Laboratoire de Chimie des Polymères Organiques, Université de Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600 Pessac, France.
Molecules. 2021 Mar 5;26(5):1412. doi: 10.3390/molecules26051412.
The ability of bottlebrush block copolymers (BBCPs) to self-assemble into ordered large periodic structures could greatly expand the scope of photonic and membrane technologies. In this paper, we describe a two-step synthesis of poly(l-lactide)--polystyrene (PLLA--PS) BBCPs and their rapid thin-film self-assembly. PLLA chains were grown from -5-norbornene-2-methanol via ring-opening polymerization (ROP) of l-lactide to produce norbornene-terminated PLLA. Norbonene-terminated PS was prepared using anionic polymerization followed by a termination reaction with -5-norbornene-2-carbonyl chloride. PLLA--PS BBCPs were prepared from these two norbornenyl macromonomers by a one-pot sequential ring opening metathesis polymerization (ROMP). PLLA--PS BBCPs thin-films exhibited cylindrical and lamellar morphologies depending on the relative block volume fractions, with domain sizes of 46-58 nm and periodicities of 70-102 nm. Additionally, nanoporous templates were produced by the selective etching of PLLA blocks from ordered structures. The findings described in this work provide further insight into the controlled synthesis of BBCPs leading to various possible morphologies for applications requiring large periodicities. Moreover, the rapid thin film patterning strategy demonstrated (>5 min) highlights the advantages of using PLLA--PS BBCP materials beyond their linear BCP analogues in terms of both dimensions achievable and reduced processing time.
瓶刷嵌段共聚物（BBCPs）能够自组装成有序的大周期性结构，这极大地扩展了光子学和膜技术的应用范围。本文描述了聚（L-丙交酯）-聚苯乙烯（PLLA-PS）BBCPs 的两步合成及其快速的薄膜自组装过程。PLLA 链通过 L-丙交酯的开环聚合（ROP）从-5-降冰片烯-2-甲醇中生长，得到封端的 norbornene-PLLA。通过阴离子聚合制备 norbornene-PS，然后用-5-降冰片烯-2-羰基氯进行封端反应。通过一锅法顺序开环复分解聚合（ROMP）从这两种 norbornenyl 大分子单体制备 PLLA-PS BBCPs。PLLA-PS BBCPs 薄膜表现出圆柱状和层状形貌，这取决于相对嵌段体积分数，其畴尺寸为 46-58nm，周期为 70-102nm。此外，通过对有序结构中 PLLA 嵌段的选择性刻蚀，制备出了纳米多孔模板。本工作中的发现进一步深入了解了 BBCPs 的可控合成，为需要大周期性的各种应用提供了不同的可能形貌。此外，所展示的快速薄膜图案化策略（<5min）突出了 PLLA-PS BBCP 材料相对于其线性嵌段共聚物的优势，不仅在可实现的尺寸方面，而且在加工时间方面都得到了简化。
