Neal Thomas J, Penfold Nicholas J W, Armes Steven P
Department or Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK.
Angew Chem Int Ed Engl. 2022 Aug 15;61(33):e202207376. doi: 10.1002/anie.202207376. Epub 2022 Jul 6.
We report a new aqueous polymerization-induced self-assembly (PISA) formulation that enables the hydrophobic block to be prepared first when targeting diblock copolymer nano-objects. This counter-intuitive reverse sequence approach uses an ionic reversible addition-fragmentation chain transfer (RAFT) agent for the RAFT aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) to produce charge-stabilized latex particles. Chain extension using a water-soluble methacrylic, acrylic or acrylamide comonomer then produces sterically stabilized diblock copolymer nanoparticles in an aqueous one-pot formulation. In each case, the monomer diffuses into the PHPMA particles, which act as the locus for the polymerization. A remarkable change in morphology occurs as the ≈600 nm latex is converted into much smaller sterically stabilized diblock copolymer nanoparticles, which exhibit thermoresponsive behavior. Such reverse sequence PISA formulations enable the efficient synthesis of new functional diblock copolymer nanoparticles.
我们报道了一种新的水相聚合诱导自组装（PISA）配方，在制备二嵌段共聚物纳米物体时，该配方能够先制备疏水嵌段。这种违反直觉的反向顺序方法使用离子可逆加成-断裂链转移（RAFT）试剂，通过甲基丙烯酸羟丙酯（HPMA）的RAFT水分散聚合来制备电荷稳定的乳胶颗粒。然后使用水溶性甲基丙烯酸、丙烯酸或丙烯酰胺共聚单体进行链增长，在水相一锅法配方中制备空间稳定的二嵌段共聚物纳米颗粒。在每种情况下，单体扩散到PHPMA颗粒中，这些颗粒作为聚合反应的场所。当约600 nm的乳胶转化为更小的、表现出热响应行为的空间稳定二嵌段共聚物纳米颗粒时，形态会发生显著变化。这种反向顺序PISA配方能够高效合成新型功能性二嵌段共聚物纳米颗粒。
