Ratcliffe Liam P D, Derry Matthew J, Ianiro Alessandro, Tuinier Remco, Armes Steven P
Department of Chemistry, Dainton Building, University of Sheffield, Brook Hill, South Yorkshire, S3 7HF, UK.
Present address: Unilever Research & Development, Colworth Laboratory, Colworth House, Sharnbrook, Bedford, MK44 1LQ, UK.
Angew Chem Int Ed Engl. 2019 Dec 19;58(52):18964-18970. doi: 10.1002/anie.201909124. Epub 2019 Nov 6.
It is well-known that the self-assembly of AB diblock copolymers in solution can produce various morphologies depending on the relative volume fraction of each block. Recently, polymerization-induced self-assembly (PISA) has become widely recognized as a powerful platform technology for the rational design and efficient synthesis of a wide range of block copolymer nano-objects. In this study, PISA is used to prepare a new thermoresponsive poly(N-(2-hydroxypropyl) methacrylamide)-poly(2-hydroxypropyl methacrylate) [PHPMAC-PHPMA] diblock copolymer. Remarkably, TEM, rheology and SAXS studies indicate that a single copolymer composition can form well-defined spheres (4 °C), worms (22 °C) or vesicles (50 °C) in aqueous solution. Given that the two monomer repeat units have almost identical chemical structures, this system is particularly well-suited to theoretical analysis. Self-consistent mean field theory suggests this rich self-assembly behavior is the result of the greater degree of hydration of the PHPMA block at lower temperature, which is in agreement with variable temperature H NMR studies.
众所周知，AB型二嵌段共聚物在溶液中的自组装可根据每个嵌段的相对体积分数产生各种形态。最近，聚合诱导自组装（PISA）已被广泛认为是一种强大的平台技术，用于合理设计和高效合成各种嵌段共聚物纳米物体。在本研究中，PISA用于制备一种新型的热响应性聚（N-（2-羟丙基）甲基丙烯酰胺）-聚（甲基丙烯酸2-羟丙酯）[PHPMAC-PHPMA]二嵌段共聚物。值得注意的是，透射电子显微镜（TEM）、流变学和小角X射线散射（SAXS）研究表明，单一的共聚物组成在水溶液中可形成明确的球体（4℃）、蠕虫状（22℃）或囊泡（50℃）。鉴于这两个单体重复单元具有几乎相同的化学结构，该体系特别适合进行理论分析。自洽平均场理论表明，这种丰富的自组装行为是由于PHPMA嵌段在较低温度下具有更高程度的水合作用，这与变温核磁共振氢谱（H NMR）研究结果一致。
