Flow chemistry controls self-assembly and cargo in Belousov-Zhabotinsky driven polymerization-induced self-assembly

Liman Hou,Rohit Srivastava,Juan Pérez-Mercader,Marta Dueñas-Díez

doi:10.1038/s42004-019-0241-1

Liman Hou, Rohit Srivastava + Show 2 more

Open Access

https://doi.org/10.1038/s42004-019-0241-1

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Abstract

Amphiphilic block-copolymer vesicles are increasingly used for medical and chemical applications, and a novel method for their transient self-assembly orchestrated by periodically generated radicals during the oscillatory Belousov-Zhabotinsky (BZ) reaction was recently developed. Here we report how combining this one pot polymerization-induced self-assembly (PISA) method with a continuously stirred tank reactor (CSTR) strategy allows for continuous and reproducible control of both the PISA process and the chemical features (e.g. the radical generation and oscillation) of the entrapped cargo. By appropriately tuning the residence time (τ), target degree of polymerization (DP) and the BZ reactants, intermediate self-assembly structures are also obtained (micelles, worms and nano-sized vesicles). Simultaneously, the chemical properties of the cargo at encapsulation are known and tunable, a key advantage over batch operation. Finally, we also show that BZ-driven polymerization in CSTR additionally supports more non-periodic dynamics such as bursting.

Highlights

Amphiphilic block-copolymer vesicles are increasingly used for medical and chemical applications, and a novel method for their transient self-assembly orchestrated by periodically generated radicals during the oscillatory Belousov-Zhabotinsky (BZ) reaction was recently developed
It should be noted that the BZ chemical initiation of the polymerization has some advantages over thermal initiation, most of which are shared with photoinitiation methods: BZ is run at low temperatures, is oxygen tolerant, runs in open-air conditions in aqueous medium, and the catalyst is not consumed during polymerization but continuously and periodically regenerated through the chemical oscillations
Available diacetone acrylamide (DAAM) was used as a monomer known to be water-miscible at room temperature, yet its polymer is water-insoluble and has previously been reported to be a monomer for PISA49,50

Summary

Introduction

Amphiphilic block-copolymer vesicles are increasingly used for medical and chemical applications, and a novel method for their transient self-assembly orchestrated by periodically generated radicals during the oscillatory Belousov-Zhabotinsky (BZ) reaction was recently developed. In a typical PISA setting, in a batch reactor, a soluble polymer is chain-extended with a second monomer to form amphiphilic diblock copolymers that can further undergo self-assembly into a range of morphologies[14,15]. PISA has been shown to take place when coupling the periodically generated radicals from an oscillating BZ reaction to chain- extend a hydrophilic PEG macroCTA to form an amphiphilic copolymer that further self-assembled into blebbing and dividing polymer vesicles[21,22]. The catalyst regeneration can be tuned to a large extent and through a variety of operating variables that influence radical production, Potential a Control Monitor Module

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