- Water swelling, brine soluble imidazole based zwitterionic polymers-synthesis and study of reversible UCST behaviour and gel-sol transitions
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New vinylbenzene substituted imidazole based zwitterionic polymers with unique characteristics like swelling in water and solubility in concentrated brine solution in which they exhibited a reversible upper critical solution temperature (UCST) and gel-sol transitions are reported herein.
- Vasantha, Vivek Arjunan,Jana, Satyasankar,Parthiban, Anbanandam,Vancso, Julius G.
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- Synthesis of imidazolium ABA triblock copolymers for electromechanical transducers
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Nitroxide-mediated polymerization enabled the synthesis of cationic, imidazolium-containing triblock copolymers as a membrane for an electromechanical transducer. Nitroxide-mediated polymerization afforded poly(styrene-b-[1-ethyl-3-(4-vinylbenzyl)imidazolium bis(trifluoromethane sulfonyl)imide)]-b-styrene) in a controlled fashion as confirmed using aqueous size exclusion chromatography and 1H NMR spectroscopy. Dynamic mechanical analysis revealed a modulus of approximately 100 MPa for the triblock copolymer at 23 °C, which was suitable for fabrication of an electromechanical actuator. Evaluation of electromechanical actuators revealed device curvatures over twice the curvatures for Nafion in both the presence and absence of a conductive network composite. Addition of the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethane sulfonate selectively reduced the glass transition temperature (Tg) of the central block and increased overall ionic conductivity. Normalizing temperature with the central block Tg caused the ionic conductivity for the IL-incorporated polymers to collapse onto a single curve, which was an order of magnitude higher than the block copolymer in the absence of added IL.
- Green, Matthew D.,Wang, Dong,Hemp, Sean T.,Choi, Jae-Hong,Winey, Karen I.,Heflin, James R.,Long, Timothy E.
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- Rose Bengal Immobilized on Supported Ionic-Liquid-like Phases: An Efficient Photocatalyst for Batch and Flow Processes
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The catalytic activity of Rose Bengal (RB) immobilized on supported ionic liquid (IL)-like phases was evaluated as a polymer-supported photocatalyst. In these systems, the polymer was designed to play a pivotal role. The polymeric backbone adequately modi
- Valverde, David,Porcar, Raul,Izquierdo, Diana,Burguete, M. Isabel,Garcia-Verdugo, Eduardo,Luis, Santiago V.
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p. 3996 - 4004
(2019/08/01)
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- Chemical Tuning of Zwitterionic Ionic Liquids for Variable Thermophysical Behaviours, Nanostructured Aggregates and Dual-Stimuli Responsiveness
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The design and synthesis of a series of zwitterionic ionic liquids (ZILs) to understand the structure–property relationship towards an increase of the thermal stability, a variation of the glass transition temperature, the shape-tuning of nanostructured aggregates and the tuning of the stimuli responsiveness are demonstrated. The substitution reaction of imidazole with various aliphatic and aromatic bromides followed by the reaction of the corresponding substituted imidazoles with bromoalkyl carboxylic acids of varying spacer length produces the ZILs. In aqueous solution, a ZIL molecule either exist in its ionic liquid (substituted imidazolium bromide) form or its zwitterionic (substituted imidazolium alkyl carboxylate) form with an isoelectric point (pI) depending on the pH value of the solution. Upon changing the pH to near or above the pI, the aqueous ZIL solution undergoes transition from a transparent to a turbid phase due to the formation of insoluble hierarchical nanostructured aggregates of various morphologies, such as spheres, tripods, tetrapods, fern-like, flower-like, dendrites etc. depending on the pH of the solution and the nature of the alkyl/vinyl/aryl substituents. Upon heating the solution a phase transition occurs from turbid to transparent, exhibiting a distinct reversible upper critical solution temperature (UCST)-type cloud point (Tcp). It is observed that the cloud point varies with the nature of the substituent, an increase of the concentration of the ZIL as well as with changes of the pH of the solution.
- Biswas, Yajnaseni,Ghosh, Pratyush,Mandal, Tarun K.
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supporting information
p. 13322 - 13335
(2018/09/10)
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- 1,3-Dipolar cycloaddition reaction of aryl nitrile oxides with alkenes using imidazole and pyridine containing reusable polymeric base catalysts
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Cross-linked poly-1-(4-vinylbenzyl)imidazole and cross-linked poly-4-vinylpyridine have been prepared from respective vinyl monomers using different quantities of divinylbenzene as a cross-linker by radical polymerization. The polymeric bases were charact
- Korgavkar, Nilesh N.,Samant, Shriniwas D.
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supporting information
p. 387 - 394
(2018/02/06)
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- Sponge-like quaternary ammonium-based poly(ionic liquid)s for high CO2 capture and efficient cycloaddition under mild conditions
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Mesoporous poly(ionic liquid)s (MPILs) are promising candidates for CO2 capture and CO2 conversion; however, no quaternary ammonium-based MPIL has been reported for cycloaddition of CO2 to epoxides. Herein, a series of nov
- Xie, Yaqiang,Sun, Qing,Fu, Yawen,Song, Lei,Liang, Jun,Xu, Xun,Wang, Hongtao,Li, Jianhui,Tu, Song,Lu, Xin,Li, Jun
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supporting information
p. 25594 - 25600
(2017/12/26)
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- N-heterocyclic carbene coordinated heterogeneous Pd nanoparticles as catalysts for suzuki-miyaura coupling
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Palladium nanoparticle (Pd NP) catalysts immobilized in a polymer with an N-heterocyclic carbene (NHC) moiety (PICBNHC-Pd) have been developed, wherein the NHC moiety plays dual roles as a crosslinker and a ligand to activate the Pd NPs. The presence of both Pd NPs and NHC was confirmed by STEM/EDS and SR-MAS NMR analyses, respectively. This PICB-NHC-Pd catalyst showed excellent activity in the Suzuki-Miyaura coupling reaction without leaching of Pd. Excellent results were obtained in gram-scale synthesis, and catalyst recovery/reuse experiments were completed without loss of catalyst activity.
- Min, Hyemin,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 837 - 839
(2016/07/16)
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- Copolymer-incarcerated nickel nanoparticles with N-heterocyclic carbene precursors as active cross-linking agents for Corriu-Kumada-Tamao reaction
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We have developed heterogeneous polymer-incarcerated nickel nanoparticles (NPs), which catalyze cross-coupling reactions. The matrix structure of these catalysts incorporates both N-heterocyclic carbenes (NHCs) as ligands and Ni-NPs, thanks to a new design of cross-linking agents in polymer supports. These embedded NHCs were detected by field gradient swollen-resin magic angle spinning NMR analysis. They were successfully applied to Corriu-Kumada-Tamao reactions with a broad substrate scope including functional group tolerance, and the catalyst could be recovered and reused several times without loss of activity.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 10602 - 10605
(2013/08/23)
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