Synthesis of controlled structure water-soluble diblock copolymers via oxyanionic polymerization
Synthesis of controlled structure water-soluble diblock copolymers via oxyanionic polymerization
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DOI：
10.1021/ma981779o
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发表时间：
1999-03-23
期刊：
影响因子：
5.5
通讯作者：
Armes, SP
中科院分区：
文献类型：
--
作者：
Vamvakaki, M;Billingham, NC;Armes, SP
导论.亲水性二嵌段共聚物的研究越来越受到人们的关注。这种共聚物可以（i）在水溶液中表现出可逆的胶束化行为，1r3（ii）作为广泛的颜料的分散剂，4（iii）影响无机材料如CaCO3的结晶，5（iv）用于合成具有亲水核的新型壳交联胶束，6和（v）具有生物医学应用。7我们对水溶性二嵌段共聚物，特别是基于甲基丙烯酸2-（二甲氨基）乙酯（DMAEMA）的二嵌段共聚物有着长期的兴趣。我们最近报道了几类新的基于DMAEMA的亲水性嵌段共聚物。9，10这种共聚物在25 ℃下在水溶液中以单聚体的形式分子溶解，而不需要助溶剂的帮助，并且在改变溶液温度或pH时进行可逆的胶束化。我们研究计划的长期目标是研究这种共聚物的胶束化和去胶束化的动力学。最近长崎等人报道，甲基丙烯酸2-（二乙基氨基）乙酯（DEAEMA）可以在环境温度下使用简单的醇盐引发剂如乙醇钾聚合。11日本研究小组认为，DEAEMA单体中的氮杂原子在其聚合反应中起着至关重要的作用，它与钾阳离子形成配位络合物，从而使氧阴离子更具反应性。虽然确切的机制仍然不清楚，我们已经聚合了各种叔胺甲基丙烯酸酯使用功能性的醇钾引发剂，以获得明确的大分子单体。[12]我们将这种合成路线称为"氧阴离子聚合"。本文中，我们报告了使用单羟基封端的聚-（环氧烷）作为大分子引发剂用于以下叔胺甲基丙烯酸酯的聚合（参见图1）：DMAEMA、DEAEMA、甲基丙烯酸2-（N-吗啉代）乙酯（MEMA）和甲基丙烯酸2-（二异丙基氨基）乙酯（DPAEMA）。这是一个有吸引力的合成路线，以新颖的亲水性-亲水性二嵌段共聚物，具有有趣的水溶液的性质。此外，其他工作者已经证明，相关的中性阳离子嵌段共聚物与DNA形成胶体聚集体，因此具有作为基因治疗应用的新型载体的一些潜力。13
Introduction. There is growing interest in hydrophilicrhydrophilic diblock copolymers. Such copolymers can (i) exhibit reversible micellization behavior in aqueous solution, 1r3 (ii) act as dispersants for a wide range of pigments, 4 (iii) influence the crystallization of inorganic materials such as CaCO3, 5 (iv) be utilized for the synthesis of novel shell cross-linked micelles with hydrophilic cores, 6 and (v) have biomedical applications. 7We have had a long-standing interest in water-soluble diblock copolymers, particularly those based on 2-(dimethylamino) ethyl methacrylate (DMAEMA). 8r10 We have recently reported several new classes of hydrophilicrhydrophilic block copolymers based on DMAEMA. 9, 10 Such copolymers dissolve molecularly as unimers in aqueous solution at 25 C without the aid of a cosolvent and undergo reversible micellization on altering the solution temperature or pH. A long-term goal of our research program is to study the kinetics of micellization and demicellization of such copolymers. Recently Nagasaki et al. reported that 2-(diethylamino) ethyl methacrylate (DEAEMA) can be polymerized at ambient temperature using simple alcoholate initiators such as potassium ethoxide. 11 The Japanese group suggested that the nitrogen heteroatom of the DEAEMA monomer played a crucial role in its polymerization by forming a coordination complex with the potassium cation, thus making the oxyanion more reactive. Although the precise mechanism remains unclear, we have polymerized various tertiary amine methacrylates using functional potassium alcoholate initiators in order to obtain well-defined macromonomers. 12 We have termed this synthetic route “oxyanionic polymerization”. Herein we report the use of monohydroxy-capped poly-(alkylene oxide) s as macroinitiators for the polymerization of the following tertiary amine methacrylates (see Figure 1): DMAEMA, DEAEMA, 2-(N-morpholino) ethyl methacrylate (MEMA), and 2-(diisopropylamino) ethyl methacrylate (DPAEMA). This is an attractive synthetic route to novel hydrophilic-hydrophilic diblock copolymers which have interesting aqueous solution properties. Furthermore, other workers have demonstrated that related neutralrcationic block copolymers form colloidal aggregates with DNA and therefore have some potential as novel vectors for gene therapy applications. 13