Comparison of Loading Efficiency between Hyperbranched Polymers and Cross‐Linked Nanogels at Various Branching Densities

Graff, Robert W.; Shi, Yi; Wang, Xiaofeng; Gao, Haifeng

doi:10.1002/marc.201500388

Cited by 18 publications

(17 citation statements)

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“…It is also important to note that the leak of deactivator into aqueous phase could also affect the radical–radical termination reaction that cannot be completely avoided in any radical polymerization. The radical coupling reaction between two propagating primary chains produced a tetrafunctional cross‐linkage, so called “X”‐shape cross‐linkage, [ 74 ] from which four chains radiate out. This “X”‐cross‐linkage was not included in the DB calculation, but indeed had influence on the structural compactness of the hyperbranched polymers.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

Cuneo

Shi

Gao

2020

Macro Chemistry & Physics

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Atom transfer radical polymerization (ATRP), as one of the most successful controlled radical polymerization techniques, has been broadly used by polymer chemists and nonspecialists for synthesis of various functional materials, although the use of copper as traditional catalyst often results in undesired color or properties. The first homopolymerization of an initiable monomer, that is, inimer, is reported via metal‐free ATRP using 10‐phenylphenothiazine (Ph‐PTH) as photocatalyst in both solution and microemulsion media. Although polymerizations of inimers in both media can be carried out, only the microemulsion polymerization of methacrylate‐based inimer 1 effectively confines the random bimolecular reaction within each segregated latex and produces hyperbranched polymers with high molecular weight and low polydispersity. Several experimental parameters in the microemulsion polymerization of inimer 1 are subsequently studied, including the Ph‐PTH amount, the solids content of microemulsion, and the light source of irradiation. The results not only provide an effective method to tune the structure and molecular weights of hyperbranched polymers in confined‐space polymerization, but also expand the toolbox of using metal‐free ATRP method for synthesizing highly branched polymers in controlled manner.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

Cuneo

Shi

Gao

2020

Macro Chemistry & Physics

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“…Gao et al. have demonstrated that the loading efficiencies of HBPs were three times larger than that in the cross‐linked nanogel system achieved through copper‐catalyzed click reaction between azido groups in the HBPs or cross‐linked structures and alkynyl‐containing dendron guest molecules . They also used a structurally defined LCHBP grafting star polymer to encapsulate Au 25 (SR) 18 nanoclusters for polymer‐Au nanocomposite catalysis ( Figure ) .…”

Section: Applications Of Lchbpsmentioning

confidence: 99%

“…[11,17,18] Gao et al have demonstrated that the loading efficiencies of HBPs were three times larger than that in the cross-linked nanogel system achieved through copper-catalyzed click reaction between azido groups in the HBPs or cross-linked structures and alkynyl-containing dendron guest molecules. [155] They also used a structurally defined LCHBP grafting star poly mer to encapsulate Au 25 (SR) 18 nanoclusters for polymer-Au nanocomposite catalysis (Figure 26). [105] The LCHBP was synthesized by the developed polymerization in microemulsion of an inimer with a cyclic disulfide-containing methacrylate monomer, and subsequent radiating polymerization for growing arms.…”

Section: Catalyst Carriermentioning

confidence: 99%

Long‐Chain Hyperbranched Polymers: Synthesis, Properties, and Applications

Liu

Tian

2018

Macromol. Rapid Commun.

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By combining the virtues of conventional linear and hyperbranched polymers, long‐chain hyperbranched polymers (LCHBPs) have attracted great attention. Therefore, a comprehensive summary of the research progress of LCHBPs is presented, with a particular focus on their synthetic strategies, unique properties, and potential applications. The synthetic methodologies are rationalized into four main classes according to their construction process or mechanism, namely ABx (x ≥ 2), A2 + Bx (x ≥ 3), AB + ABx (x ≥ 2), and self‐condensing vinyl polymerization. Some of their rheological properties, self‐assembly behavior, and stimuli‐response features are then discussed. Finally, the emergent applications including biomedicine, electrical conductivity, chemical sensing, and catalyst carrier, are outlined. It is anticipated that this review will stimulate more inspiration for advancing the development of this novel kind of LCHBP.

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“…Copper partitioning between the dispersed phase to the continuous phase has been critical to impact the control of ATRP in emulsion systems . Although a highly hydrophobic ligand BPMODA* was used in the present study, the copper complex, especially the Cu(II)/BPMODA* was still possible to exit the dispersed polymer latex, resulting in a slower radical deactivation reaction and longer primary chain length than expected.…”

Section: Resultsmentioning

confidence: 94%

“…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 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Highly Branched Copolymers in Microemulsion

Cuneo

Graff

Gao

2019

Macro Chemistry & Physics

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NMP) [20][21][22][23][24] 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. [4,48] However, all the solution (co)polymerizations have been shown to result in broad molecular weight distributions due to the random bimolecular (monomer-monomer, monomer-polymer, and polymer-polymer) reactions. [48] Meanwhile, biphasic dispersed systems, such as microemulsion [49][50][51] emulsion, and miniemulsion, [52] have long been employed in conventional radical polymerization and were recently applied in RDRP techniques, [50,51,53] exhibiting intriguing compartmentalization effects on regulating polymerization kinetics and polymer structures. Previous work by our group established a one-pot method for SCVP of inimer in microemulsion through Activators Generated by Electron Transfer [54] (AGET) ATRP. The key feature in this method was that micelles functioned as confined space to segregate the polymerization of inimers into each discrete nanoparticle, which effectively regulated the polymer-polymer reaction and defined the dispersity of the hyperbranched polymers based on the uniformity of the latexes. [4] Further investigation verified the versatility of the method by using a variety of inimer species carrying different reactive and degradable groups. [5] The utility of these hyperbranched polymers was expanded to the synthesis of seeded two-step one-pot polymerization and produce core-shell structured branched polymers. [6] Herein, we present the first, to the best of our knowledge, one-pot copolymerization of inimer and monomer in confined space, that is, microemulsion, providing a simple framework for producing branched polymers with varied compositions and branching densities, while retaining the same extent of polymer molecular weight. To explore the suitability of copolymerization of monomers with inimers in AGET ATRP microemulsion, a model system was developed, consisting of a monomer and inimer with similar structures and vinyl reactivity. The ratio of monomer to inimer was varied to alter the structural composition while holding constant all other formulation parameters, Branched PolymersAtom transfer radical copolymerization of monomer and inimer (containing initiating and monomer fragments in one molecule) is carried out in a micro emulsion to produce branched copolymers with similar molecular weights but varied branching densities. The monomer 2-(isobutyryloxy) ethyl methacrlyate (IEM) shares a similar structure as the selected inimer 2-(2-bromoisobutylryloxy) ethyl methacrylate (BIEM) and provides microemulsification with little change of micelle size upon varying the molar ratio of monomer to inimer (γ ) from 2 to 50. The copolymerization of IEM and BIEM in the disc...

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Comparison of Loading Efficiency between Hyperbranched Polymers and Cross‐Linked Nanogels at Various Branching Densities

Cited by 18 publications

References 50 publications

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

Long‐Chain Hyperbranched Polymers: Synthesis, Properties, and Applications

Synthesis of Highly Branched Copolymers in Microemulsion

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