In Situ Synthesis of Branched Block Copolymer Assemblies via RAFT Dispersion Polymerization Using Branched Macro‐RAFT Agents^†

Abstract

Here, we demonstrate the use of branched macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agents in RAFT dispersion polymerization, to access branched block copolymers as well as well-defined branched block copolymer assemblies. Two types of branched macro-RAFT agents were first synthesized by using either a monofunctional chain transfer monomer or a difunctional chain transfer monomer in RAFT polymerization, and subsequently utilized in RAFT dispersion polymerization. It was found that only branched macro-RAFT agents synthesized from the difunctional chain transfer monomer could lead to colloidally stable assemblies with well-defined morphologies. Reaction conditions including monomer concentration, degree of polymerization (DP) of the core-forming block, and DP of the solvophilic segment on morphologies of branched block copolymer assemblies were investigated in detail. Size exclusion chromatography (SEC) analysis further confirmed the successful formation of branched block copolymers by using branched macro-RAFT agents. This work on the synthesis of branched block copolymer assemblies by RAFT dispersion polymerization offers new opportunities for the rational design of polymer assemblies with well-defined structures.

Polymerization‐induced self‐assembly for drug delivery: A critical appraisal

“…This additional compartmentalization opens up possibilities for co‐delivery of two different cargo types. Moreover, branched polymer structures can be included in the NP design 190 . Although more challenging to reproduce and characterize, branching offers an additional handle of control, for example, by promoting morphological transitions at lower DPs compared to linear BCPs 191,192 …”

From RAFT emulsion polymerization to RAFT dispersion polymerization: a facile approach to tuning dispersities and behaviors of self-assembled block copolymers

“…Over the past decade, RAFT–PISA has emerged as a powerful technique to prepare various block copolymer nanoparticles with high solids content (10–50%). 18–34 Moreover, RAFT–PISA is also a useful synthetic tool for the synthesis of well-defined polymers with low dispersities. 35–39 However, recent progress in controlling dispersities of polymers has shown that dispersity is also an important parameter that is used to tune properties of polymer materials.…”

Transitioning from Photoinitiation to Thermal Initiation in RAFT Dispersion Polymerization via a Small Modification of the Macro-RAFT Agent: A Scalable Approach for Monodisperse Surface-Functional Polymeric Microspheres

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