scholarly journals Doubly Dynamic Hydrogel Formed by Combining Boronate Ester and Acylhydrazone Bonds

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 487
Author(s):  
Yusheng Liu ◽  
Yigang Liu ◽  
Qiuxia Wang ◽  
Yugui Han ◽  
Hao Chen ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Solid Content ◽  
Self Healing ◽  
Covalent Bonds ◽  
Boronate Ester ◽  
Isopropyl Acrylamide ◽  
Reversible Addition ◽  
The Difference

The incorporation of double dynamic bonds into hydrogels provides an effective strategy to engineer their performance on demand. Herein, novel hydrogels were PREPARED by combining two kinetically distinct dynamic covalent bonds, boronate ester and acylhydrazone bonds, and the synergistic properties of the hydrogels were studied comprehensively. The functional diblock copolymers P(N-isopropyl acrylamide-co-N-acryloyl-3-aminophenylboronic acid)-b-(N-isopropyl acrylamide-co-diacetone acrylamide) (PAD) were prepared via reversible addition−fragmentation chain transfer (RAFT) polymerization. The hydrogel was constructed by exploiting dynamic reaction of phenyboronic acid moieties with polyvinyl alcohol (PVA) and ketone moieties with adipic dihydrazide (ADH) without any catalyst. The active boronate ester linkage endows the hydrogel with fast gelation kinetics and self-healing ability, and the stable acylhydrazone linkage can enhance the mechanical property of the hydrogel. The difference in kinetics endows that the contribution of each linkage to mechanical strength of the hydrogel can be accurately estimated. Moreover, the mechanical property of the hydrogel can be readily engineered by changing the composition and solid content, as well as by controlling the formation or dissociation of the dynamic linkages. Thus, we provide a promising strategy to design and prepare multi-responsive hydrogels with tunable properties.

Self-Healing Hydrophobic POSS-functionalized Fluorinated Copolymer via RAFT Polymerization and dynamic Diels-Alder Reaction

2021 ◽  
Author(s):  
Siva Ponnupandian ◽  
Prantik Mondal ◽  
Thomas Becker ◽  
Richard Hoogenboom ◽  
Andrew B Lowe ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Alder Reaction ◽  
Diels Alder ◽  
Self Healing ◽  
Diels Alder Reaction ◽  
Reversible Addition

This investigation reports the preparation of a tailor-made copolymer of furfuryl methacrylate (FMA) and trifluoroethyl methacrylate (TFEMA) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The furfuryl groups of the copolymer...

scholarly journals Synthesis of Poly(3-vinylpyridine)-Block-Polystyrene Diblock Copolymers via Surfactant-Free RAFT Emulsion Polymerization

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3145 ◽  
Author(s):  
Katharina Nieswandt ◽  
Prokopios Georgopanos ◽  
Clarissa Abetz ◽  
Volkan Filiz ◽  
Volker Abetz
Keyword(s):  
Emulsion Polymerization ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Free Water ◽  
Monomer Conversion ◽  
Molecular Weights ◽  
Reversible Addition

In this work, we present a novel synthetic route to diblock copolymers based on styrene and 3-vinylpyridine monomers. Surfactant-free water-based reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization of styrene in the presence of the macroRAFT agent poly(3-vinylpyridine) (P3VP) is used to synthesize diblock copolymers with molecular weights of around 60 kDa. The proposed mechanism for the poly(3-vinylpyridine)-block-poly(styrene) (P3VP-b-PS) synthesis is the polymerization-induced self-assembly (PISA) which involves the in situ formation of well-defined micellar nanoscale objects consisting of a PS core and a stabilizing P3VP macroRAFT agent corona. The presented approach shows a well-controlled RAFT polymerization, allowing for the synthesis of diblock copolymers with high monomer conversion. The obtained diblock copolymers display microphase-separated structures according to their composition.

Synthesis, self-assembly and self-healing properties of organic–inorganic ABA triblock copolymers with poly(POSS acrylate) endblocks

2019 ◽  
Vol 10 (19) ◽  
pp. 2424-2435 ◽  
Author(s):  
Bingjie Zhao ◽  
Sen Xu ◽  
Sixun Zheng
Keyword(s):  
Self Assembly ◽  
Triblock Copolymer ◽  
Chain Transfer ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Self Healing ◽  
Reversible Addition ◽  
Aba Triblock Copolymer

A novel organic–inorganic ABA triblock copolymer with a poly(acrylate amide) (PAA) midblock and poly(POSS acrylate) [P(POSS)] endblocks was synthesized via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization.

Synthesis and Solution-state Assembly or Bulk State Thiol-ene Crosslinking of Pyrrolidinone- and Alkene-functionalized Amphiphilic Block Fluorocopolymers: From Functional Nanoparticles to Anti-fouling Coatings

2010 ◽  
Vol 63 (8) ◽  
pp. 1159 ◽  
Author(s):  
Jun Ma ◽  
Jeremy W. Bartels ◽  
Zhou Li ◽  
Ke Zhang ◽  
Chong Cheng ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Building Blocks ◽  
Ene Reactions ◽  
Reversible Addition ◽  
Complex Building ◽  
Crosslinked Networks ◽  
Amphiphilic Diblock Copolymers ◽  
Synthetic Methodologies

With an ever increasing interest in the combined functionality and versatility of materials, increasing demands are placed on synthetic methodologies by which to produce such materials. This work demonstrates the preparation of block copolymers having fluorocarbon content, pyrrolidinone units, and alkene groups as complex building blocks for the assembly of discrete nanoparticles in solution and, alternatively, transformation into sophisticated crosslinked networks. Reversible addition–fragmentation chain transfer (RAFT) polymerization is a facile tool for the synthesis of well-defined polymers containing imbedded side-chain functionalities. In this work, the synthesis of well-defined multifunctional fluorinated polymers bearing pendant pyrrolidinone groups, and block copolymers bearing both pyrrolidinone and alkenyl groups on different segments was achieved, by using RAFT polymerizations of unique bifunctional monomers. Upon micellization, the amphiphilic diblock copolymers were transformed into regioselectively-functionalized nanoparticles. Further transformations of pyrrolidinone- and alkene-dual functionalized-block copolymers into complex amphiphilic networks were accomplished by highly efficient UV-induced thiol-ene reactions. Whether as discrete nanoparticles or nanoscopically-segregated crosslinked networks, these materials have great potential for several diverse technologies, including as anti-fouling materials.

scholarly journals RAFT Emulsion Polymerization of Styrene Using a Poly((N,N-dimethyl acrylamide)-co-(N-isopropyl acrylamide)) mCTA: Synthesis and Thermosensitivity

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 62
Author(s):  
Katharina Nieswandt ◽  
Prokopios Georgopanos ◽  
Martin Held ◽  
Evgeni Sperling ◽  
Volker Abetz
Keyword(s):  
Emulsion Polymerization ◽  
Diblock Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Molar Fraction ◽  
Solution Temperature ◽  
Hydrophobic Core ◽  
Spherical Micelle ◽  
Thermoresponsive Polymers ◽  
Isopropyl Acrylamide

Thermoresponsive poly((N,N-dimethyl acrylamide)-co-(N-isopropyl acrylamide)) (P(DMA-co-NIPAM)) copolymers were synthesized via reversible addition−fragmentation chain transfer (RAFT) polymerization. The monomer reactivity ratios were determined by the Kelen–Tüdős method to be rNIPAM = 0.83 and rDMA = 1.10. The thermoresponsive properties of these copo-lymers with varying molecular weights were characterized by visual turbidimetry and dynamic light scattering (DLS). The copolymers showed a lower critical solution temperature (LCST) in water with a dependence on the molar fraction of DMA in the copolymer. Chaotropic and kosmotropic salt anions of the Hofmeister series, known to affect the LCST of thermoresponsive polymers, were used as additives in the aqueous copolymer solutions and their influence on the LCST was demonstrated. Further on, in order to investigate the thermoresponsive behavior of P(DMA-co-NIPAM) in a confined state, P(DMA-co-NIPAM)-b-PS diblock copolymers were prepared via polymerization induced self-assembly (PISA) through surfactant-free RAFT mediated emulsion polymerization of styrene using P(DMA-co-NIPAM) as the macromolecular chain transfer agent (mCTA) of the polymerization. As confirmed by cryogenic transmission electron microscopy (cryoTEM), this approach yielded stabilized spherical micelles in aqueous dispersions where the PS block formed the hydrophobic core and the P(DMA-co-NIPAM) block formed the hydrophilic corona of the spherical micelle. The temperature-dependent behavior of the LCST-type diblock copolymers was further studied by examining the collapse of the P(DMA-co-NIPAM) minor block of the P(DMA-co-NIPAM)-b-PS diblock copolymers as a function of temperature in aqueous solution. The nanospheres were found to be thermosensitive by changing their hydrodynamic radii almost linearly as a function of temperature between 25 °C and 45 °C. The addition of kosmotropic salt anions, as a potentially useful tuning feature of micellar assemblies, was found to increase the hydrodynamic radius of the micelles and resulted in a faster collapse of the micelle corona upon heating.

RAFT Polymer End-Group Modification and Chain Coupling/Conjugation Via Disulfide Bonds

2009 ◽  
Vol 62 (8) ◽  
pp. 830 ◽  
Author(s):  
Cyrille Boyer ◽  
Jingquan Liu ◽  
Volga Bulmus ◽  
Thomas P. Davis
Keyword(s):  
Disulfide Bonds ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Gel Permeation Chromatography ◽  
Reversible Addition ◽  
Group Modification ◽  
End Groups ◽  
End Group Modification ◽  
High Yields ◽  
End Group

End-group modification of polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization was accomplished by the conversion of trithiocarbonate or dithioester end-groups into a pyridyl disulfide (PDS) functionality. Several different polymers, such as poly(methyl methacrylate), polystyrene, poly(oligoethylene glycol-acrylate), poly(hydroxypropylacrylamide), and poly(N-isopropylacrylamide) were prepared by RAFT polymerization, and subjected to aminolysis in the presence of 2,2′-dithiodipyridine to yield thiol-terminated polymers with yields in the range 65–90% dependent on the polymer structure. Furthermore, this PDS end-group was utilized to generate higher-order architectures, such as diblock copolymers with high yields and selectively. In addition, the PDS end-groups were used for the bioconjugation of different biomolecules, such as oligonucleotides, carbohydrates, and peptides. The successful modification of well-defined polymers was confirmed by a combination of UV-vis, NMR spectroscopy, and gel permeation chromatography.

Engineering of pH-triggered nanoplatforms based on novel poly(2-methyl-2-oxazoline)-b-poly[2-(diisopropylamino)ethyl methacrylate] diblock copolymers with tunable morphologies for biomedical applications

2021 ◽  
Author(s):  
Peter Černoch ◽  
Alessandro Jäger ◽  
Zulfia Cernochova ◽  
Vladimir Sincari ◽  
Lindomar Calumby Albuquerque ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Ring Opening ◽  
Biomedical Applications ◽  
Diblock Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Amphiphilic Block Copolymers ◽  
Synthetic Approach ◽  
Ethyl Methacrylate ◽  
Reversible Addition

A two-step synthetic approach via the combination of living cationic ring-opening (CROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization techniques was used to produce novel amphiphilic block copolymers based on...

scholarly journals Lanthanoids Goes Healing: Lanthanoidic Metallopolymers and Their Scratch Closure Behavior

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 838
Author(s):  
Stefan Götz ◽  
Stefan Zechel ◽  
Martin D. Hager ◽  
Ulrich S. Schubert
Keyword(s):  
Metal Complexes ◽  
Raft Polymerization ◽  
Polymer Chains ◽  
Titration Calorimetry ◽  
Self Healing ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
3D Microscopy ◽  
Reversible Addition ◽  
Supramolecular Networks

Metallopolymers represent an interesting combination of inorganic metal complexes and polymers resulting in a variety of outstanding properties and applications. One field of interest are stimuli-responsive materials and, in particular, self-healing polymers. These systems could be achieved by the incorporation of terpyridine–lanthanoid complexes of Eu (III), Tb (III), and Dy (III) in the side chains of well-defined copolymers, which were prepared applying the reversible addition fragmentation chain-transfer (RAFT)-polymerization technique. The metal complexes crosslink the polymer chains in order to form reversible supramolecular networks. These dynamics enable the self-healing behavior. The information on composition, reversibility, and stability of the complexes was obtained by isothermal titration calorimetry (ITC). Moreover, self-healing experiments were performed by using 3D-microscopy and indentation.

scholarly journals Synthesis and self-assembling amphiphilic diblock-copolymers of (2,3,4,5,6)-pentafluorostyrene

2019 ◽  
Vol 484 (4) ◽  
pp. 431-435
Author(s):  
K. E. Chekurov ◽  
A. I. Barabanova ◽  
I. V. Blagodatskikh ◽  
B. V. Lokshin ◽  
A. S. Peregudov ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Microphase Separation ◽  
Raft Polymerization ◽  
Contact Angles ◽  
Hydroxyethyl Methacrylate ◽  
Water Contact ◽  
Self Assembling ◽  
Reversible Addition ◽  
Amphiphilic Diblock Copolymers ◽  
Large Water

Amphiphilic diblock-copolymers (DC) of (2,3,4,5,6)-pentafluorostyrene and 2-hydroxyethyl methacrylate were prepared for the first time by two-step reversible addition–fragmentation chain transfer (RAFT) polymerization. The morphology of films of diblock-copolymers that have a composition close to equimolar was studied by transmission electron microscopy. The observed microphase separation and formation of spherical nanodomains is not typical for equimolar diblock-copolymers and seems to result from hydrogen bonding between the hydroxyl and carbonyl groups (OH···OH and C=O···HO) in poly(2-hydroxyethyl methacrylate) blocks. Obviously, it is the ability of diblock-copolymers to self-organization is the cause of formation of fabric coatings with low surface energy (γ = 11.9 mJ/m2) and relatively large water contact angles (θН2О = 120±6°) and diiodmetane (θCH2I2 = 93±2°).

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