Encapsulation Of Ionic Liquids Research Articles

Synergistic ionic liquid encapsulated MIL-101 (Cr) metal-organic frameworks for an innovative adsorption desalination system

The transformations of brackish water into freshwater employing porous materials such as metal-organic frameworks (MOFs) show a great potential for a green environment. But the adsorption-based desalination slows down due to slow water adsorption/desorption rates and inadequate water storage capacity in conventional adsorbents. Therefore, the restructuring of porous MOFs increases water storage and transfer rates. This paper presents a comprehensive investigation on the fabrication of ionic liquid encapsulated MIL-101 (Cr) MOFs (metal-organic frameworks), and its interactions with water for desalination applications. Firstly, the pristine MIL-101 (Cr) is encapsulated with various types/amounts of ionic liquids. Next, these MOFs are characterized via SEM (Scanning electron microscope), FTIR (Fourier transform infrared), XRD (X-ray diffraction), TGA (Thermal gravimetric analysis), N2 adsorption techniques. The water adsorption on these MOFs is performed experimentally for a wide temperature (30–80 °C) and pressure (0 < P/Ps < 0.95) ranges. The effects of the size (or type) as well as the encapsulation ratio of ionic liquids on water adsorption behaviors are conducted. Based on the experimentally proven water adsorption (isotherms and kinetics) data, an AD (adsorption desalination) system is modelled and simulated. Finally, the AD performances in terms of the specific daily water production (SDWP) and performance ratio (PR) are parametrically studied with respect to various regeneration temperature (50–80 °C) and cycle times (100 s–1000 s). It is found that by ionic liquid encapsulation, the water uptakes/offtake rates are expedited up to 48% (for adsorption)/55% (for desorption), respectively. In addition, the water transfer (Δq) improves up to 45% more than the parent MIL-101(Cr) MOFs. Furthermore, the SDWP increases from 38 to 56 m3 of water per tonne of MOFs per day at the regeneration temperature of 70 °C. The simulation results also show that the ionic-liquid-encapsulated MIL-101 (Cr) MOFs generates water (>25 m3 water per tonne of IL-MOFs) at the regeneration temperature of 50 °C and is potential for the next generation desalination applications.

Theoretical study on the capture of toxic gases by ionic liquids encapsulated in assembled belt[14[pyridine

In the current study, self-assembled belt[14]pyridine (BP) encapsulated IL (tetramethylammonium chloride (TMACl)) is theoretically explored to capture greenhouse gases (GHGs) at B3LYP-D3/6-311G(d,p) level of theory. The encapsulation of TMACl in assembled belt[14]pyridine is thermodynamically feasible as revealed through high interaction energy value of −50.7 kcal/mol. Moreover, the results of capturing of gas molecules (SO2, CO2, CO and CH4) show that attractive forces involved in capturing of gases are strong van der Waals forces i.e., London dispersion forces and electrostatic interactions. The synergic effect of self-assembled belts and ionic liquid results in significantly high interaction energy values ranging from −7.88 to −25.92 kcal/mol for capturing of gas molecules. Furthermore, the interaction between BP-TMACl and gas molecules is studied in detail through natural bond orbital (NBO) analysis. NBO results show the charge transfer between the fragments (BP-TMACl and gases) which is further validated through EDD analysis. The charge shifts towards all of the captured gas molecules but the most prominent change in NBO charges is shown by captured SO2. The successful charge transfer indicates better interaction in the designed systems. Additionally, the type and strength of interactions involved in the process of encapsulation is studied through quantum theory of atoms in molecules (QTAIM) and noncovalent interactions (NCI) analysis. NCI analysis clearly shows that gases are captured by BP-TMACl complex through strong van der Waals forces. However, in capturing of SO2, strong electrostatic attractive forces are also involved. The nature of attractive forces is confirmed through QTAIM analysis. Furthermore, the relation between recovery time and desorption energy of captured gas molecules has been studied. The strongest absorption for SO2 results in prolonged recovery time for it (as compared to the other gas molecules). AIMD analysis is performed to find the dynamical stability of assembled-belts before and after loading ionic liquids along with gases to be captured. These results reveal that assembled-belts are suitable for encapsulation of ionic liquids along with capturing of gases. Overall, the best results are shown for SO2 capture. The study intends to deliver valuable information on the important progress in the environmental-remediation field and we hope our work is going to inspire more investigators to provide novel research on such challenging tasks.

Removal of diclofenac from aqueous solution by chitosan-encapsulated Aliquat-336 capsules: Optimization of preparation conditions and adsorption mechanism

To enhance the effectiveness of ionic liquids in water treatment, a novel approach was devised involving the encapsulation of ionic liquids within a chitosan shell. This study focuses on the development and application of chitosan-encapsulated Aliquat-336 capsules (CACs) for the removal of diclofenac (DCF) from aqueous solution. The optimal preparation conditions, as determined through response surface methodology, were as follows: (1) Aliquat-336 content = 13.8%, (2) TPP concentration = 6%, and (3) crosslinking time = 0.5 h. CACs exhibited exceptional adsorption capabilities for DCF across a wide pH range, and the maximum adsorption capacity was 387.2 ± 25.6 mg/g at pH 7 according to the adsorption isotherm results. Adsorption kinetic results showed that the overall adsorption rate of DCF was controlled by liquid film diffusion. Furthermore, the slight antagonism of coexisting anions at low concentrations and significant synergy at high concentrations confirmed the practical suitability of CACs. The characterization of CACs before and after adsorption was analyzed by electron microscopy, pHPZC analysis, Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results demonstrated the successful preparation of CACs and underscored the pivotal role played by the quaternary amine group within Aliquat-336, encapsulated within the CACs, in facilitating the removal of DCF through electrostatic attraction.

Encapsulation of ionic liquid, phosphotungstic acid inside the nanocages of MIL-101(Cr): Effective and reusable catalyst for efficient solvent-free oxidative desulfurization from fuel oil

Oxidative desulfurization from fuel oil is one of the important methods for deep desulfurization. The development of efficient oxidative desulfurization catalysts is crucial for improving the desulfurization performance. Successful encapsulation of phosphotungstic acid (HPW) and ionic liquid (BMImBr) inside the mesoporous cages of MIL-101(Cr) was accomplished through a combination of “bottle around ship” and “ship in bottle” methods. The obtained BMImPW@MIL-101(Cr) composite was characterized by XRD, FTIR, BET, SEM, XPS and ICP methods. Results indicated that the BMImPW@MIL-101(Cr) composites with PW3− loading of 23.1–50.7 wt% were obtained, demonstrating that the “bottle around ship” method is beneficial to make full use of nanocages of MIL-101(Cr) to obtain expected high loading of active PW3−. The BMImPW@MIL-101(Cr) exhibits excellent reusability with no evidence of leaching of active PW3− and BMIm+, and well-preserved structure after successive cycles of regeneration and reuse. The significantly improved stability of BMImPW@MIL-101(Cr) as compared to HPW@MIL-101(Cr) is possibly because the leaching of the active PW3−− sites can be greatly suppressed by forming large size of BMImPW owing to introduction of BMIm+ cation. The BMImPW@MIL-101(Cr) exhibited excellent catalytic activity for solvent free oxidative desulfurization of refractory sulfides. The enhanced oxidative desulfurization activity as compared to HPW@MIL-101(Cr) can be explained by the intimate contact of sulfides with active PW3− sites owing the strong attraction of BMIm+ cation with the sulfides.

Structure-Property Relationships of CO2 Absorbing Core-Shell Microparticles with Encapsulated Ionic Liquid.

The demand for new ionic liquid (IL)-based systems to selectively sequester carbon dioxide from gas mixtures has prompted the development of individual components involving the tailored design of IL themselves or solid-supported materials that provide excellent gas permeability of the overall material as well as the ability to incorporate large amounts of ionic liquid. In this work, novel IL-encapsulated microparticles comprising a cross-linked copolymer shell of β-myrcene and styrene and a hydrophilic core of the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) are proposed as viable materials for CO2 capture. Water-in-oil (w/o) emulsion polymerization of different mass ratios of β-myrcene to styrene (i.e. 100/0, 70/30, 50/50, 0/100) yielded IL-encapsulated microparticles, where the encapsulation efficiency of [EMIM][DCA] was dependent on the copolymer shell composition. Thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that both thermal stability and glass transition temperatures depend on the mass ratio of β-myrcene to styrene. Images from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microparticle shell morphology as well as measure the particle size perimeter. Particle sizes were found to be between 5 and 44 μm. CO2 sorption experiments were conducted gravimetrically using TGA instrumentation. Interestingly, a trade-off between CO2 absorption capacity and ionic liquid encapsulation was observed. While increasing the β-myrcene content within the microparticle shell increases the amount of encapsulated [EMIM][DCA], the observed CO2 absorption capacity did not increase as expected due to reduced porosity compared to microparticles with higher styrene content in the microparticle shell. [EMIM][DCA] microcapsules with a 50/50 weight ratio of β-myrcene/styrene showed the best synergistic effect between spherical particle diameter (32.2 μm), pore size (0.75 μm), and high CO2 sorption capacity of ∼0.5 mmol CO2/g sample within a short absorption period of 20 min. Therefore, core-shell microcapsules composed of β-myrcene and styrene are envisioned as a promising material for CO2 sequestration applications.

Separation of CO2/N2 mixtures by new IL/Acrylic polymer microcapsules designed by a one-step suspension-based polymerization encapsulation process

In this study, we developed a one-step simplified suspension-based polymerization process for encapsuling ionic liquids (ILs) ([emim][TfO] and [emim][Tf2N]). Acrylic photoreactive monomers were cured using UV-365 light during the encapsulation process forming the capsule shell. The acetone extraction test confirmed IL encapsulation proving a high encapsulation efficiency for all samples (>80 %). For capsules produced with lower IL content, a homogeneous morphology was observed when compared to capsules with higher IL content. Suspension polymerization produced microcapsules presenting polynuclear morphology, as seen in TEM analysis. CO2 sorption ability and CO2/N2 selectivity of the produced capsules were superior when compared to pristine shell material. Capsule stability was proved by submitting the samples to several sorption/desorption cycles. [emim][TfO] microcapsules with low ILs concentration presented superior CO2 sorption results, 53 ± 0.9 mgCO2.g−1 (0.4 Mpa at 45 °C), and CO2/N2 selectivity, 4.5 ± 0.2, compared to [emim][Tf2N] microcapsules. The improvement in sorption capacity of [emim][TfO] microcapsules was greater than 50 % in comparison with the pristine shell material. Electronic structure modeling corroborated the experimental results proving that [emim][TfO] is better to separate CO2/N2 thanks to three electron-rich oxygens. The sorption results allied to the easiness of the process represents a significant contribution to the scientific development of a new, efficient, and simplified method for the encapsulation of ionic liquids, which can be applied in the capture of CO2 in industrial exhaust gas streams.

Selective Encapsulation of Ionic Liquids in UiO-66-NH2 Nanopores for Enhanced Humidity Sensing

Metal organic frameworks (MOFs) with certain pore structures are beneficial for encapsulating small molecules and realizing functional applications. In this work, ionic liquids (ILs) with similar chemical structures and different molecular sizes were in situ encapsulated in UiO-66-NH2 nanopores in the synthesis process. IL with a molecular size comparable to UiO-66-NH2 nanopores could be effectively encapsulated. The prepared ILs@MOF-based sensor shows good sensing performance in the relative humidity (RH) range (5–95%) with a small humidity hysteresis of 1.0% RH and good stability, and found the response value is closely related to the IL encapsulated amount. The multifunctional applications of the optimized sensor in human breath, skin humidity, and low humidity detection were explored. This work proves the importance of size selection in preparing ILs@MOF nanomaterials with low leakage risk for specific functionalization.

Construction of ionic liquid-filled silica shell microcapsules based on emulsion template and evaluation of their adsorption properties toward 3,4,5-trichlorophenol after various surface functionalization

The development of environmentally friendly and efficient methods for the removal of Phenolic endocrine disruptors (PEDs) from aqueous is essential to protect the environment and human health. In this work, sol–gel method and emulsion template approach were combined and applied to construct 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid-filled silica-shell microcapsules (SiO2@IL). And amino, halogen and long-chain alkanes surface-functionalized silica-shell encapsulated ionic liquid microcapsules (SiO2-NH2@IL, SiO2-Cl@IL, and SiO2-C16@IL) were successfully formulated by silica layer modification techniques. The microcapsules have homogeneous dimensions, about 1 µm, and high loading, about 92 wt% of ILs. Four microcapsules showed high adsorption properties and excellent regeneration performance for removing 3,4,5-trichlorophenol (3,4,5-TCP), which benefited from the excellent performance of [BMIM]PF6 on the extraction of 3,4,5-TCP and the enhanced hydrophobic and electrostatic effects of the surface modified microcapsules. The maximum adsorption capacity of SiO2@IL, SiO2-NH2@IL, SiO2-Cl@IL and SiO2-C16@IL calculated from the Langmuir model was 1047, 1207, 1108 and 1145 mg g−1 at 25 °C, respectively. The main factors affecting the extraction performance were the hydrophobicity and steric hindrance of [BMIM]PF6. After three regeneration cycles, the adsorption capacity and desorption efficiency of microcapsules were still above 90 %. The functionalization of the shell layer enhances the hydrophobic and electrostatic effects, which is conducive to the adsorption process, and provides some theoretical and data support for the subsequent construction of ionic liquid encapsulation materials for chlorophenol removal.

Study of high‐temperature proton exchange membrane through one‐step encapsulation of ionic liquid in sulfonated poly(ether ether ketone)

AbstractThe proton exchange membrane (PEM) is the core component of a high‐performance proton exchange membrane fuel cell (PEMFC). Since the traditional PEM has the disadvantages of poor cell performance and high cost, a new kind of PEM with good proton conductivity, low cost and simple preparation should be explored. In this paper, several different binary hybrid membranes were successfully prepared through one‐step encapsulation of different ionic liquids (ILs) in sulfonated poly(ether ether ketone) (SPEEK). The prepared membranes were characterized by scanning electron microscope (SEM), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectroscopy (XPS), proton conductivity measurements and dynamic mechanical analysis (DMA). SEM images showed that ILs were fully doped into SPEEK. FT‐IR and XPS proved that SPEEK and IL formed a new chemical bond combined with intermolecular hydrogen bonds. The TG results showed that the binary hybrid membranes could maintain stability even at 300°C. The water uptake and swelling ratio showed that the water absorption capacity of the binary composite membrane played a vital role in improving proton conductivity. The proton conductivity study showed that ILs doping also helped to improve the proton conductivity of the SPEEK membrane. When the doping amount of IL was maintained at 30 wt.%, it has the highest proton conductivity, 25 mS cm−1 at 120°C. It was proved that anhydrous hybrid membrane tetraphenyl imidazole sulfate/SPEEK ([IM2][H2PO4]/SPEEK) could be used in PEMFC at medium temperature.

Impact of Shell Composition on Dye Uptake by Capsules of Ionic Liquid.

Encapsulation of ionic liquids (ILs) has been shown to be an effective technique to overcome slow mass transfer rates and handling difficulties that stem from the high viscosity of bulk ILs. These systems commonly rely on diffusion of small molecules through the encapsulating material (shell), into the IL core, and thus the composition of the shell impacts uptake performance. Herein, we report the impact of polymer shell composition on the uptake of the small molecule dye methyl red from water by encapsulated IL. Capsules with core of 1-hexyl-3-methylimidazolium bis(trifluorosulfonyl)imide ([Hmim][TFSI]) were prepared by interfacial polymerization in emulsions stabilized by graphene oxide (GO) nanosheets; the use of different diamines and diisocyanates gave capsule shells with polyureas that were all aliphatic, aliphatic/aromatic, and aliphatic/polar aprotic. These capsules were then added to aqueous solutions of methyl red at different pH values, and migration of the dye into the capsules was monitored by UV-vis spectroscopy, compared to the capsule shell alone. Regardless of the polymer identity, similar extents of dye uptake were observed (>90% at pH = 2), yet capsules with shells containing polyureas with polar aprotic linkages took longer to reach completion. These studies indicate that small changes in capsule shell composition can lead to different performance in small molecule uptake, giving insight into how to tailor shell composition for specific applications, such as solvent remediation and gas uptake.

Exploring ionic liquid-laden metal-organic framework composite materials as hybrid electrolytes in metal (ion) batteries.

This review focuses on the combination of metal-organic frameworks (MOFs) and ionic liquids (ILs) to obtain composite materials to be used as solid electrolytes in metal-ion battery applications. Benefiting from the controllable chemical composition, tunable pore structure and surface functionality, MOFs offer great opportunities for synthesizing high-performance electrolytes. Moreover, the encapsulation of ILs into porous materials can provide environmentally benign solid-state electrolytes for electrochemical devices. Due to the versatility of MOF-based materials, in this review we also explore their use as anodes and cathodes in Li- and Na-ion batteries. Finally, solid IL@MOF electrolytes and their implementation into Li and Na batteries have been analyzed, as well as the design and advanced manufacturing of solid IL@MOF electrolytes embedded on polymeric matrices.

Capsules with polyurea shells and ionic liquid cores for CO2 capture

AbstractMany ionic liquids (ILs) have good solubilities of CO2 but the high viscosity of ILs makes them cumbersome and kinetically limits gas uptake. Encapsulation of ILs is an effective approach to overcoming these limitations. In capsules with a core of IL, the chemical composition of the shell impacts performance. Here, we report the preparation of capsules with a core of the IL [Bmim][PF6] and polymer composite shell, then evaluate how the identity of the polymer impacts CO2 uptake. IL‐in‐oil Pickering emulsions stabilized by nanosheets are used, with capsules formed by interfacial polymerization between different diamines and diisocyanates (e.g., shells are polyurea and nanosheets). The capsules contain 60–80 wt% IL and the composition was verified using Fourier transform infrared spectroscopy. Optical microscopy, scanning electron microscopy, and particle sizing data showed spherical, discrete capsules with 50–125 μm in diameter. All capsules are stable up to 250°C. Brunauer–Emmett–Teller analysis of CO2 gas uptake data showed that different polymer compositions led to different CO2 uptake properties, with capacity ranging from 0.065 to 0.025 moles of CO2/kg sorbent at 760 torr and 20°C. This work demonstrates that the polymer identity of the shell impacts gas uptake properties and supports that shell composition can tailor performance.

Controllable synthesis of polyoxymethylene dimethyl ethers by ionic liquids encapsulated in mesoporous SBA-16

Abstract The promising combustion and emission properties of polyoxymethylene dimethyl ethers (PODEn) are of significant interest. However, the synthesis of PODEn products with desired chain lengths is still a problem facing synthetic PODEn. Herein, a series of unique IL@SBA-16-Cx solid catalysts are prepared by encapsulation of ionic liquids (ILs) within the nanocage of SBA-16 through a silylation method. The structure of the encapsulated catalyst was characterized by UV–vis spectra, Fourier transform infrared (FT-IR), N2 adsorption–desorption isotherms, Powder X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Elemental analysis. The encapsulated catalysts show similar catalytic activity to the homogeneous counterparts and display higher selectivity to the targeted PODE3–5 products than their homogeneous counterparts in the synthesis of PODEn from methanol (MeOH) and trioxymethylene (TOM). The encapsulated catalysts exhibit a superior PODE3–5 selectivity and could be the promising catalysts for PODEn synthetic reaction.

Autocatalyzed interfacial thiol–isocyanate click reactions for microencapsulation of ionic liquids

In recent years, ionic liquids (ILs) have received increasing attention because of low vapor pressure, environment friendliness, good thermal and chemical stability and strong solubility. However, the liquid nature and high viscosity restrict their applications in some fields. Encapsulation of ILs is an attractive way to handle them easily. Herein, we proposed a facile method to prepare IL-loaded microcapsules using IL-in-oil emulsion as template, poly(amide-thioether) as surfactant and interfacial thiol–isocyanate click reaction for shell formation. In this system, core materials ILs were proved to be able to catalyze thiol–isocyanate reaction without side products, which significantly simplified the preparation process of microcapsules. The shell of the microcapsules was composed of polythiourethane and poly(amide-thioether), which provided a strong protection for ILs. In addition, compared with IL-in-water emulsion, the application of IL-in-oil emulsion avoided the side reactions of the highly active isocyanate. The IL content of the resulted microcapsules could reach as high as 70 wt.%. It was also demonstrated that the proposed encapsulation technology was suitable for ILs with different polarities. This work provides an efficient way to encapsulate ILs using emulsion template, which will make ILs find widespread applications across various fields.

Encapsulation of ionic liquids into POMs-based metal–organic frameworks: screening of POMs-ILs@MOF catalysts for efficient cycloolefins epoxidation

A series of ionic liquids (ILs, 1-octyl-3-methylimidazolium bromide)-functionalized polyoxometalates (POMs)-based metal–organic frameworks (MOFs) hybrids (i.e., POMs-ILs@MOFs) were facilely prepared via encapsulation strategy. The as-synthesized materials were well characterized via XRD, FT-IR, N2 sorption, TEM, SEM, UV–Vis DRS, TG, XPS, and ICP analysis to confirm that POMs was successfully immobilized in MOFs cages and the structure of MOFs were retained after immobilization. The obtained composites were screened for catalytic cycloolefins epoxidation with H2O2, and an enhanced catalytic activity was obtained via ILs modification. One of the POMs-ILs@MOFs hybrids, PMo10V2-ILs@MIL-100(Fe), when acted as the catalyst, exhibited superior catalytic properties (viz., activity and stability). Further investigation revealed that this excellent catalytic performance could be ascribed to synergistic influence of ILs, POMs, and MOFs: (1) mesoporous cages and large surface area of MIL-100(Fe) could provide suitable accommodation for reactants molecules and active species; (2) PMo10V2-ILs@MIL-100(Fe), where two Mo atoms were substituted via two V atoms, displayed stronger acidity than that of PMo12-ILs@MIL-100(Fe), and this was advantageous to cycloolefins oxidation; (3) Imidazolium cations originated from ILs were beneficial to activate POMs. Furthermore, PMo10V2-ILs@MIL-100(Fe) could be facilely recovered and maintained excellent catalytic activity over 12 cycles. Having a combination of superior catalytic activity, good recyclability, and eco-sustainability, PMo10V2-ILs@MIL-100(Fe) therefore provided a new perspective for cycloolefins epoxidation.

Encapsulation of Ionic Liquids for Tailored Applications.

This spotlight article highlights the favorable impact encapsulation of ionic liquids (ILs) has on multiple advanced applications. ILs are molten salts with many attractive properties such as negligible vapor pressure, good thermal stability, and high ionic conductivity; however, their widespread implementation in advanced applications is hampered by their relatively high viscosity, which makes them difficult to handle and results in slow mass transfer rates. The ability to encapsulate IL in a shell holds potential to impact many applications, including separations, gas sequestration, and energy storage and management, given that the capsule structure provides high surface area compared to that of bulk IL and also allows handling of the IL as a solid. Herein, we discuss encapsulation of ILs using different approaches and highlight the contributions from our lab in both capsule preparation and application. Specifically, we have developed the ability to use 2D carbon nanoparticle surfactants and interfacial polymerization to prepare capsules of IL using both IL-in-water and IL-in-oil Pickering emulsions as templates. This facile, one-step method to encapsulate ILs gives structures with beneficial performance in supercapacitors, separations, and CO2 sequestration, as discussed herein. We conclude this spotlight with an outlook on how to improve upon these systems for next-generation applications.

Recyclability of Encapsulated Ionic Liquids for Post-Combustion CO2 Capture

Ionic liquids (ILs) with aprotic heterocyclic anions (AHAs) are promising candidates for post-combustion carbon capture technologies since they react with CO2 stoichiometrically and reversibly. CO2 solubilities in two AHA-ILs, triethyl(octyl)phosphonium 2-cyanopyrrolide ([P2228][2CNPyr]) and triethyl(octyl)phosphonium benzimidazolide ([P2228][BnIm]), are reported for multiple temperatures and a third, triethyl(octyl)phosphonium 6-bromobenzimidazolide ([P2228][6-BrBnIm]), at one temperature. Ionic liquid [P2228][2CNPyr] and phase-change ionic liquid (PCIL) tetraethylphosphonium benzimidazolide ([P2222][BnIm]) were encapsulated in a chemically compatible and CO2-permeable polydimethylsiloxane (PDMS) polymer shell in order to enhance absorption and desorption kinetics. Both the free and encapsulated [P2228][2CNPyr] and [P2222][BnIm] were subjected to thermodynamic testing. The CO2 solubilities in the encapsulated IL and PCIL were in good agreement with the free IL and PCIL, meaning that the encapsulation of IL and PCIL greatly enhanced the kinetics of CO2 absorption while maintaining the high CO2 capture capacity. Recyclability testing was also performed on both the free and encapsulated [P2228][2CNPyr] and [P2222][BnIm]. The IL and PCIL materials, as well as the capsules, were stable upon cycling, with the CO2 capacities for each cycle remaining unchanged. The IL and the PCIL showed no sign of degradation after cycling, which demonstrated excellent performance.

Microfluidic Generation of Microsprings with Ionic Liquid Encapsulation for Flexible Electronics.

Inspired by helical or spiral veins, which endow plants with excellent flexibility and elasticity to withstand storms, we present novel hollow microsprings with ionic liquid encapsulation for flexible and stretchable electronics. The microsprings were generated by using a coaxial capillary microfluidic device to consecutively spin poly(vinylidene fluoride) (PVDF) presolution and an ionic liquid, which formed laminar flows in the coaxial injection microfluidic channels. The fast phase inversion of PVDF helps to form the core-shell structure of a microfiber and guarantees the in situ encapsulation of ionic liquid. The hybrid microfiber can then spiral and be further solidified to maintain the helical structure with increasing flow rates of the injection fluids. Because of the feasible and precise control of the injection fluids during the microfluidic spinning, the resultant microsprings have controlled core-shell structures, helical pitches, and corresponding electromechanical properties. By further embedding them into stretchable films, the simple paradigm of a flexible device shows great conductive performance in tensile tests and even motion cycles, which could be explored as a promising candidate in stretchable sensors, flexible electronics, and electronic skins.

Ionic Conduction in Metal–Organic Frameworks with Incorporated Ionic Liquids

Encapsulation of ionic liquids (ILs) into porous materials can provide environmentally benign solid-state electrolytes for various electrochemical devices, in particular, porous metal–organic frameworks (MOFs) that enable us to tailor their framework and pore structures by varying central metals and organic linkers as well as the ILs with an unlimited number of possible cation–anion combinations. Therefore, rational materials design based on the accumulated knowledge about the relationship between materials and functionalities is essential for studying IL@MOF hybrid composites with desired properties. In this Review, we first introduce synthetic methodologies to incorporate ILs into MOFs, especially based on the postimpregnation approach. Interactions and the distribution of component ions of the ILs within the MOFs are discussed from the viewpoint of ion mobility, which is responsible for the performance of electrochemical devices. Finally, we devote attention to the ion-conducting properties, including ...

CO2 selective metal organic framework ZIF-8 modified through ionic liquid encapsulation: A computational study

Nano-scale porous solids are alternate candidates for CO2 handling towards the development of materials for post-combustion CO2 capture with low energy demands and milder operating conditions. Zeolitic imidazolate framework-8 (ZIF-8) is one of the most investigated Metal Organic Frameworks (MOFs) for separation of gas mixtures. In this work, we investigate a new approach of tailoring MOF separation efficiency, by confining pairs of [bmim+][Tf2N−] ionic liquid (IL) in the cages of ZIF-8 (IL@ZIF-8). Molecular force fields, developed by the authors for both the ZIF-8 framework and the [bmim+][Tf2N−] IL, are used in molecular simulations of the system. Monte Carlo simulations are used for sorption of CO2/CH4 and CO2/N2 mixtures computations. The results show an increase of the CO2 sorption due to the presence of the IL, which increases CO2 selectivity and capacity dramatically. Recently reported experiments agree with our findings. Moreover, we explore how CO2 selectivity and capacity varies with IL composition in the IL@ZIF-8 complex, as means to define an optimum IL composition in terms of the separation efficiency.