种情况下，均形成了稳定的嵌段共聚胶束，具有DMA冠状结构，流体力学直径为20-60 nm。(C)2001爱思唯尔科学有限公司。保留所有权利。
Group transfer polymerisation (GTP) of four tertiary amine methacrylates, 2-(dimethylamino)ethyl methacrylate (DMA), 2-(diethylamino)ethyl methacrylate (DEA), 2-(diisopropylamino)ethyl methacrylate (DPA) and 2-(N-morpholino)ethyl methacrylate (MEMA) produced a series of near-monodisperse homopolymers (Mw/Mn < 1.15). Molecular weights were controlled by varying the monomer/initiator ratio. The DMA and MEMA homopolymers were both water-soluble at 20C in acidic or neutral media. Inverse temperature solubility behaviour was observed at higher temperatures, with cloud-points ranging from 32 to 53 degreesC at pH 8. The Cloud-points decreased monotonically with increasing degrees of polymerisation, as expected. The MEMA homopolymers were particularly sensitive to the added electrolyte, with 'salting out' occurring at 20 degreesC on addition of 0.2-0.3 M Na2SO4. The more hydrophobic DEA and DPA homopolymers were both insoluble at 20 degreesC and neutral pH but readily dissolved as cationic polyelectrolytes in acidic media due to protonation of the tertiary amine residues. In addition, DNA was block copolymerized in turn with each of the other three tertiary amine methacrylate comonomers. These diblock copolymers could be dissolved molecularly without co-solvents in aqueous media at 20 degreesC, with micellization occurring reversibly on judicious adjustment of the solution pH, temperature or electrolyte concentration. In all three cases, stable block copolymer micelles were formed with DMA coronas and hydrodynamic diameters of 20-60 nm. (C) 2001 Elsevier Science Ltd. All rights reserved.