Poly Ionic Liquid Research Articles

Polyionic liquid ionogels formed via hydrophobic association for flexible strain sensors

A series of self-healing polyionic liquid ionogels based on hydrophobic association were designed and fabricated for application in strain sensors.

Economical Viable Liquid Poly Aluminium Chloride (PAC) Coagulation Agent Used to Treat Ceramic Industries Effluent to Remove Suspended Solid

Economical Viable Liquid Poly Aluminium Chloride (PAC) Coagulation Agent Used to Treat Ceramic Industries Effluent to Remove Suspended Solid

Synergistic effect and ionic conductivity of crosslinked imidazole ionic liquids and piperidine cations on poly(biphenyl-piperidine) anion exchange membranes

In order to prepare anion exchange membranes with good performance, and we prepared ether-free bonded poly(biphenyl-piperidine) anion exchange membranes (CQPBP-M-x, x is degree of crosslinking) by introducing cross-linked imidazolium ionic liquids. The introduction of cross-linked imidazolium ionic liquids increases multiple OH− transport sites and establishes a more pronounced microphase-separated structure with the backbone, while acting synergistically with piperidinium cations, resulting in improved membrane conductivity. Meanwhile, the introduction of an ether-free backbone and the construction of a cross-linked structure could promote the chemical stability of the membrane and effectively inhibit membrane swelling. The prepared cross-linked imidazole ionic liquid poly(biphenyl-piperidine) (CQPBP-M-30 %) membrane exhibited relatively good ionic conductivity (88.03 mS/cm), and low swelling (11.75 %) at 80 °C. The H2–O2 fuel cell performance test conducted at 80 °C without back pressure showed a peak power density of 125.7 mW/cm2. Therefore, it is a worthwhile direction to explore to improve the performance of anion exchange membranes by adopting an ether-free backbone and constructing a cross-linked structure contain multiple cationic groups.

Solar driven thermal responsive polyionic liquid/PDDA semi-IPN hydrogel for near-room temperature membrane-free osmotic desalination

The designed thermally responsive polyionic liquid (TPIL)/ poly (diallyl dimethylammonium chloride) (PDDA) hydrogel with a semi-interpenetrating (semi-IPN) structure, containing highly charged chloride anions, was fabricated to explore the comprehensive capabilities of solar driven membrane-free osmotic desalination. Introducing linear PDDA polyelectrolyte with higher charge density has effectively excluded salt ions from entering the TPIL hydrogel matrix due to the strong charge concentration gradient established between the hydrogel and the saline reservoir. Meanwhile, the thermo-sensitivity of the polyionic liquid/PDDA semi-IPN (PNCl) hydrogel enabled the release of absorbed salt-depleted water at a temperature above the Lower Critical Solution Temperature (LCST). The multiple purification process established by partial submersion of PNCl hydrogel in saline enabled continual reduction of the salt ion concentration during the upwards transportation of water along the polyelectrolyte network. Moreover, a mushroom-shaped hydrogel demonstrated enhanced the effectiveness in long-term cyclic desalination. The “mushroom cap” was loaded with photo-thermal conversion fillers (Ti3C2Tx MXene) to achieve higher photo-thermal conversion efficiency for water recovery. A record high salt rejection rate of more than 93% was obtained for membrane-free osmotic desalination. More importantly the whole desalination/water absorption/release process was solely supported by gently heating the PNCl hydrogel under the illumination of renewable solar energy.

A novel polyionic liquid with lubricity and viscosity-increasing dual functionalities as the additive in aqueous lubrication system

The polyionic liquid poly-PEGMA-r-METAC (PPM) with quaternary ammonium has been synthesized and evaluated as additive in aqueous lubricating fluids. The rheological behavior of aqueous lubricating fluids with PPM has been characterized to confirm PPM’s function as a viscosity modifier. The tribological behavior of aqueous lubricating fluids with PPM has been investigated on SRV-V and MTM testing machines. It was found that PPM has excellent viscosity-increasing, lubricating, and anti-wear properties as an additive for aqueous, which can be attributed to the ability of PPM to form the protective film and boundary tribofilm generated from complex tribochemical reaction on rubbing surface. The obtained PPM with dual functions of anti-corrosion additives and viscosity index improver can play an important role in diverse lubrication regimes.

A review on antibacterial potential of poly‐ionic liquid‐based biomaterials

AbstractIn recent years, bacterial infection has become one of the significant clinical challenges. The overuse or misuse of antibiotics increases the number of antibiotic‐resistant bacterial pathogens and causes enormous medical burdens with high morbidity and mortality. Several strategies have been adopted to tackle this; poly‐ionic liquids (PILs), a class of ionic liquids (ILs) systems demonstrating a broad spectrum of antimicrobial activities, have been widely used in biomedical applications. During polymerization, the charge density of the cations, molecular weight, and hydrophobic behavior can be regulated to accomplish more potent antibacterial efficacy with low cytotoxicity. However, inadequate literature is available highlighting the application of PIL‐based materials in biomedical applications. Keeping this in mind, the recent advances in PIL‐based biomaterials formed by conjugating PIL with natural and synthetic polymers as effective antimicrobial agents have been the focus area of this review.

Dual−crosslinked polyionic liquid polymer electrolyte with optimal balance of ion conductivity and mechanical properties for solid−state lithium metal battery

Polyionic liquids (PILs) are considered promising candidates for next−generation solid polymer electrolytes (SPEs) because they combine the electrochemical stability of ionic liquids with the processability/flexibility of polymers. However, the practical application of PILs−based SPEs are limited by their unsatisfactory mechanical properties in parallel with their insufficient ionic conductivity. Here, a double crosslinked PIL-based SPE with an optimal balance of ionic conductivity and mechanical properties is constructed by ultraviolet (UV) initiated polymerization. Among, the ionic liquid 1−(4−vinylbenzyl)−3−butylimidazolium bis(trifluoromethanesulfonyl)imide ([VBBIM][TFSI]) as a monomer, poly(ethylene glycol) diacrylate (PEGDA) and polyhedral oligomeric sesquisiloxane (POSS) as a functional crosslinker. As expected, the synthesized PIL−based SPE (POSS-PIL-PEGDA−1, 1 wt% POSS) shows a high ionic conductivity of 1.8 × 10−4 S cm−1 (at 30 °C), a satisfactory tensile strength of 0.64 MPa, an ultrahigh thermal degradation temperature around 320 °C and a wide electrochemical stability window about 5.0 V versus Li/Li+. As a concept proof, the POSS-PIL-PEGDA−1 SPE can effectively inhibit lithium dendrites growth, and the assembled Li||LiFePO4 solid−state lithium metal battery achieves a high discharge capacity and a good cycling performance. This strategy is attractive for studying the trade−off between mechanical properties and ionic conductivity of crosslinked PIL−based SPEs.

Functionalized nano core-shell polystyrene spheres with polyionic liquids: An efficient shale stabilizer with both inhibit hydration and physical plugging

Due to shale hydration and the development of nano and micropores, wellbore instability often occurs during shale drilling, and high-performance shale stabilizers are urgently needed. A novel nano spherical shale stabilizer (i.e., PSIL) was prepared by polymerizing vinyl imidazole ionic liquid with amino group and polystyrene seed. The electron microscopy experiments and particle size analysis indicated that PSIL had a core-shell spherical structure with a particle size distribution between 200 and 300 nm. The plugging performance of PSIL was analyzed using the microporous membrane filtration experiment and pressure transfer experiment. The final filtration loss volume of 3 wt% PSIL aqueous solution was only 20 mL, and the final pressure at the end of the core was 4.0 MPa, which demonstrated that PSIL could form a dense plugging layer in the nanopore gap, thus reducing filtration loss and pressure transfer. Moreover, when the solution contained 3 wt% PSIL, the linear expansion rates of the bentonite pellets decreased from 69.1% to 38.3%, and the rolling recovery rate of shale cuttings increased from 10.5% to 41.2%. The experimental results indicated that PSIL could effectively be adsorbed onto the clay surface through electrostatic interaction and hydrogen bonds, thus reducing the repulsive force between clay interlayers and inhibiting the hydration dispersion of shales. Therefore, PSIL could play a dual role in physical plugging and inhibiting hydration, providing a new direction for developing high-performance shale inhibitors, thereby enhancing wellbore stability during drilling.

Digital light processing of customized elastic scaffolds by efficient thiol-yne crosslinking

Digital light processing (DLP) based 3D printing technology has the advantages of fast printing rate and high spatial resolution in the manufacture of tissue engineering scaffolds. However, the limited availability of printable materials for DLP technology, especially the lack of biodegradable elastomeric materials hinders the development of customized soft tissue scaffolds. Herein, liquid poly(4-methyl-ε-caprolactone) dialkynylate (PMCLDY) was prepared as a DLP printable ink based on efficient thiol-yne photocrosslinking. With the aid of photorheology and in situ FT-IR and tensile tests, an ink formulation for DLP printing was optimized as the P50 ink (PMCLDY to diluent PEGDY mass ratio of 1), which possessed fast cure rates (<15 s), low viscosity (<2 Pa·s), moderate mechanical properties (failure strain > 40 %) and maximum toughness (0.153 MJ·m−3). A commercial DLP printer equipped with the P50 ink realized 3D scaffolds models with microstructure and macroscopic shape precisely. It was demonstrated that the 3D printed scaffold with biodegradability could withstand dynamic compression cycles. Furthermore, the cytocompatibility experiments showed that the scaffold could effectively support the growth and proliferation of rat bone marrow stromal cells (BMSCs). These results demonstrate that the P50 ink is a promising material for manufacturing elastic scaffolds by DLP printing for tissue engineering applications.

The Micro-Capacitance Enhancement of Polyionic Liquids Grafted Onto Carbon Nanotubes on the Piezoelectric Properties of Poly(Vinylidene Fluoride) Films and Their Sensor Applications

The increased micro-capacitance of a poly (vinylidene fluoride) (PVDF) matrix can effectively improve the piezoelectric properties of the composite material. This work used chemically modified carbon nanotubes (CNTs) as the main reinforcement material. Atom transfer radical polymerization (ATRP) was used to graft polyionic liquids (PILs) with different hydrophilic anions to the CNTs’ surfaces. Solution casting and compressive melt molding were used to prepare the PVDF-composite piezoelectric films. Micro-capacitance formed by the PIL grafted CNTs dispersed well in the PVDF matrix, and their effects on the crystalline form and piezoelectric properties were studied. The hydrophobic hexafluorophosphate anion (-PF6 -) can significantly improve the CNTs dispersion and enhance the micro-capacitance formation in the PVDF matrix. During solution crystallization, the synergistic effect of CNTs and PIL on the PVDF and the solvent effect made the content of β phase of PVDF/CNTs@PIL-PF6 film reach 80.2%, resulting in a high dielectric constant of 188 and a piezoelectric coefficient of 36. In the process of melt crystallization, due to shear stretching and extrusion, the CNTs@PIL-PF6 had an obvious nucleation effect on the polar crystalline phase of PVDF, with a β phase content up to 99.3%, leading to the higher dielectric constant of 530 and the piezoelectric coefficient of 31. The current discovery provides a development direction for smart piezoelectric polymer matrix composites, which have great potential in preparing piezoelectric energy storage materials.

Molecular design of ultrafiltration membranes with antibacterial properties for the inactivation of antibiotic-resistant bacteria

Ultrafiltration membranes have gained significant prominence in water and wastewater treatment, holding potential for application in combating antibiotic resistance. Herein, we successfully fabricated a polyvinylidene fluoride copolymer-based ultrafiltration membrane capable of effectively removing antibiotic-resistant bacteria (ARB) from water and wastewater through the molecular design approach, incorporating polyionic liquid (PIL) via atom transfer radical polymerization. The as-prepared membrane exhibited bactericidal properties against wild-type bacteria, ARB and opportunistic pathogens, showcasing an inactivation efficiency exceeding 70 %. These properties were attributed to the increased intracellular accumulation of reactive oxygen species and enhanced membrane permeability, suggesting the involvement of oxidative stress and disruption of the cell outer membrane in bacterial cell lysis. To investigate the interaction with bacterial cells, we utilized liposome vesicles as a model, revealing that the PIL brush effectively disrupted the integrity of the bacterial cell's phospholipid bilayer through its alkyl chain. Furthermore, zeta potential measurements indicated that the role of electrostatic interactions between the imidazole ring and bacteria in bacterial inactivation mechanisms. During wastewater filtration, the PIL-M membrane demonstrated outstanding efficiency in total bacteria removal, exceeding 99.1 %. Additionally, the PIL-M membrane displayed significant bacterial inactivation capabilities against total bacteria as well as sulfamethoxazole-resistant bacteria, chloramphenicol-resistant bacteria, and tetracycline-resi8stant bacteria, achieving respective inactivation efficiencies of 91 %, 93 %, 87 %, and 85 %. These results highlight the membrane's potential in mitigating membrane fouling and inactivating antibiotic-resistant bacteria. Overall, the findings of this study suggest that the PIL-M membrane can effectively contribute to controlling bacterial resistance in water and wastewater environments.

An antistatic agent based on polyionic liquid applied to nylon 6

In order to improve the electrical conductivity of nylon 6 (PA6) and avoid misfires and explosions caused by static charge accumulation, a quaternary ammonium salt polyionic liquid (PIL) antistatic agent was synthesized in this paper. The surface resistance of PA6 was reduced to 108 Ω with the addition of 2 wt% antistatic agent, and the mechanical properties and aging resistance of the substrate were improved. Meanwhile, the morphology and crystallinity of PIL/PA6 composites were further characterized by scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD). It is worth noting that the quaternary ammonium salt polyionic liquid antistatic agent synthesized in this paper has the advantages of excellent antistatic effect, durability, low cost, and simple reaction condition, so it has a broad application prospect in the antistatic aspect of PA6.

Performance of Plastic Waste-Based Polyionic Liquid toward the Dehydration of Crude Oil Emulsions

Polyethylene terephthalate (PET) is one of the most widely used plastics in the world. Due to the large production and use of this plastic, its waste represents one of the most critical environmental problems. The purpose of this study is to convert PET waste into a valuable material. The consumed PET was transformed into a precursor to synthesize a polyionic liquid (PIL) that was used for dehydrating crude oil emulsions. To do so, the consumed PET was converted to bis(2-hydroxyethyl) terephthalate (BHET). First, BHET and tetraethylene glycol were reacted separately with thionyl chloride, obtaining the corresponding alkyl halides, bis(2-chloroethyl) terephthalate, BCET, and TEC, respectively. Next, the obtained alkyl halides, BCET and TEC, were reacted with 1,5-pentanediamine, yielding a polymer (BTP). Finally, BTP was reacted with acetic acid to produce the corresponding PIL (BTP–PIL). The structure and thermal stability of BTP–PIL were characterized using nuclear magnetic resonance spectroscopy and thermal gravimetric analysis. The dehydration performance of PIL and the original polymer was investigated using the bottle test method, including several factors such as demulsifier dose, brine content, temperature, and settling time. Results indicated that PIL achieved high performance in dehydrating crude oil emulsions.

The Detection of Anthrax Biomarker DPA by Ratiometric Fluorescence Probe of Carbon Quantum Dots and Europium Hybrid Material Based on Poly(ionic)- Liquid.

Bacillus anthracis has gained international attention as a deadly bacterium and a potentially deadly biological warfare agent. Dipicolinic acid (DPA) is the main component of the protective layer of anthracis spores, and is also an anthrax biomarker. Therefore, it is of great significance to explore an efficient and sensitive DPA detection method. Herein, a novel ratio hybrid probe (CQDs-PIL-Eu3+) was prepared by a simple one-step hydrothermal method using carbon quantum dots (CQDs) as an internal reference fluorescence and a covalent bond between CQDs and Eu3+ by using a polyionic liquid (PIL) as a bridge molecule. The ratiometric fluorescence probe was found to have the characteristics of sensitive fluorescence visual sensing in detecting DPA. The structure and the sensing properties of CQDs-PIL-Eu3+ were investigated in detail. In particular, the fluorescence intensity ratio of Eu3+ to CQDs (I616/I440) was linear with the concentration of DPA in the range of 0-50 μM, so the detection limit of the probe was as low as 32 nm, which was far lower than the DPA dose released by the number of anthrax spores in human body (60 μM) and, thus, can achieve sensitive detection. Therefore, the ratiometric fluorescence probe in this work has the characteristics of strong anti-interference, visual sensing, and high sensitivity, which provides a very promising scheme for the realization of anthrax biomarker DPA detection.

Multifunctional Janus-type self-healing MXene/polyionic liquid flexible sensor

Integration of electronic sensors with signal processing systems is important for artificial intelligence and intelligent robots. It requires mechanically robust, highly sensitive, and self-healing sensing materials that produce recognizable electrical changes in response to external stimuli. Here, we report a multifunctional Janus-type self-healing MXene/polyionic liquid-based flexible membrane for smart sensing. Flexible MXene-NH2@PIL material with self-healing capacity and high tensile properties was constructed by compounding functionalized MXene with polyionic liquid (PIL) with self-healing ability. Deposition of MXene-NH2 resulted in MXene-NH2@PIL with a unique Janus structure that exhibits a variation in the degree of hydrophilicity on both sides and a certain pH response. The material, which can be warmed to over 70 °C in 8 s, also has excellent photothermal conversion. The internal ionic and hydrogen bonding interactions ensure that it can repair damage at 60 °C. The flexible MXene-NH2@PIL sensor prepared from this material can produce significant signal changes in response to small deformations, such as knocks. The flexible MXene-NH2@PIL sensor can also be worn on the finger to detect the bending motion of the finger. This provides an idea for the preparation of self-healing flexible wearable sensors. This study explores the preparation of flexible self-healing sensors by combining the electron-conducting MXene material and ion-conducting PIL.

Revealing the role of hydrogen bond, mechanism and kinetic for hydroesterification of ethylene to methyl propionate

Hydroesterification of ethylene with carbon monoxide (CO) and methanol (MeOH) for preparing methyl propionate (MP) has stimulated researcher’s attention in recent years. Herein, the palladium-phosphine catalyzed ethylene hydroesterification with the promotion of acidic poly ionic liquids (APILs) for direct MP synthesis was developed. Series of APILs samples having different anions and acid densities were prepared and their structural properties were characterized by employing NMR, FTIR, TG and XPS. The anion type and acid density in APILs shown great influence on the catalytic performance due to the electronic effect and proton supply capacity related to Pd-H species formation. The hydrogen bond formed through the interaction between the anion of APILs and methanol could effectively promote the ethylene hydroesterification. The substrate extension experiments revealed the polarity and steric hindrance of alcohol would impact ethylene conversion. The mechanistic studies using in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) unraveled that the hydroesterification started with the activation of palladium complex to Pd-H species by CO, followed by the sequential formation of Pd-C2H4, Pd-alkyl and Pd-acyl intermediate species and consequential product MP. As a result, 94.4 % ethylene conversion could be achieved with 100 % selectivity toward MP at 80 °C and 2 MPa. No obvious deactivation behavior was observed for this kind of palladium catalyst after ten recycling experiments. The kinetic studies revealed the activation energy of ethylene hydroesterification is 59.3 kJ/mol.

Tuning the acidity of halloysite by polyionic liquid to develop an efficient catalyst for the conversion of fructose to 5-hydroxymethylfurfural

In an attempt to prepare a low-cost and efficient acidic heterogeneous catalyst for the conversion of fructose to 5-hydroxymethylfurfural under mild reaction conditions, the acidity of halloysite was improved by covalent grafting of an acidic polyionic liquid. More precisely, halloysite was first vinyl functionalized and then polymerized with vinyl imidazole and 2-acrylamido-2-methylpropanesulfonic acid. The tangling imidazole rings were further converted to acidic ionic liquids by treating them with chlorosulfuric acid. UV–Vis spectroscopy and Hammett equation confirmed that conjugation of acid polyionic liquid resulted in the increase of the acidity of halloysite. Investigation of the efficiency of the catalyst for the synthesis of 5-hydroxymethylfurfural and optimization of reaction variables showed that 5-hydroxymethylfurfural was yielded in 97.8% after 30 min under the optimum conditions, i.e. catalyst loading of 20 wt% at 70 °C. Notably, the catalyst was highly reusable and it could be reused for at least seven reaction runs with insignificant loss of its activity. Furthermore, this catalyst could also promote the conversion of sucrose and maltose to give moderate yields of 5-hydroxymethylfurfural.

Potential applications of flexible self-healing polyionic liquids as electronic skin

The flexible electronic skin with self-repairing ability has recently attracted much attention because of its great potential in many fields such as artificial limbs, robots, wearable devices and medical devices. In this work, we selected imidazole-based polyionic liquid (PVI) as the conductive component and ethyl polyacrylate (PEA) as the soft segment component to study their copolymerization. Then a large volume of bis (trifluoromethylsulfonyl) imide group (TFSI) was introduced into the copolymer through ion exchange. On this basis, by changing the feed ratio of raw materials, we obtained PVI/TFSI-co-PEA with adjustable glass transition temperature and flexibility. The Tg of TF1-3 sample is only 11.75 °C, so its tensile strain is more than 140%. Importantly, we have achieved the inherent self-healing function of materials by taking the electrostatic interaction of ion pairs in the polyionic liquid (PIL) as the driving force. The copolymer can completely repair the damage at 60 °C. In addition, the flexible segment in the copolymer is very useful for improving the ionic conductivity of PIL as an ion transfer channel. At the same time, the ionic conductivity of PIL is also enhanced by the large size of anti-anions. The ionic conductivity of TF1-3 can reach 10-6S/cm. All the above features allow this self-repairing PIL to be used as a solid electrolyte in energy equipment to improve its safety and reliability, or as a strain sensor for flexible electronic skin, which is very useful in the field of artificial intelligence.

Random ionic polymers: Salt-triggered reversible vesicular self-assembly in water

NaCl salt as an external stimulus triggers the self-assembly of ionic polymers and offers a convenient route to structuring vesicular reversible polymeric nanoparticles. In this contribution, amphiphilic random imidazolium ionic polymers are synthesized by roping the partial anion exchange and the choice of N-substituent. These polymers are evaluated for their self-assembly behavior in water, and it is strengthened by dye encapsulation application in water through self-assembly. The effects of salt and pH study demonstrated the reversibility of self-assembly. The self-assembled nano-aggregates are thermoresponsive at the upper critical solution temperature (UCST) (Cp 47 °C). The synergic balance between hydrogen bonding and ionic self-assembly is attributed to the constituents in the macromolecular structure, making these polyionic liquids (PILs) a “smart” responsive system in water upon the addition of external stimuli, such as NaCl and KPF6. This self-assembly is acquired with partial anion exchange and salt balance in the water. The unusual interfacial activity of polymer to form a regular shape eventually to surfaces organic dye molecule serving as a type of stabilizer or scavenger evidenced by nano-size and vesicular morphology analysis.

Fabrication and Toxicity Assessments of A Novel Antibacterial Polyvinyl Alcohol/Polyionic Liquid Hybrid Membrane

Poly ionic liquids (PILs) have become important choices as antibacterial agents because of their excellent biological properties and abundant species. Development of new antibacterial materials with PIL has been a feasible and popular research topic. In this paper, the Polyvinyl Alcohol/Polyionic Liquid (PVA-PIL) hybrid membranes were fabricated by vacuum drying method. Poly (1-Vinyl-3-butylimidazolium bromide) (PIL1) and poly (1-Vinyl-3-butylimidazolium bromide)-poly (butyl acrylate) (PIL2) were selected and tested as the main components of bacteriostatic agents. The antibacterial properties of the PVA-PIL hybrid membranes against bacteria E. coli and S. aureus were tested by the disc method. Meanwhile, the cytotoxicities of hybrid membranes were evaluated against mouse fibroblast (L929) by fluorescent staining experiment. M2 showed excellent antibacterial properties which could not be found on M3. Furthermore, all PVA-PIL membranes exhibited favorable cytocompatibilities. These properties make M2 a possible candidate for wound dressing.