Wan Jing, Fan Bo, Putera Kevin, Kim Jinhee, Banaszak Holl Mark M, Thang San H
ACS Nano. 2021 Aug 24;15(8):13721-13731. doi: 10.1021/acsnano.1c05089. Epub 2021 Aug 10.
The nanoscale hierarchical design that draws inspiration from nature's biomaterials allows the enhancement of material performance and enables multifarious applications. Self-assembly of block copolymers represents one of these artificial techniques that provide an elegant bottom-up strategy for the synthesis of soft colloidal hierarchies. Fast-growing polymerization-induced self-assembly (PISA) renders a one-step process for the polymer synthesis and self-assembly at high concentrations. Nevertheless, it is exceedingly challenging for the fabrication of hierarchical colloids aqueous PISA, simply because most monomers produce kinetically trapped spheres except for a few PISA-suitable monomers. We demonstrate here a sequential one-pot synthesis of hierarchically self-assembled polymer colloids with diverse morphologies aqueous PISA that overcomes the limitation. Complex formation of water-immiscible monomers with cyclodextrin "host-guest" inclusion, followed by sequential aqueous polymerization, provides a linear triblock terpolymer that can self-assemble into hierarchical nanostructures. To access polymer colloids with different morphologies, three types of linear triblock terpolymers were synthesized through this methodology, which allows the preparation of AX-type colloidal molecules (CMs), core-shell-corona micelles, and raspberry-like nanoparticles. Furthermore, the phase separations between polymer blocks in nanostructures were revealed by transmission electron microscopy and atomic force microscopy-infrared spectroscopy. The proposed mechanism explained how the interfacial tensions and glass transition temperatures of the core-forming blocks affect the morphologies. Overall, this study provides a scalable method of the production of CMs and other hierarchical structures. It can be applied to different block copolymer formulations to enrich the complexity of morphology and enable diverse functions of nano-objects.
从天然生物材料中汲取灵感的纳米级分层设计能够提升材料性能，并实现多种应用。嵌段共聚物的自组装是其中一种人工技术，为合成软胶体层次结构提供了一种精妙的自下而上策略。快速发展的聚合诱导自组装（PISA）为高浓度下的聚合物合成和自组装提供了一步法。然而，在水性PISA中制备分层胶体极具挑战性，仅仅是因为除了少数适合PISA的单体之外，大多数单体都会产生动力学捕获的球体。我们在此展示了一种在水性PISA中顺序一锅法合成具有多种形态的分层自组装聚合物胶体，克服了这一限制。与环糊精通过“主客体”包合形成水不混溶单体的复合物，随后进行顺序水相聚合，可提供一种能自组装成分层纳米结构的线性三嵌段三元共聚物。为了获得具有不同形态的聚合物胶体，通过这种方法合成了三种类型的线性三嵌段三元共聚物，这使得能够制备AX型胶体分子（CMs）、核壳冠层胶束和覆盆子状纳米颗粒。此外，通过透射电子显微镜和原子力显微镜 - 红外光谱揭示了纳米结构中聚合物嵌段之间的相分离。所提出的机制解释了成核嵌段的界面张力和玻璃化转变温度如何影响形态。总体而言，这项研究提供了一种可扩展的方法来生产CMs和其他分层结构。它可应用于不同的嵌段共聚物配方，以丰富形态的复杂性并实现纳米物体的多种功能。
