Copper(II)/Tertiary Amine Synergy in Photoinduced Living Radical Polymerization: Accelerated Synthesis of ω-Functional and α,ω-Heterofunctional Poly(acrylates)
Copper(II)/Tertiary Amine Synergy in Photoinduced Living Radical Polymerization: Accelerated Synthesis of ω-Functional and α,ω-Heterofunctional Poly(acrylates)
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DOI：
10.1021/ja411780m
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发表时间：
2014-01-22
影响因子：
15
通讯作者：
Haddleton, David M.
中科院分区：
文献类型：
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作者：
Anastasaki, Athina;Nikolaou, Vasiliki;Haddleton, David M.
在不存在常规光引发剂或染料敏化剂的情况下，丙烯酸酯的光诱导活性自由基聚合已经在“日光”下实现，并且在用UV辐射（λ（max）接近360 nm）照射时增强。在低浓度溴化铜（II）和脂肪族叔胺配体（Me-6-Tren; Tren =三（2-氨基乙基）胺）的存在下，在80分钟内获得接近定量的单体转化率（>95%），产生具有低至1.05的分散度和优异的端基保真度（>99%）的聚丙烯酸酯。该技术的通用性通过丙烯酸甲酯聚合至一定范围的链长（DPn = 25-800）和许多（甲基）丙烯酸酯单体（包括大分子单体聚（乙二醇）甲基醚丙烯酸酯（PEGA（480））、丙烯酸叔丁酯和甲基丙烯酸甲酯以及苯乙烯）来证明。此外，羟基和邻二醇官能引发剂与聚合条件相容，以无与伦比的效率和控制形成α，ω-杂官能聚丙烯酸酯。通过MALDI-ToF-MS证实了聚合过程中保留的控制，并通过顺序加入单体后的原位扩链来举例说明，提供了具有观察到的分散性降低（D = 1.03）的较高分子量聚合物。类似地，还报道了通过将乙二醇甲基醚丙烯酸酯和PEGA（480）顺序加入到聚（丙烯酸甲酯）大分子引发剂中而无需预先处理或纯化的有效的一锅法二嵌段共聚。在没有光的情况下的最小聚合赋予时间控制，并暗示在材料化学的前沿之一的潜在应用，从而精确的时空“开/关”控制和分辨率是理想的。
Photoinduced living radical polymerization of acrylates, in the absence of conventional photoinitiators or dye sensitizers, has been realized in "daylight'" and is enhanced upon irradiation with UV radiation (lambda(max) approximate to 360 nm). In the presence of low concentrations of copper(II) bromide and an aliphatic tertiary amine ligand (Me-6-Tren; Tren = tris(2-aminoethyl)amine), near-quantitative monomer conversion (>95%) is obtained within 80 min, yielding poly(acrylates) with dispersities as low as 1.05 and excellent end group fidelity (>99%). The versatility of the technique is demonstrated by polymerization of methyl acrylate to a range of chain lengths (DPn = 25-800) and a number of (meth)acrylate monomers, including macromonomer poly(ethylene glycol) methyl ether acrylate (PEGA(480)), tert-butyl acrylate, and methyl methacrylate, as well as styrene. Moreover, hydroxyl- and vic-diol-functional initiators are compatible with the polymerization conditions, forming alpha,omega-heterofunctional poly(acrylates) with unparalleled efficiency and control. The control retained during polymerization is confirmed by MALDI-ToF-MS and exemplified by in situ chain extension upon sequential monomer addition, furnishing higher molecular weight polymers with an observed reduction in dispersity (D = 1.03). Similarly, efficient one-pot diblock copolymerization by sequential addition of ethylene glycol methyl ether acrylate and PEGA(480) to a poly(methyl acrylate) macroinitiator without prior workup or purification is also reported. Minimal polymerization in the absence of light confers temporal control and alludes to potential application at one of the frontiers of materials chemistry whereby precise spatiotemporal "on/off' control and resolution is desirable.