Well-Defined Diblock Macromonomer with a Norbornene Group at Block Junction: Anionic Living Linking Synthesis and Ring-Opening Metathesis Polymerization

We have developed a hierarchical process that combines linear triblock copolymers into concentric globular sub-units through strong chemical bonds and is followed by their supramolecular assembly via weak non-covalent interactions to afford one-dimensionally-assembled, dynamic cylindrical nanostructures. The molecular brush architecture forces triblock copolymers to adopt some intramolecular interactions within confined frameworks and then drives their intermolecular interactions in the mixtures of organic solvent and water. In contrast, the triblock copolymers, when not pre-connected into the molecular brush architectures, organize only into globular assemblies.

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“…ROMP has been widely used to polymerize bulky macromonomers to afford densely-grafted polymers 25-28, 31-34. As shown in the GPC trace (Fig.…”

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confidence: 99%

Dynamic Cylindrical Assembly of Triblock Copolymers by a Hierarchical Process of Covalent and Supramolecular Interactions

et al. 2011

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“…Well‐defined diblock MMs are required for the preparation of DBCs . Therefore, a well‐defined diblock MM, PSt 10 ‐NB‐PEO 45 ( 3 ), was obtained by RAFT polymerization of St in bulk by using 2 as the macro‐RAFT agent.…”

Section: Resultsmentioning

confidence: 99%

“…We are interested in double-brush copolymers (DBCs), a special class of heterografted brush copolymer with each backbone unit carrying two different grafts. [48][49][50] We have reported the synthesis of the first example of well-defined amphiphilic DBCs, which possess both hydrophilic poly(ethylene oxide) (PEO) grafts and hydrophobic polylactide grafts. 49 Relative to the diblock precursor, these amphiphilic DBCs were significantly more effective in stabilizing miniemulsions.…”

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confidence: 99%

Crosslinking-induced morphology change of latex nanoparticles: A study of RAFT-mediated polymerization in aqueous dispersed media using amphiphilic double-brush copolymers as reactive surfactants

Christian-Tabak

Fuan

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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Amphiphilic double-brush copolymers (DBCs) with each graft site quantitatively carrying both a hydrophilic poly(ethylene oxide) (PEO) graft and a hydrophobic polystyrene (PSt) graft are synthesized by sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and ring-opening metathesis polymerization (ROMP). These DBCs are used as both surfactants and polyfunctional RAFT agents in the radical polymerization of St in aqueous dispersed media. Miniemulsions with narrowly dispersed St-based nanodroplets are readily obtained after ultrasonication of the reaction mixtures. Without the presence of crosslinker, chain-extension polymerization of St from the DBCs yields well-defined polymeric latexes with narrow size distributions. However, with the presence of divinylbenzene (DVB) as the crosslinker, vesicular polymeric nanoparticles are formed as the major product. Such crosslinking-induced change in morphology of the resulting latex nanomaterials may be ascribed to the increase of interfacial curvature in the heterophase systems during crosslinking polymerization.

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“…ROMP also has demonstrated a wide functional group tolerance to produce well‐defined bottlebrush block copolymers with MMs carrying heteroatom functional groups through sequential ROMP 43–46. Well‐controlled MMs are needed for well‐defined bottlebrush polymers and they have been synthesized from a variety of techniques, which suppress side reactions of norbornene incorporation, such as reversible addition‐fragmentation chain transfer (RAFT) polymerization,47–49 atom transfer radical polymerization (ATRP),50–52 living anionic polymerization (LAP),53,54 ring‐opening polymerization (ROP),55 and other types of polymerizations 56,57. Thus, a wide library of potential MMs exist to create new bottlebrush block copolymers.…”

Section: Introductionmentioning

confidence: 99%

Cationic Bottlebrush Polymers from Quaternary Ammonium Macromonomers by Grafting‐Through Ring‐Opening Metathesis Polymerization

Senkum

Gramlich

2020

Macro Chemistry & Physics

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Cationic bottlebrush homopolymers are polymerized using a grafting‐through approach by ring‐opening metathesis polymerization (ROMP) to afford well‐defined polymers. Quaternary ammonium macromonomers (MMs) are prepared by quaternizing tertiary amine MMs synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization. The quaternary ammonium MMs undergo ROMP to target molecular weights (Mn = 30 000–100 000 g mol−1) and a low dispersity (Đ = 1.10–1.30). Halide‐ligand exchange between the third generation Grubbs catalyst (G3) and halide counter ions (bromide and iodide ions) of MMs changes the catalyst activity throughout ROMP, causing it to deviate from pseudo‐first order kinetic behavior; however, the polymerization still follows controlled behavior without significant catalyst termination. Increasing steric bulk of the MMs decreases the polymerization rate as well. Amphiphilic block copolymers are synthesized by sequential polymerization of quaternary ammonium MMs and polystyrene (PS) MMs. Using a PS macroinitiator affords block copolymers with lower Đ values as compared to the less active cationic macroinitiator.

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Well-Defined Diblock Macromonomer with a Norbornene Group at Block Junction: Anionic Living Linking Synthesis and Ring-Opening Metathesis Polymerization

Cited by 32 publications

References 39 publications

Dynamic Cylindrical Assembly of Triblock Copolymers by a Hierarchical Process of Covalent and Supramolecular Interactions

Dynamic Cylindrical Assembly of Triblock Copolymers by a Hierarchical Process of Covalent and Supramolecular Interactions

Crosslinking-induced morphology change of latex nanoparticles: A study of RAFT-mediated polymerization in aqueous dispersed media using amphiphilic double-brush copolymers as reactive surfactants

Cationic Bottlebrush Polymers from Quaternary Ammonium Macromonomers by Grafting‐Through Ring‐Opening Metathesis Polymerization

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