ABC triblock copolymers with a poly(ethylene glycol) (PEG) midblock have attractive properties for biomedical applications because of PEG’s favorable properties regarding biocompatibility and hydrophilicity. However, easy strategies to synthesize polymers containing a PEG midblock are limited. In this study, the successful synthesis of a heterofunctional PEG macroinitiator containing both an azoinitiator and an atom transfer radical polymerization (ATRP) initiator is demonstrated. This novel PEG macroinitiator allows the development of elegant synthesis routes for PEG midblock-containing ABC copolymers that does not require protection of initiating sites or polymer end-group postmodification. Polymers with outer blocks composed of different monomers were synthesized to illustrate the versatility of this macroinitiator. N-Isopropylacrylamide (NIPAM) was included to obtain thermosensitive polymers, 2-(dimethylamino)ethyl methacrylate (DMAEMA) provided pH-sensitive properties, and 2-hydroxyethyl acrylate (HEA) functioned as a noncharged hydrophilic block that also allows for postmodifications reactions. This synthesis approach can further contribute to the design of high-precision polymers with tailorable block compositions and polymer topologies, which is highly attractive for applications in nanotechnology.

中文翻译：

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能够控制ABC三嵌段共聚物合成的杂官能聚（乙二醇）（PEG）大分子引发剂

ABC三嵌段共聚物与聚（乙二醇）（PEG）中间嵌段具有吸引人的生物医学应用性能，因为PEG在生物相容性和亲水性方面具有良好的性能。然而，合成包含PEG中间嵌段的聚合物的简单策略受到限制。在这项研究中，成功​​合成了同时包含偶氮引发剂和原子转移自由基聚合（ATRP）引发剂的杂功能PEG大分子引发剂。这种新颖的PEG大分子引发剂为含PEG中间嵌段的ABC共聚物开发了优雅的合成路线，该路线不需要保护起始位点或聚合物端基后改性。合成了具有由不同单体组成的外部嵌段的聚合物，以说明该大分子引发剂的多功能性。ñ包括异丙基丙烯酰胺（NIPAM）以得到热敏聚合物，甲基丙烯酸2-（二甲氨基）乙酯（DMAEMA）提供pH敏感特性，丙烯酸2-羟乙酯（HEA）用作不带电荷的亲水性嵌段，还可以进行后修饰反应。这种合成方法可进一步有助于设计具有可调整嵌段组成和聚合物拓扑结构的高精度聚合物，这对纳米技术的应用极具吸引力。