Synthesis of Polypeptoid-Polycaprolactone-Polytetrahydrofuran Heterograft Molecular Polymer Brushes via a Combination of Janus Polymerization and ROMP
Synthesis of Polypeptoid-Polycaprolactone-Polytetrahydrofuran Heterograft Molecular Polymer Brushes via a Combination of Janus Polymerization and ROMP
复制标题
Janus聚合与ROMP相结合合成多肽-聚己内酯-聚四氢呋喃异质接枝分子聚合物刷
DOI：
10.1002/marc.201800905
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发表时间：
2019
影响因子：
4.6
通讯作者：
Ling Jun
中科院分区：
文献类型：
--
作者：
Li Yao;Schacher Felix H;Ling Jun
Janus聚合是一种利用Lu(OTf)3和环氧丙烷作为催化体系一步合成二嵌段和多嵌段共聚物的新颖有效的方法。通过修改位于不同官能团嵌段连接处的环氧化物引发剂，为未来的拓扑设计提供了可能性。本文中，2-双环[2.2.1]庚-5-en-2-基环氧乙烷（NB-EO）用作环氧丙烷的替代品，合成了在该位置具有降冰片烯基团的聚（THF-co-CL）-b-PCL二嵌段共聚物。这也导致通过Janus聚合产生带有多个降冰片烯部分的多嵌段[聚(THF-co-CL)-b-PCL]聚合物。随后将所得聚(THF-co-CL)-b-PCL大单体与降冰片烯基封端的聚肌氨酸(PSar-NB)进行开环复分解共聚(ROMP)，可以轻松制备异质接枝分子聚合物刷(MPB)。 MPB 具有 PCL、P(CL-co-THF) 和 PSar 的三种异质接枝物，可能使这些结构具有生物相容性、生物可降解性、半结晶性和两亲性。退火后在 TEM 和 AFM 分析中均观察到相分离。由于其两亲性质，MPB 也会在水溶液中自组装成胶束。这种结合了多肽、聚酯和聚醚片段的材料预计将在药物输送应用中引起广泛关注。
Janus polymerization is a novel and efficient way to synthesize diblock and multiblock copolymers in one step by using Lu(OTf)3and propylene epoxide as a catalytic system. By modifying the epoxide initiator, which is located at the block junction with various functional groups, the possibility for future topological design is provided. Herein, 2‐bicyclo[2.2.1]hept‐5‐en‐2‐yl oxirane (NB‐EO) is used as an alternative for propylene epoxide to synthesize a poly(THF‐co‐CL)‐b‐PCL diblock copolymer featuring a norbornene group at this position. This also results in multiblock [poly(THF‐co‐CL)‐b‐PCL]mcopolymers carrying multiple norbornene moieties through Janus polymerization. Subsequent ring‐opening metathesis copolymerization (ROMP) of the resulting poly(THF‐co‐CL)‐b‐PCL macromonomers with norbornenyl‐terminated polysarcosine (PSar‐NB) allows the facile preparation of heterograft molecular polymer brushes (MPBs). The MPBs feature three heterografts of PCL, P(CL‐co‐THF) and PSar, potentially equipping these structures with biocompatibility, biodegradability, semi‐crystallinity, and amphiphilicity. A phase separation is observed after annealing in both TEM and AFM analysis. Due to their amphiphilic nature, the MPBs also undergo self‐assembly into micelles in aqueous solution. Such materials combining polypeptoids, polyesters, and polyethers segments are expected to attract wide attention in drug delivery applications.