Synthesis of a sun-shaped amphiphilic copolymer consisting of a cyclic perfluorocyclobutyl aryl ether-based backbone and lateral PMAA side chains

Abstract

A novel amphiphilic sun-shaped copolymer, c-PMBTFVB-g-PMAA (MBTFVB: 2-methyl-1,4-bistrifluorovinyloxybenzene, MAA: methacrylic acid) containing cyclic perfluorocyclobutyl (PFCB) aryl ether-based backbone and PMAA lateral side chains with narrow molecular weight distribution (M w /M n ≤1.38), was synthesized via the site transformation strategy. First, PMBTFVB linear precursor was prepared by step-growth thermal cycloaddtion polymerization of MBTFVB trifluorovinyl monomer. After the end functionalization of linear precursor with alkyne, Glaser coupling reaction was performed to produce c-PMBTFVB cyclic homopolymer. The pendant methyls on PFCB aryl ether-based backbone were then converted to Br-containing ATRP initiating groups by a mono-bromination reaction with N-bromosuccinimide (NBS) and benzoyl peroxide (BPO) to give c-PMBTFVB-Br cyclic macroinitiator without affecting the main chain, where the density of ATRP initiation groups could be tuned from 33% to 58% by the feeding ratio of NBS to the pendant methyl. Subsequently, c-PMBTFVB-g-PMAA sun-shaped amphiphilic copolymers with hydrophilic PMAA side chains were synthesized by ATRP of tert-butyl methacrylate (tBMA) initiated by c-PMBTFVB-Br, followed by the selective hydrolysis of hydrophobic PtBMA segment into hydrophilic PMAA segment using CF 3 COOH. The obtained c-PMBTFVB cyclic homopolymer and its precursor were well characterized by GPC, NMR, and DSC and all the observations indicated a high efficiency of intra-macromolecular cyclization via Glaser coupling reaction. The critical micelle concentrations of the obtained amphiphilic copolymers were determined by fluorescence probe technique and the morphologies of the formed micelles were investigated by TEM.

Application of named reactions in polymer synthesis

“…Group transfer polymerization (GTP) [4], living anionic and cationic ring opening polymerization [5], living carbocationic polymerization [6], ring-opening metathesis polymerization (ROMP) [7], and controlled/"living" radical polymerization (CRP) [8] techniques are currently known for the precise synthesis of macromolecular architectures with defined molecular weights and end-groups. Although named reactions play an important role in the syntheses of monomers [9,10] and many named reactions such as the Glaser coupling reaction [11,12] and Williamson reaction [13] have been applied for post-polymerization modifications, only a few of them have been introduced to construct the main chain.…”

Design and Synthesis of a Cyclic Double-Grafted Polymer Using Active Ester Chemistry and Click Chemistry via A “Grafting onto” Method

“…Cyclic-grafted polymers consisting of one cyclic backbone and various side chains, as one kind of grafted polymers, have potential applications in biomaterials [ 32 , 33 , 34 ]. There are three main categories for producing cyclic-grafted polymers: (1) “grafting through” approach, the polymerization of cyclic-macromonomers [ 35 ]; (2) “grafting from” approach, the growth of side chains from a cyclic-macroinitiator backbone [ 36 , 37 , 38 , 39 , 40 , 41 , 42 ]; (3) “grafting onto” approach, the addition of ready-made polymeric chains to a cyclic backbone by high-effective chemical reactions or supramolecular assembly, such as esterification reaction [ 43 ], click chemistry [ 44 , 45 , 46 , 47 , 48 ], active ester chemistry [ 49 , 50 ], Suzuki coupling reaction [ 51 ] and metallo-supramolecular interactions [ 52 ]. In the “grafting onto” approach, cyclic backbone and grafting chains can be independently synthesized and characterized.…”

One-pot synthesis of hyperstar polymers via sequential ATRP of inimers and functional monomers in aqueous dispersed media

“…[14][15][16][17] In general, core-shell structured hyperstar polymers are commonly prepared via one of the two well-documented strategies: "grafting from" and "grafting onto". The "grafting from" method applies a terminal-functionalized hyperbranched polymer as a core macroinitiator (MI) for the polymerization of monovinyl monomers using various controlled/"living" polymerization techniques, including atom transfer radical polymerization (ATRP), 15,[18][19][20][21][22][23][24][25][26][27][28] nitroxide-mediated polymerization (NMP), 1,29 reversible addition-fragmentation chain transfer (RAFT) 16,[30][31][32] polymerization, and anionic ring-opening polymerization (ROP). 13,[33][34][35][36] The "grafting onto" method utilizes efficient coupling reactions to tether a chain-end functionalized linear arm onto the terminal-functionalized hyperbranched polymer.…”