Well-Defined Brush Copolymers with High Grafting Density of Amphiphilic Side Chains by Combination of ROP, ROMP, and ATRP

Abstract

This work reports a facile strategy for the preparation of a novel well-defined brush copolymer with two different grafts distributed on the same unit along the backbone via combination of three controlled polymerization methods, ring-opening polymerization (ROP), ring-opening metathesis polymerization (ROMP), and atom transfer radical polymerization (ATRP) based on the synthesis of the heterotrifunctional inimer, 2-hydroxymethyl-3-(2-bromoisobutyryloxymethyl)-5-norbornene (NBE-OH/Br). ROP of ε-caprolactone initiated by NBE-OH/Br was carried out to generate macroinimer, norbornene-graft-poly(ε-caprolactone)/Br (NBE-g-PCL/ Br). The grafting-through strategy was then employed to construct the polymer backbone, poly(norbornene)graft-poly(ε-caprolactone)/Br (PNBE-g-PCL/Br) via ROMP of the norbornene-terminated macroinimer NBE-g-PCL/Br. Finally, the grafting-from route was used for the synthesis of amphiphilic grafted brush copolymer, poly(norbornene)-graft-poly(ε-caprolactone)/poly(2-(dimethylamino)ethyl methacrylate) (PNBE-g-PCL/PDMAE-MA) by ATRP of 2-(dimethylamino)ethyl methacrylate using bromo-functionalized ROMP product PNBE-g-PCL/Br as macroinitiators, containing one hydrophobic PCL graft and one hydrophilic PDMAEMA graft on each unit of the backbone.

Applications of Orthogonal “Click” Chemistries in the Synthesis of Functional Soft Materials

“…154 ROP of ε-caprolactone (CL) was initiated by 2-hydroxymethyl-3-(2-bromoisobutyrloxymethyl)-5-norbornene (NBE-OH/Br) to generate a norbornene- graft -poly(ε-caprolactone)/Br (NBE- g -PCL) macroinimer (Scheme 18). The “grafting through” strategy was subsequently employed to construct the polymer backbone via ROMP of the norbornene functionality, after which poly((2-dimethylamino)ethyl methacrylate) grafts were grown by a “grafting from approach,” from the backbone by ATRP (Scheme 18).…”

RAFT preparation and the aqueous self-assembly of amphiphilic poly(octadecyl acrylate)- block -poly(polyethylene glycol methyl ether acrylate) copolymers

“…Presently, a variety of well-defined amphiphilic polymers with various architectures have been synthesised by controlled/"living" polymerisation methods, such as atom transfer radical polymerisation (ATRP) [45][46][47], ring-opening polymerisation (ROP) [46,48,49], nitroxide-mediated free radical polymerisation (NMP) [50][51][52], ring-opening metathesis polymerisation (ROMP) [46,53,54] and reversible addition-fragmentation chain transfer (RAFT) polymerisation [55][56][57][58][59][60]. RAFT has been used to prepare brush-type copolymers based on PEG, which selfassemble in water into interesting micelle morphologies [56,57,61].…”

Novel Dual-Grafted Copolymer Bearing Glassy Polystyrene and Crystalline Poly(Ethylene Oxide) as Side Chains

“…A combination of two chemically distinct domains that do not enclose each other endows the polymer with unique physical properties and potential applications in giant surfactants (1), nanomaterials (16,17), drug encapsulation and delivery (18), and biological systems (19). Such complex copolymer grafts can be obtained through diverse polymerization processes, such as atom transfer radical polymerization (ATRP) (12,(20)(21)(22), nitroxide mediated polymerization (NMP) (1), reversible addition-fragmentation chain transfer (RAFT) (1, 2, 23), or ring opening metathesis polymerization (ROMP) (24). However, the preparation of a well-defined structure and unimodal copolymer is still the preferred strategy.…”