IL Content Research Articles

Hydrogels composite optimized for low resistance and loading–unloading hysteresis for flexible biosensors

With the advancement of wearable and implantable medical devices, hydrogel flexible bioelectronic devices have attracted significant interest due to exhibiting tissue-like mechanical compliance, biocompatibility, and low electrical resistance. In this study, the development and comprehensive performance evaluation of poly(acrylic acid)/ N,N′-bis(acryloyl) cystamine/ 1-butyl-3-ethenylimidazol-1-ium:bromide (PAA/NB/IL) hydrogels designed for flexible sensor applications are introduced. Engineered through a combination of physical and chemical cross-linking strategies, these hydrogels exhibit strong mechanical properties, high biocompatibility, and effective sensing capabilities. At 95 % strain, the compressive modulus of PAA/NB/IL 100 reach up to 3.66 MPa, with the loading–unloading process showing no significant hysteresis loop, indicating strong mechanical stability and elasticity. An increase in the IL content was observed to enlarge the porosity of the hydrogels, thereby influencing their swelling behavior and sensing functionality. Biocompatibility assessments revealed that the hemolysis rate was below 5 %, ensuring their suitability for biomedical applications. Upon implantation in rats, a minimal acute inflammatory response was observed, comparable to that of the biocompatibility control poly(ethylene glycol) diacrylate (PEGDA). These results suggest that PAA/NB/IL hydrogels hold promise as biomaterials for biosensors, offering a balance of mechanical integrity, physiological compatibility, and sensing sensitivity, thereby facilitating advanced healthcare monitoring solutions.

Ionic Thermoelectric Generators in Vertical and Planar Topologies Based on Fluorinated Polymer Hybrid Materials with Ionic Liquids.

Ionic thermoelectrics (TEs), in which voltage generation is based on ion migration, are suitable for applications based on their low cost, high flexibility, high ionic conductivity, and wide range of Seebeck coefficients. This work reports on the development of ionic TE materials based on the poly(vinylidene fluoride-trifluoroethylene), Poly(VDF-co-TrFE), as host polymer blended with different contents of the ionic liquid, IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][TFSI]. The morphology, physico-chemical, thermal, mechanical, and electrical properties of the samples are evaluated together with the TE response. It is demonstrated that the IL acts as a nucleating agent for polymer crystallization. The mechanical properties and ionic conductivity values are dependent on the IL content. A high room temperature ionic conductivity of 0.008 S cm-1 is obtained for the sample with 60 wt% of [EMIM][TFSI] IL. The TE properties depend on both IL content and device topology-vertical or planar-the largest generated voltage range being obtained for the planar topology and the sample with 10 wt% of IL content, characterized by a Seebeck coefficient of 1.2 mV K-1. Based on the obtained maximum power density of 4.9 µW m-2, these materials are suitable for a new generation of TE devices.

Stability of Quadruple Hydrogen Bonds in an Ionic Liquid Environment.

Hydrogen bonds (H-bonds) are highly sensitive to the surrounding environments owing to their dipolar nature, with polar solvents kown to significantly weaken H-bonds. Herein, the stability of the H-bonding motif ureidopyrimidinone (UPy) is investigated, embedded into a highly polar polymeric ionic liquid (PIL) consisting of pendant pyrrolidinium bis(trifluoromethylsulfonyl)imide (IL) moieties, to study the influence of such ionic environments on the UPy H-bonds. The content of the surrounding IL is changed by addition of an additional low molecular weight IL to further boost the IL content around the UPy moieties in molar ratios of UPy/IL ranging from 1/4 up to 1/113, thereby promoting the polar microenvironment around the UPy-H-bonds. Variable-temperature solid-state MAS NMR spectroscopy and FT-IR spectroscopy demonstrate that the UPy H-bonds are largely present as (UPy-) dimers, but sensitive to elevated temperatures (>70°C). Subsequent rheology and DSC studies reveal that the ILs only solvate the polymeric chains but do not interfere with the UPy-dimer H-bonds, thus accounting for their high stability and applicability in many material systems.

Improved CO2/N2 separation performance by relatively continuous and defect-free distribution of IL-encapsulated ZIF-67 in ion gel membranes

Metal-organic frameworks (MOFs), as a typical type of porous materials, are widely used as fillers in mixed matrix membranes (MMMs) to enhance the gas separation performance. However, non-selective interface defects are prone to appear in MMMs under high MOF loading conditions, meanwhile, the discontinuous dispersion of MOF particles in polymeric matrices makes the gas molecules diffuse along the MOF-polymer-MOF intersection path and difficult to achieve efficient molecular transfer. These factors greatly compromise the ability of MOF to enhance membrane separation performance. Herein, the [C5min][BF4] encapsulated ZIF-67 (IL@ZIF) composites were embedded into the defect-free IL/Pebax ion gel matrix to form a mixed matrix ion gel membrane without interface defects. On the basis of good interfacial compatibility, the relatively continuous and highly selective CO2 transmission channels were constructed via increasing the filler loading up to 80 wt%. In this context, the typical IL@ZIF/IL/Pebax membrane with 80 wt% IL content and 70 wt% IL@ZIF doping amount exhibits a CO2 permeability of 408.2 Barrer and CO2/N2 selectivity of 97.2, surpassing the latest upper line. This work may have high reference value in the construction and preparation of MOF-based MMMs with high performance in gas separation.

Ionic Liquids Facilitate the Dispersion of Branched Polyethylenimine Grafted ZIF-8 for Reinforced Epoxy Composites.

Metal-organic frameworks (MOFs) have been previously shown as an emerging modified class of epoxy resin. In this work, we report a simple strategy for preventing zeolitic imidazolate framework (ZIF-8) nanoparticles from agglomerating in epoxy resin (EP). Branched polyethylenimine grafted ZIF-8 in ionic liquid (BPEI-ZIF-8) nanofluid with good dispersion was prepared successfully using an ionic liquid as both the dispersant and curing agent. Results indicated that the thermogravimetric curve of the composite material had no noticeable change with increasing BPEI-ZIF-8/IL content. The glass transition temperature (Tg) of the epoxy composite was reduced with the addition of BPEI-ZIF-8/IL. The addition of 2 wt% BPEI-ZIF-8/IL into EP effectively improved the flexural strength to about 21.7%, and the inclusion of 0.5 wt% of BPEI-ZIF-8/IL EP composites increased the impact strength by about 83% compared to pure EP. The effect of adding BPEI-ZIF-8/IL on the Tg of epoxy resin was explored, and its toughening mechanism was analyzed in combination with SEM images showing fractures in the EP composites. Moreover, the damping and dielectric properties of the composites were improved by adding BPEI-ZIF-8/IL.

Removal of Hexavalent Chromium using a PVDF-based Polymer Inclusion Membrane with a phosphonium-based ionic liquid

Hexavalent chromium (Cr(VI)) is widely used in industrial processes and products while it possess a severe health effect to living being and environmental hazard. Removing Cr(VI) from industrial wastewater and other contaminated sources is important for human health and the ecosystem. Various treatment technologies have been developed to remove it, but further research is needed to improve their effectiveness. This report discusses the adsorption of Cr(IV) using a phosphonium-based ionic liquid, trioctyldodecylphosphonium chloride, in a polymer inclusion membrane (PIM) matrix. The PIM's chemical structure was also examined by FTIR spectroscopy, and a cross-sectional SEM image was taken. The adsorption efficiency of PIM increase as the IL content increase, and experiencing a significant jump in over 30% of IL content. The maximum adsorption capacity corresponds to PIM40 and PIM50, which shown a 90% adsorption in 24 hours. However, PIM50 was difficult to regenerate and reuse due to membrane stability. Cr(VI) adsorption by PIM40 followed a pseudo-second-order kinetic model and Langmuir isotherm model with adsorption capacity of 74.1 mg g-1. Following the isotherm model, the adsorption of Cr(VI) probably through an anionic exchange between IL in the PIM and Cr(VI) complex. Cr(VI) desorption from PIM40 was carried out by using a 0.5 mol L-1 NaNO3.The PIM40 was able to be reused for five times without a significant change in the performance. This study has shown that PIM can effectively remove heavy metals from water and selectively remove specific contaminants. PIM are also relatively easy to regenerate or replace, making them a potentially cost-effective method for removing heavy metals from water.

SBA-15 Supported Benzimidazolium-based Ionic Liquids: Synthesis, Characterization, and Applications in the Fuel Desulfurization

SBA-15 supported benzimidazolium-based ionic liquid ([email protected][BzIm][Cl]) has been synthesized with immobilization of trimethoxysilane-modified 1-methylbenzimidazolium chloride ([BzIm][Cl]) onto synthesized SBA-15 silica support material. SBA-15 and [email protected][BzIm][Cl] were characterized using FTIR, SEM, TEM, EDS, SAXS, BET, and NMR spectroscopy. The variation was found in the morphology as well as structure of [email protected][BzIm][Cl] with variation in the content of [BzIm][Cl]. The application of synthesized SBA-15 supported [BzIm][Cl] was studied for the removal of sulfur compounds from model fuel and real gasoline samples. It was found that in contrast to pure SBA-15, supported ionic liquids (SILs) showed higher efficiency for the adsorption of different sulfur-containing aromatic heterocyclic compounds from model fuel. Similarly, SIL having large IL content was found more efficient in the removal of sulfurous compounds from model and real gasoline samples in comparison to SIL having lesser IL content. Moreover, the adsorbents were reused 10 times without any significant loss in adsorption efficiency.

Transparent, self-healable, shape memory poly(vinyl alcohol)/ionic liquid difunctional hydrogels assembled spontaneously from polymer solution

Self-healable, shape memory poly(vinyl alcohol) (PVA)/ionic liquid (PVA/IL) hydrogels were assembled from poly(vinyl alcohol) and 1-butyl-3-methylimidazolium tetrafluoroborate solutions by a one-step strategy at room temperature. The gelation was due to the judicious design ofthe supermolecular interactions between PVA and IL, including electrostaticinteractions and hydrogen bonding. Differential scanning calorimetry and tensile tests etc. were applied to study the effect of IL on the hydrogels. The results showed that the optimum thermal and mechanical properties of the hydrogel are obtained with higher IL content. The tensile strength and elongation at break of PVA/IL-1.00 hydrogel were 1.447 MPa and 750%, respectively. The self-healing efficiency reached up to 92.60%. Due to the reversible metal ion cooperation in ferric sulfate and the reduction of Fe3+ in ascorbic acid, the hydrogels exhibited a redox-stimulated shape memory effect. The cytotoxicity test indicated the promising applications for biomedical materials including artificialskin and wounddressings.

Polyaniline grown on poly(vinyl alcohol)/ionic liquid composite film as electrodes for flexible and self-healable solid-state polymer supercapacitors

Flexible solid-state supercapacitors are considered as one kind of competitive energy storage devices due to the excellent flexibility and high specific capacitance. It attracts considerable attention in recent years. In this paper, binder-free polymer electrodes with outstanding electrochemical performance and mechanical properties were fabricated using poly (vinyl alcohol)/ionic liquid (PVA/IL) composite films as the substrates for the in-suit polymerization of aniline. Scanning electron microscope, cyclic voltammetry, galvanostatic charge-discharge, and tensile test were applied to study the effect of IL content on the structure and properties of the polymer electrodes polyaniline/poly(vinyl alcohol)/ionic liquid (PANI/PVA/IL). The electrode PANI/PVA/IL-1.0 has the optimal comprehensive performance. The specific capacitance and conductivity were 266.6 mF cm −2 and 6.49 S m −1 at 1 mA cm −2 . The tensile strength and elongation at break could reach 1.27 MPa and 509.19%, respectively. PANI/PVA/IL-1.0 was used to assemble the symmetrical polymer supercapacitor with polymer gel electrolyte (PVA/H 2 SO 4 /IL). The area specific capacitance was 251.2 mF cm −2 at 1 mA cm −2 with the capacitance retention of 77.2% after 1000 charge-discharge cycles. Moreover, the solid-state polymer supercapacitor could keep excellent electrochemical performance even under different bending angles or after self-healing, which provides potential applications in electronic encapsulation, flexible energy-storage devices, and high stretchable electric devices etc. The polyaniline/poly(vinyl alcohol)/ionic liquid based electrodes exhibit outstanding electrical and mechanical performance, which endows the solid-state polymer supercapacitors excellent specific capacitance, flexibility and self-healing. • Flexible and self-healable supercapacitors were fabricated using poly(vinyl alcohol)-ionic liquid as substrates. • High tensile strength at break of the polymer indicated its outstanding flexibility due to the presence of ionic liquid. • The fabricated solid-state polymer supercapacitor has good specific capacitance, flexibility and self-healing function.

Imidazolium and picolinium-based electrolytes for electrochemical reduction of CO2 at high pressure

Ionic liquid-based aqueous electrolytes with reduced IL content for coupling CO2 capture and electrochemical reduction.

Recovery of enzyme structure and activity following rehydration from ionic liquid.

Long-term preservation of proteins at room temperature continues to be a major challenge. Towards using ionic liquids (ILs) to address this challenge, here we present a combination of experiments and simulations to investigate changes in lysozyme upon rehydration from IL mixtures using two imidazolium-based ILs (1-ethyl-3-methylimidazolium ethylsulfate, [EMIM][EtSO4] and 1-ethyl-3-methylimidazolium diethylphosphate, [EMIM][Et2PO4]). Various spectroscopic experiments and molecular dynamics simulations are performed to ascertain the structure and activity of lysozyme. Circular dichroism spectroscopy confirms that lysozyme maintains its secondary structure upon rehydration, even after 295 days. Increasing the IL concentration decreases the activity of lysozyme and is ultimately quenched at sufficiently high IL concentrations, but the rehydration of lysozyme from high IL concentrations completely restores its activity. Such rehydration occurs in the most common lysozyme activity assay, but without careful attention, this effect on the IL concentration can be overlooked. From simulations we observe occupation of [EMIM+] ions near the vicinity of the active site and the ligand-lysozyme complex is less stable in the presence of ILs, which results in the reduction of lysozyme activity. Upon rehydration, fast leaving of [EMIM+] is observed and the availability of active site is restored. In addition, suppression of structural fluctuations is also observed when in high IL concentrations, which also explains the decrease of activity. This structure suppression is recovered after undergoing rehydration. The return of native protein structure and activity indicates that after rehydration lysozyme returns to its original state. Our results also suggest a simple route to protein recovery following extended storage.

Ionic liquids filled hybrid capsules by harnessing interfacial imine chemistry of Janus nanosheets stabilized pickering emulsion for removal of chlorophenols

Ionic liquids filled hybrid capsules (C-IL) hold promise as extraction medium to remove phenolic endocrine disruptors (PEDs), which are priority pollutants because of their high persistence and toxicity. Nonetheless, preparation of uniformly sized C-IL has stand out as the major drawback for their use on adsorption applications. In this work, Janus graphene oxide (J-GO) nanosheets stabilized Pickering emulsion incorporated with interfacial imine chemistry were used for synthesis of polymer shell encapsulated 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), and then as-prepared hybrid capsules (C-IL/W) were considered as a novel material for 3,4,5-trichlorophenol (3,4,5-TCP) capture. Uniformly sized C-IL/W (180 μm in diameter) had high IL content of 90 wt%, and its shell thickness from quick interfacial imine chemistry in situ is about 2.0 to 2.5 μm. Benefiting from the strong hydrogen bonding and π-π conjugation of the two aromatic rings with loaded [BMIM]PF6, the maximum adsorption capacity calculated from Langmuir model was 6775 mg g−1 at 25 °C for 3,4,5-TCP. Through the principal component analysis (PCA), the facts that chlorine substituent such as its number and location posed a significant influence on the PEDs extraction efficiency were confirmed, which followed the order: 2-chlorophenol (2-CP) < 2,6-dichlorophenol (2,6-DCP) < 2,4-dichlorophenol (2,4-DCP) < 3,4,5-TCP. The hydrophobicity and steric hindrance upon [BMIM]PF6 were the main factors affecting the extraction performance. After three regeneration cycles, the adsorption capacity of capsules towards 3,4,5-TCP was 79% of the first cycle, and the desorption efficiency was still above 90%. The results not only demonstrated an important method to design C-IL for PEDs removal, but also suggested the possible mechanism for chlorophenols extraction.

Enhancing the properties of PBAT/PLA composites with novel phosphorus-based ionic liquid compatibilizers

Biodegradable polybutylene adipate terephthalate/polylactic acid (PBAT/PLA) composites with good interfacial adhesion, mechanical properties, flame retardancy and melt processability are demanded by the plastics sector. To simultaneously achieve these attributes, researchers are actively seeking novel compatibilizers for these polymers. Herein, two ionic liquids (denoted as IL1 and IL2), comprising phosphonium cations (PR4+) with different length alkyl substituents (R) and phosphorus containing asymmetric anions (RPO32−), were successfully synthesized and applied as compatibilizers to prepare PBAT/ILs/PLA composites by melt blending and injection molding. Owing to chain entanglement between the long alkyl chains of PR4+ and RPO32− with the PLA and PBAT polymer chains, as well as interactions between the anion -PO32− groups and ester groups on PLA and PBAT, the toughness, flame retardancy and processability of the composites were all enhanced. Adding the ILs resulted in the more uniform dispersion of PLA in the PBAT matrix. The elongation at break of composites containing 0.4 wt.% IL1 or IL2 increased by 329.9 % and 168.5 %, respectively, relative to pristine PBAT/PLA composites. At an IL content of 0.7 wt.%, both of PBAT/IL1/PLA composites and PBAT/IL2/PLA composites possessed excellent flame retardancy (a limiting oxygen index of 28.1 and 27.3, respectively). Furthermore, the melt fluidity of the PBAT/ILs/PLA composites increased with increasing IL content. This work conclusively demonstrates that ionic liquids can serve as excellent compatibilizers for high performance biodegradable PBAT/PLA composites.

Ultrafine electrospun fiber based on ionic liquid/AlN/copolyamide composite as novel form-stable phase change material for thermal energy storage

A novel form-stable phase change material (FSPCM) based on ionic liquid/aluminum nitride/copolyamide composite were fabricated from electrospinning approach. The ionic liquid 1-hexadecyl-3-methylimidazolium bromide (IL) was chosen as phase change materials while nano aluminum nitride (AlN) and copolyamide 6/12 (CoPA) were chesen as additive and supporting matrix, respectively. The surface morphology and heat storage property had been systematically investigated by Scanning Electronic Microscopy (SEM) and Differential Scanning Calorimetry (DSC), respectively. Results showed that the diameter of the phase change fibers are 0.92–1.07 μm and was influenced by the IL and AlN content. With 57 wt% of IL and 5 wt% of AlN, the composite fiber achieved a fusion enthalpy of 86.4 J/g and the thermal conductivity was increased by 165.2% compared to that of IL/CoPA. Thermogravimetric Analysis (TGA) and thermal cycle test also indicated a good thermal stability and reusability of the composite fiber. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses indicated that new hydrogen bonds between IL and CoPA were formed in the composite and showed a significant effect on the thermal performance of the composite fibers. The electrospun composite fiber based on ionic liquids can be applied as form-stable phase change material in thermal energy storage and temperature regulation.

Voltage response of three ionic polymer pressure sensors based on ion migration at different ambient humidities

Besides bending sensor, ionic polymer materials can work as pressure sensor based on ion migration and show more potential in engineering application. To explore a better ionic polymer material for pressure sensor, three typical ionic polymer materials, Nafion, poly(vinylidene fluoride)/ionic liquid (IL/PVDF) composite, thermoplastic polyurethane/ionic liquid (IL/TPU) composite, were selected to comparatively investigate the sensing properties under an applied pressure. Ionic polymer pressure sensors with circular truncated cone structure were developed by casting method. Their voltage responses were evaluated by a self-made test platform under a series of step force. The voltage sensitivity and the stability were obtained by performing the tests at different ambient humidity levels. The sensitivity of Nafion sensor was influenced by the ambient humidity heavily, which increased from 8.97 mV N−1 (28.17 mV MPa−1) to 31.11 mV N−1 (97.69 mV MPa−1) as the relative humidity (RH) increasing from 30% RH to 90% RH. In comparison, the voltage responses of IL/TPU sensor and IL/PVDF sensor were rarely influenced by the humidity because of the stability of IL, but strongly related to the content of IL. As the IL content increasing from 30 wt.% to 50 wt.%, the sensitivity of IL/TPU sensor increased from 5.65 mV N−1 (17.74 mV MPa−1) to 16.55 mV N−1 (51.97 mV MPa−1), that of IL/PVDF sensor increased from 14.12 mV N−1 (44.33 mV MPa−1) to 32.23 mV N−1 (101.20 mV MPa−1) monotonously. The underlying mechanisms were revealed based on water exchange in air and ion transport theory qualitatively. IL/PVDF sensor with 50 wt.% IL content shows the best sensing performance in air and is promising for practical application.

Effect of the CO2-philic ionic liquid [BMIM][Tf2N] on the single and mixed gas transport in PolyActive™ membranes

This study reports on the gas transport properties of four different grades of PolyActive™ polyether-co-polyester multi-block copolymer membranes containing different concentrations (4.8, 9.1, 16.7, 23.1 and 28.6 wt%) of the low-viscous CO2-philic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]). Single gas permeability, solubility and diffusion coefficients of He, H2, N2, O2, CH4 and CO2 were determined at 1 bar and 25 °C in a constant-volume time lag setup. Mixed gas permeability measurements of CO2/CH4 and CO2/N2 mixtures containing 35 and 15 vol% CO2, respectively, were carried out at 25 °C in the pressure range from 1 to 6 bar(a). The transport properties were correlated with the ionic liquid content of the samples, the specific PolyActive™ grade (i.e. chain length, copolymer composition), and previously determined microstructure, crystallinity, thermal and mechanical properties. For all PolyActive™ grades, the single gas permeability decreased in the order CO2 ≫ H2 > He > O2 ≈ CH4 > N2 and it typically increased with increasing IL content, whereas the ideal selectivity decreased with IL content for most gas pairs. None of the membranes revealed significant dependence on the feed pressure in both single and mixed gas permeation tests. Such behavior is typical for predominantly rubber-like materials. Samples based on PolyActive™ 4000PEOT77PBT23 had the strongest dependence on the IL concentration due to its higher weight fraction and higher crystallinity of the polyether phase.The specific behavior of the four polymers was illustrated via their different trends with increasing IL concentration in the Robeson diagrams. The study demonstrates how blending with ionic liquid can be used to tailor the permeability and selectivity of the membranes. It provides insight into the influence of ionic liquid and the weight percentages of the PEO blocks and the PBT blocks in the copolymers on the individual contributions of the solubility and diffusion coefficients on the permeability.

Preparation and characterization of novel solid electrolytes based on [EMIM] BF4 and lithium nitrate confined silica gels

Novel ionic liquid ([EMIM]BF4) and lithium nitrate confined silica gel composites have been prepared via hydrolytic sol-gel process and found to exhibit electrical conductivity up to 10−4 Ω−1cm−1 in the temperature range 150–300 °C. The composites are thermally stable at this temperature range and measurements are repeatable. Powder X-ray diffraction patterns suggest that the composites are amorphous in nature. FE-SEM (EDS elemental mapping) and DSC measurements further confirm IL confinement in the matrix. Electrical conductivity (150–300 °C) has been studied as a function of IL and Li+ ion content. The samples with no IL content are essentially electronic in nature. Addition of IL in small amounts (1 mol%) enhances the total conductivity at least by an order of magnitude. Further addition of salt (LiNO3) enhances ionic transport by orders of magnitude. The electronic conductivity and ionic mobility along with OCV measurements on cells of type Li/composite/LiCoO2 suggests facilitation of Li+ ion transport in presence of IL in small amount. However, further increasing the content of IL in the composition while keeping the salt ion concentration same, does not improve conductivity, rather reduces it. This complex behavior may be due to possibility of Li+ ions forming complex with IL anion and further investigations are required in this regard. Preliminary findings suggest that these materials have good potential for their applications in all-solid-state supercapacitors.

Tuning the microstructure of crosslinked Poly(ionic liquid) membranes and gels via a multicomponent reaction for improved CO2 capture performance

Crosslinked poly(ionic liquid) (PIL) and poly(ionic liquid)-ionic liquid (PIL-IL) based membranes with tunable micromolecular structure have been synthesized in a simple way to optimize their CO2 capture performance. Amino-terminated PILs of two molecular weights (MW) were synthesized via the Debus-Radziszewski multicomponent reaction and then reacted with two commercial glycidyl ether crosslinkers, (polyoxyethylene bis(glycidyl ether) and trimethylolpropane triglycidyl ether). The effects of the PIL MW, crosslinker type and content, and IL content on CO2/N2 permeation-separation performance were systematically investigated. For the neat PIL membranes, both the utilization of ether-containing crosslinker and an increase in the crosslinker content increased the CO2 solubility and diffusivity, with the best PILs membrane exhibiting an excellent CO2 permeability of 170 Barrer and a CO2/N2 permselectivity of 36. For the PIL-IL membranes, an increase in the IL content increased the CO2 solubility and diffusivity, but also resulted in a decrease in the diffusivity selectivity. The best permeation-selectivity performance belongs to a PIL-IL membrane that showed a CO2 permeability of 2070 Barrer and a CO2/N2 permselectivity of 24.6. Among all the PIL-IL membranes reported in literature, this PIL-IL membrane demonstrated the highest permeability and also a cost-effective permselectivity, with its separation performance approaching the 2008 Robeson upper bound.

Ionic Liquid Hydrogel Composite Membranes (IL-HCMs)

In this work, novel hydrogel composites membranes comprising [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide as monomer, N,N-methylene bisacrylamide as cross-linker, and 1-butyl-3-methylimidazolium hexafluorophosphate as ionic liquid additive, have been developed. Ionic liquid hydrogel composite membranes (IL-HCMs) were tested for membrane contactors applications, aiming to reduce surface hydrophobicity of the polypropylene support, to reduce wetting tendency due to interaction with hydrophobic foulants, while affecting salts rejection in desalination operation, because of the entrapment of ILs inside the porous mesh-like structure of the gel layer. Transmembrane flux comparable to the sole polypropylene support was observed for IL content &gt; 1 wt.%. Furthermore, all IL membranes presented a larger rejection to sodium chloride than the PP support or the composites without ionic liquid inside. Although the overall transmembrane flux of IL-HCMs developed in this work is comparable with that of state of the art MD membranes, this study demonstrated that the strong hydrophilic hydrogel layer, with C.A. &lt; 50° for IL content larger than 1 wt.%, serves as a stabilization coating, by providing the new media between the feed and the hydrophobic membrane surface, thus potentially controlling the diffusion of hydrophobic foulant molecules. This would result in a decrease in the membrane wetting and fouling aptitude.

Pretreatment of corn cob in [EMIM][OAc] and [EMIM][OAc]/ethanol (water).

High cost and high viscosity of ionic liquid restricted its commercial application in pretreatment of lignocellulose. Water and ethanol were used as additive in [EMIM][OAc] to pretreat corn cob at moderate temperature (< 100°C). It was found that enzyme hydrolysis (EH) sugar yield was increased with the increase of IL content. The largest EH sugar yield of 68.8% was obtained when pure IL was used. However, for [EMIM][OAc]/ethanol, the EH sugar yield as high as 66.9% was gained when the IL content was 80%, which was comparable to that for pure IL pretreatment. In addition, Kamlet-Taft parameter was calculated to characterize the polarity solvency of binary liquid phase, to illustrate the underlying reason for the increase of EH sugar and the lignin removal. Finally, to demonstrate the crystalline and microstructure change after pretreatment, XRD and SEM were performed for the raw materials and the pretreated samples.