Versatile Synthesis of Multiarm and Miktoarm Star Polymers with a Branched Core by Combination of Menschutkin Reaction and Controlled Polymerization

Abstract

Menschutkin reaction and controlled polymerization were combined to construct three types of star polymers with a branched core. Branched PVD was synthesized by reversible addition–fragmentation chain transfer (RAFT) copolymerization and used as a core reagent to synthesize multiarm and miktoarm stars with poly(ε-caprolactone) (PCL), polystyrene, poly(methyl methacrylate), poly(tert-butyl acrylate), and poly(N-isopropylacrylamide) segments. Effects of reaction time, feed ratio, and arm length on coupling reaction between PVD and bromide-functionalized polymer were investigated, and a variety of A m -type stars (m ≈ 7.0–35.1) were obtained. Meanwhile, A m B n stars (m ≈ 9.0, n ≈ 6.1–11.3) were achieved by successive Menschutkin reactions, and A m C o stars (m ≈ 8.8–9.0, o ≈ 5.0) were generated by tandem quaternization and RAFT processes. Molecular weights of various stars usually agreed well with the theoretical values, and their polydispersity indices were in the range of 1.06–1.24. The arm number, chain length, and chemical composition of star polymers could be roughly adjusted by control over reaction conditions and utilization of alternative methods, revealing the generality and versatility of these approaches. These ion-bearing stars were liable to exhibit solubility different from normal covalently bonded polymers, and the chain relaxation and melting behaviors of polymer segments were strongly dependent on the macromolecular architecture.

Emerging Synthetic Strategies for Core Cross‐Linked Star (CCS) Polymers and Applications as Interfacial Stabilizers: Bridging Linear Polymers and Nanoparticles

“…Star polymers with a number of arms connecting to a central core are considered as the simplest type of branched polymers. Since there are numerous polymers in the literature that are called “star,” “star‐like,” or “dendritic star” polymers, in this article, we restrict our discussion of star polymers to those in which the core dimension is smaller than that of the arms . Although there is no clear definition existing on the relative size of the core and the arm for star polymer, we tentatively suggest that a core with a mass or degree of polymerization being less than 30% of the total mass or total degree of polymerization of the polymer chains constituting the star polymer should be used to make a first judgment.…”

Synthesis of Highly Branched Copolymers in Microemulsion

“…Among the various synthetic methods, radical‐based self‐condensing vinyl polymerization (SCVP) of inimers (containing ini tiator fragment and mono mer vinyl group in one molecule) and/or transmers (containing chain trans fer group and mono mer vinyl group in one molecule) has become particularly popularly in the past two decades. All established reversible deactivation radical polymerizations (RDRP) techniques, including atom transfer radical polymerization (ATRP), nitroxide‐mediated polymerization (NMP) and reversible addition–fragmentation chain transfer (RAFT) polymerization have been intensively applied in the (co)polymerization of inimers and transmers, primarily in solution, for synthesis of branched polymers with various compositions. For instance, those synthesized by ATRP possess high density of chain‐end initiating groups and are easy to extend with vinyl monomers using the same technique .…”

Temperature‐Sensitive (BA)(AC)2 Miktoarm Star Diblock Copolymer Based on PMMA, PPEGMA, and PNIPAm

“…[1][2][3][4][5][6][7] Compared with their linear counterparts, star polymers exhibit unique morphologies, properties, and functions, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] especially miktoarm star polymers. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] This is because a miktoarm star polymer combines different polymer arms into a molecule through a single core.…”

“…Star polymers refer to those composed of the same or various types of polymer arms emanating from a core . Compared with their linear counterparts, star polymers exhibit unique morphologies, properties, and functions, especially miktoarm star polymers . This is because a miktoarm star polymer combines different polymer arms into a molecule through a single core.…”