Polymerization Of Ionic Liquid Monomers Research Articles

ZIF-8/styrene-IL polymerization hollow fiber membrane for improved CO2/N2 separation

Compared to supported ionic liquid membranes, poly(ionic liquid) membranes are synthesized by the polymerization of ionic liquid monomers to develop polymeric backbone to improve its membrane stability for gas separation process. However, the resulting dense membrane structure induced the lower gas permeance of the poly(ionic liquid) membranes. To overcome this limitation, in this study, ZIF-8, possessing the property of molecular sieves, was added to poly(styrene-ionic liquid) hollow fiber membranes (p(SIL) HFMs), providing a transport pathway. SIL monomers with different lengths of alkyl chain were polymerized and integrated with ZIF-8 fillers to synthesize ZIF-8/poly(ionic liquid) mixed matrix hollow fiber membranes (ZIF-8/p(SIL) MMHFMs). When the chain length of SIL monomers was increased, the CO2 permeance of p(SIL) HFMs increased from 3.6 to 4.6 GPU, while CO2/N2 selectivity decreased from 29 to 23. Additionally, the CO2 permeance of ZIF-8/p(SIL) MMHFMs was enhanced by 33% compared to that of p(SIL) HFMs. However, chain rigidification phenomenon was observed which cause the ZIF-8/p(SIL) MMHFMs showed the decreasing CO2 permeance when the ZIF-8 content was increased. The best separation performance of ZIF-8/p(SIL) MMHFMs was obtained with 0.5 wt% ZIF-8 addition, which exhibited a CO2 permeance and CO2/N2 selectivity of 6 GPU and 30. Therefore, adding ZIF-8 into p(SIL) HFMs to form the ZIF-8/p(SIL) MMHFMs is beneficial to enhance the CO2 permeance of membranes because of the characteristic of the pore size of 3.4 Å and transport pathway provided by ZIF-8 fillers.

Enhancing Electroresponsive Electrorheological Effect and Temperature Dependence of Poly(ionic liquid) Particles by Hard Core Confinement.

Monodisperse core-shell-structured SiO2@poly(ionic liquid) (SiO2@PIL) particles are prepared by the polymerization of ionic liquid monomer on the surface of methacryloxypropyltrimethoxysilane-modified SiO2 particles. The electroresponsive electrorheological (ER) effect of SiO2@PIL particles when dispersed in insulating carrier liquid is investigated and compared with that of pure poly(ionic liquid) (PIL) particles based on temperature-modulated rheology under electric fields. It is demonstrated that hard SiO2 core not only enhances the ER effect of PIL particles but also improves the temperature dependence of ER effect. By dielectric spectroscopy analysis, the mechanism behind the property enhancement was discussed. It indicates that the hard SiO2 core can not only increase the interfacial polarization strength of SiO2@PIL particles by core-shell architecture but also restrain the segment relaxation or softening of the PIL shell and influence the ion dynamics above the calorimetric glass transition of PILs by the so called "substrate confinement effect", and this should be responsible for the enhanced electroresponsive ER effect and temperature stability of the SiO2@PIL particles.

Polymerization of 1‐(2‐Propynyl)‐3‐methylimidazolium Bromide using Cyclometalated Pd(II) Catalysts and Study of the Interaction of Ensuing Oligomer with BSA

AbstractTwo novel cyclometalated binuclear chloro‐bridged palladium based catalysts, {(PdClL1)2} (1) and {(PdClL2)2} (2) have been synthesized by reacting PdCl2 with 4‐nitro‐(benzylidene‐(4‐tert‐butyl‐phenyl)‐amine (L1) and 4‐methylester‐(benzylidene‐(4‐tert‐butyl‐phenyl)‐amine (L2), respectively. These have been characterized by elemental analyses, spectroscopic studies (IR, 1H, 13C NMR, ESI‐MS), and their structures have been authenticated by X‐ray single crystal analyses. Polymerization of ionic liquid monomer using these catalysts has been investigated. 1 exhibited best catalytic activity and each catalyst afforded both conducting and fluorescent oligomers and high molecular weight polymers. Resulting oligomers and polymers have been characterized by spectroscopic and conductivity, GPC, SEM‐EDAX, PXRD studies. Oligomers are fluorescent and their emission intensity enhances upon interaction with anions. Binding behaviour of oligomers has been examined with BSA. Quenching of the intrinsic fluorescence of BSA in presence of oligomers have been studied by steady state, synchronous, and 3D fluorescence spectroscopy and changes in secondary structure quantified by CD spectroscopy.

Graphene and poly(ionic liquid) modified polyurethane sponges with enhanced flame‐retardant properties

ABSTRACTGraphene (Gr) and poly(ionic liquid) (PIL) modified polyurethane (PU) sponges with enhanced flame‐retardant properties were prepared by the direct dip coating of Gr and ionic liquid (IL) monomers onto a PU sponge followed by the polymerization of IL monomers under thermal initiation. With a content of 1.5% Gr in IL, the limiting oxygen index (LOI) of PU–PIL–Gr was 26.1%, whereas the neat PU sponge showed an LOI of only 17.9%. The horizontal flame test results indicate that PIL–Gr prevented horizontal flame spread and eliminated melt dripping. Compared with that of the neat PU sponge, the peak heat release rate of PU–PIL–Gr decreased about 22.0%. These improvements on flame retardancy might have been due to a hybrid flame retardant originating from Gr (which acted as carbon source) and PIL (which contained the flame‐retardant elements) in the PU sponge and the formation of protective layers, which isolated the oxygen and heat more effectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45477.

In situ thermal polymerization of an ionic liquid monomer for quasi‐solid‐state dye‐sensitized solar cells

ABSTRACTIn situ thermal polymerization of a model ionic liquid monomer and ionic liquids mixture to form gel electrolytes is developed for quasi‐solid‐state dye‐sensitized solar cells (Q‐DSSCs). The chemical structures and thermal property of the monomers and polymer are investigated in detail. The effect of iodine concentration on the conductivity and triiodide diffusion of the gel electrolytes is also investigated in detail. The conductivity and triiodide diffusion of the gel electrolytes increase with the increasing I2 concentration, while excessive I2 contents will decrease the electrical performances. Based on the in situ thermal polymeric gel electrolytes for Q‐DSSCs, highest power conversion efficiency of 5.01% has been obtained. The superior long‐term stability of fabricated DSSCs indicates that the cells based on in situ thermal polymeric gel electrolytes can overcome the drawbacks of the volatile liquid electrolyte. These results offer us a feasible method to explore new gel electrolytes for high‐performance Q‐DSSCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42802.

Development of a molecular separation membrane for efficient separation of low-molecular-weight organics and salts

A positively charged nanomaterial was prepared adopting the graft polymerization of ionic liquid monomers on halloysite nanotubes (HNTs) via reverse atom transfer radical polymerization (RATRP). A novel and facile organic–inorganic hybrid molecular separation membrane was then fabricated by the incorporation of modified HNTs via phase inversion method. This hybrid membrane was investigated in terms of morphology structure, hydrophilicity, thermal, mechanical and electrical properties, and separation performances. The results revealed that the hybrid membranes represented thickened and loosened skin layer, enhanced surface hydrophilicity and water flux, as well as good thermal and mechanical properties. Most importantly, the hybrid membranes showed stabilized rejection for Reactive Black 5 (above 90%) and Reactive Red 49 (80%–90%), whereas the rejection for sorts of salts declined to below 10% indicating a potential molecular separation characteristic for dye desalination.

Atom transfer radical polymerization of ionic liquid monomer: The influence of salt/counterion on polymerization

Understanding the influence of salt/counterion on atom transfer radical polymerization (ATRP) is important to optimize the conditions for ATRP of ionic monomers, such as ionic liquid monomer. This article reports the results of a systematical investigation of the variables associated with ATRP in the presence of different types and amounts of salts, solvents, ligands, and monomers. A series of control ATRP experiments were conducted under various polymerization conditions. The kinetics of the polymerizations, the molecular weight, and molecular weight distribution of the formed polymers were studied by nuclear magnetic resonance and gel permeation chromatography. The results indicated that all of the studied variables influenced the ATRP process to different degrees. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2175–2184

Preparation of Submicrometer-Sized Quaternary Ammonium-Based Poly(ionic liquid) Particles via Emulsion Polymerization and Switchable Responsiveness of Emulsion Film

Emulsion polymerization of ionic liquid monomer [2-(methacryloyloxy)ethyl]trimethylammonium bis(trifluoromethanesulfonyl)amide ([MTMA][TFSA]) was performed. In the presence of potassium persulfate and sodium dodecyl sulfate as the ionic initiator and emulsifier, respectively, the system was colloidally unstable and coagulated, owing to anion exchange between the ionic liquid monomer and ionic emulsifier. When a nonionic initiator and emulsifier were used (2,2'-azobis 2-methyl-[1,1-bis(hydroxymethyl)-2-hydroxyethylpropionamide]; VA-080, polyoxyethylenesorbitan monooleate; Tween 80, respectively), a stable emulsion was obtained without coagulation, and the zeta potential of the prepared particles exhibited a high positive charge. Utilizing this surface charge, poly([MTMA][TFSA]) (PIL) particles were then successfully prepared via emulsifier-free emulsion polymerization without an ionic initiator. Moreover, the contact angle of water on the PIL emulsion film (emulsifier-free emulsion polymerization) was found to be ∼70° (static measurement), indicating that the surface of the PIL film was relatively hydrophobic. The retreating contact angle (∼28°) also indicated water wettability. However, when water was dropped on the PIL film just after the water already on the surface had completely retreated, the PIL film was instantaneously hydrophobic again. This result suggests that responsiveness of the PIL emulsion film was switchable between hydrophobic (in air) and hydrophilic (in water).

Cross-linked basic nanogel; robust heterogeneous organocalayst

A novel basic poly(ionic liquid) (PIL) was synthesized by miniemulsion polymerization of ionic liquid monomer 1-ethyl-3-vinylimidazolium bromide [EVim][Br] which was cross-linked by ionic liquid cross-linker 1,4-butanediyl-3,3′-bis-l-vinylimidazolium dibromide (BVD). Exchange of bromide anions in PIL nanogel with hydroxide, produced a supported basic ionic liquid catalyst. The catalytic performances of PIL nanogel with a size of about 200nm was evaluated in the synthesis of 4H-benzo[b]pyrans by multi-component reaction in water. The present protocol represents a simple, ecologically safe and cost-effective route to synthesize 4H-benzo[b]pyrans with high products yield.

Extraordinary aspects of bromo-functionalized multi-walled carbon nanotubes as initiator for polymerization of ionic liquid monomers

Two ionic liquid monomers, 1-(2-acryloyloxy-ethyl)-3-methyl-imidazol-1-ium iodide (AMImI) and 1-(2-acryloyloxy-ethyl)-3-methyl-benzoimidazol-1-ium iodide (AMBImI), were synthesized and polymerized through atom transfer radical polymerization (ATRP). Poly(AMImI)-grafted multi-walled carbon nanotubes (denoted as MWCNT-poly(AMImI)) could also be fabricated through “grafting from” method of ATRP using bromo-functionalized MWCNT (denoted as MWCNT–Br) as initiator but MWCNT-poly(AMBImI) could not. Based on the thermogravimetric analysis and high resolution transmission electron microscopy, AMBImI monomer has encapsulated the MWCNT–Br probably through the π-π and cation-π interactions invalidating the initiation capability of MWCNT–Br. Besides, by mixing AMBImI with MWCNT–Br directly at room temperature, the MWCNT–Br was coated with a thin layer of AMBImI, whereas MWCNT–Br could not physisorb AMImI. Both MWCNT-poly(AMImI) and AMBImI-encapsulated MWCNT were dispersed well in 1-methyl-3-propylimidazolium iodide ionic liquid.

Poly(N-heterocyclic-carbene)s and their CO2 Adducts as Recyclable Polymer-Supported Organocatalysts for Benzoin Condensation and Transesterification Reactions

The synthesis of poly(N-heterocyclic carbene)s, denoted poly(NHC)s, and of their poly(NHC−CO2) adducts for a use in organocatalysis is described. Poly(NHC)s were readily obtained in a three-step sequence of reactions, involving i) the free-radical polymerization of ionic liquid monomers, that is, 1-vinyl-3-alkylimidazolium-type monomers with bromide (Br−) as counteranion, followed by ii) anion exchange of Br− for bis(trifluoromethanesulfonyl)imide (−NTf2), of the poly(1-vinyl-3-alkylimidazolium bromide) precursors, affording poly(1-vinyl-3-alkylimidazolium bis(trifluoromethanesulfonyl)imide) derivatives, and iii) deprotonation of the latter polymeric ionic liquids with a strong base. Carbon dioxide (CO2) was found to reversibly react with poly(NHC)s forming relatively air-stable and thermolabile poly(NHC−CO2) adducts. Both poly(NHC)s and their poly(NHC−CO2) adducts were used as polymer-supported organic catalysts and precatalysts, respectively, in transesterification and benzoin condensation reactions under homogeneous conditions. Both types of polymer-supported NHCs were recycled and used several times, but the manipulation of poly(NHC)s −like their molecular NHC analogues- was more complicated owing to their air and moisture sensitivity. In this regard, zwitterionic poly(NHC−CO2) adducts like their molecular NHC−CO2 analogues could be easier manipulated than their bare poly(NHC) counterparts, providing good to excellent yields even after several organocatalytic cycles, in particular toward the transesterification reaction.

Poly(ionic liquid) Latexes Prepared by Dispersion Polymerization of Ionic Liquid Monomers

In this contribution, we report the facile preparation of vinylimidazolium-typed poly(ionic liquid) (PIL) latexes and nanoparticles via dispersion polymerization of ionic liquid monomers in aqueous solutions. A homologous series of vinylimidazolium-typed ionic liquid monomers with different alkyl tail length (C8−C18) were synthesized via quaternization of 1-vinylimidazole with corresponding n-alkyl bromides. Dispersion polymerization of these monomers was conducted at a monomer concentration of 50 g/L in aqueous solution at 70 °C without addition of further stabilizers. For ionic liquid monomers with sufficiently long alkyl chains (≥C12), PILs nanoparticles of 20−40 nm in diameter were found, which were self-stabilizing in aqueous media. In the same procedure, preparation of cross-linked PIL nanoparticles was performed in the presence of 10 mol % of divinylimidazolium-based cross-linker. The as-synthesized cross-linked PIL nanoparticles could be transferred into organic solvents, such as polar DMF, and no...