Polymerization-Induced Hierarchical Self-Assembly: From Monomer to Complex Colloidal Molecules and Beyond

Abstract

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 onestep process for the polymer synthesis and in situ self-assembly at high concentrations. Nevertheless, it is exceedingly challenging for the fabrication of hierarchical colloids via 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 via aqueous PISA that overcomes the limitation. Complex formation of water-immiscible monomers with cyclodextrin via "host−guest" inclusion, followed by sequential aqueous polymerization, provides a linear triblock terpolymer that can in situ 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 n -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 coreforming 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.

RAFT-mediated polymerization-induced self-assembly (RAFT-PISA): current status and future directions

“…In 2021, our group provided an innovative strategy to overcome the above problems and achieved a series of triblock terpolymer-based colloidal molecules, core–shell–corona micelles and raspberry-like particles via aqueous polymerization-induced hierarchical self-assembly (PIHSA). 34 As shown in Fig. 9a , in this study, dispersion polymerization of cyclodextrin (CD)–styrene water-soluble complex mediated by PEG-CDTPA was performed to obtain CAs.…”

“…17, 18 and 19) and silicone oil. 20 Up to now, many morphologies have been realized via PISA, including spheres, rods, worms, vesicles, framboidal vesicles, 21,22 multilamellar vesicles, 23 lamellae, 24 spongosomes, [25][26][27][28][29][30][31] hexosomes, [25][26][27]32 cubosomes, 25,26,32 Janus particles, 33,34 colloidal molecules, 33,34 and many others. The synthesized particles have a broad range of applications in the areas of biomedical, [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] coating, 54,55 catalysis [56][57][58][59][60] and Pickering emulsions…”

Confinement Assembly in Polymeric Micelles Enables Nanoparticle Superstructures with Tunable Molecular‐Like Geometries

“…We speculate that MnO NPs were oxidized in situ into hollow Mn 3 O 4 NPs while retaining the cluster structure. [ 21 ] This result also implies that the polymeric shell encapsulating NPs is permeable to solvent molecules, which helps to elucidate the self‐assembly mechanism of NPCs as described below.…”

“…[20] Besides, with rational structural design, block copolymers can self-assemble into colloidal molecules. [21] Other methodologies, such as covalent bonding [22,23] and photolithography, [5] are also used to manufacture NPCs. Chen and co-workers have systematically investigated the preparation of noble metal NPCs via electrostatic interactions or surface modification.…”

Divergent Synthesis of Biocompatible Nearly Monodisperse Multi‐Functional Poly(ethylene glycol) Periodic Copolymers

“…Copolymers of PEG (especially the linear, graft, and star copolymers) are generally prepared using ATRP, RAFT, and (anionic) ring opening copolymerization. [24][25][26][27] Anionic ROP of different functional epoxides (such as alkyl, tertiary amino) are well known in the context of the synthesis of the respective functional PEG with narrow dispersity. [28,29] Further secondary amine and ester groups in the PEG chains can be introduced via anionic ROP of aminal and ester-protected epoxides respectively and followed by a post-polymer deprotection.…”