Ether Imide Research Articles

Enhanced Thermal Conductivity in Poly(ether imide)-Based Composites via Constructing Microscopic Segregated Networks with Ag-Bridged Graphite Nanoplatelets

Enhanced Thermal Conductivity in Poly(ether imide)-Based Composites via Constructing Microscopic Segregated Networks with Ag-Bridged Graphite Nanoplatelets

Spleen Targeting Nucleic Acid Delivery Vector Based on Metal-Organic Frameworks.

Nucleic acids have attracted increasing attention as drugs due to their fascinating advantages, such as long-term efficacy and ease of preparation compared to proteins. The nucleic acid therapy relies heavily on delivery vectors, which can prevent the degradation of nucleic acids while assisting them in cellular internalization. However, commonly used nonviral vector liposomes easily accumulate in the liver, which can limit their application in extrahepatic diseases. Herein, a potential spleen targeting vector for nucleic acids is developed based on the metal-organic frameworks. The plasmids are encapsulated inside the nanoscale zeolitic imidazolate framework (ZIF) via coprecipitation. The co-encapsulation of the cationic polymer poly(ether imide) (PEI) and the stabilizer polyvinylpyrrolidone (PVP) can significantly improve particle dispersion and stability. The prepared nanoparticles allow efficient transfection in vitro, mainly through clathrin-mediated and caveolae-mediated endocytosis. The biodistribution in mice shows that 46% of the nanoparticles accumulate in the spleen, which is much higher than that of the liposomes. The vector can successfully deliver plasmids to extrahepatic organs for protein synthesis and even induce an immune response. The elaborate ZIF-based nanoparticle may offer a new route for extrahepatic, especially spleen targeting delivery for the nucleic acids.

Investigating the tensile properties and crystallinity of 3D-printed poly (ether ether ketone)/poly (ether imide) [PEEK/PEI] blend in the Z-direction by fused filament fabrication

Investigating the tensile properties and crystallinity of 3D-printed poly (ether ether ketone)/poly (ether imide) [PEEK/PEI] blend in the Z-direction by fused filament fabrication

Fabrication and manipulation of hierarchically porous PEEK membranes based on crystallization‐induced phase segregation and sea‐island structures

AbstractPoly ether ether ketone (PEEK) is a premier engineering plastic, which has gained considerable attention in recent years. Our prior research investigated crystallization template techniques and pore formation mechanisms within the PEEK/poly (ether imide) system, paving the way for the development of hierarchically porous membranes (HPMs). Compared to single‐porous membranes, HPMs demonstrate enhanced flux and high mass transfer efficiency simultaneously, effectively mitigating the trade‐off effects. In this study, we focused on fabricating PEEK HPMs through precise manipulation of a polymer ternary blend system. The meticulous tuning enables intricate control of the hierarchical pore morphology of PEEK at two distinct scales. The finite element simulations not only underscored the crucial role of hierarchical pores in bolstering separation efficiency, but also exhibited strong concordance with the experimental findings. This study provides guidance for future optimization of HPMs with superior separation performance.

Liquid-Phase Adsorption of Dimethyl Methylphosphonate on Poly(ether imide) and its Metal Hydroxide-Integrated Composites

Liquid-Phase Adsorption of Dimethyl Methylphosphonate on Poly(ether imide) and its Metal Hydroxide-Integrated Composites

Constructing Deep Traps to Achieve Excellent Dielectric Properties in Crystal-Based HfO2/PEI Nanocomposite Films with Ultralow Filler Loadings.

Mixing fillers featured with wide band gaps in polymers can effectively meet the requirement of higher energy storage densities. However, the fundamental relationship between the crystal structures of fillers and the dielectric properties of the corresponding nanocomposites is still unclear. Accordingly, we introduced ultralow contents of the synthesized cubic Hafnium dioxide (c-HfO2) or monoclinic Hafnium dioxide (m-HfO2) as deep traps into poly(ether imide) (PEI) to explore their effects on dielectric properties and the charge-blocking mechanism. m-HfO2/PEI showed better charge trapping due to the higher electron affinity and deeper trap energy. At room temperature, the 0.4 vol % m-HfO2/PEI maintains an ultralow dielectric loss of 0.008 while obtaining a dielectric constant twice that of pure PEI at 1 kHz, simultaneously outperforming in terms of leakage current density, breakdown strength (452 kV mm-1), discharge energy density (Ud, 5.03 J cm-3), charge-discharge efficiency (η, 92%), and dielectric thermal stability. At 125 °C, it exhibits a considerable Ud of 2.48 J cm-3 and a high η of 85% at 300 kV mm-1, surpassing the properties of pure PEI. This promising work opens up a new path for studying HfO2-derived dielectrics with unique crystal structures.

Simultaneous Inhibition of Conduction Loss and Enhancement of Polarization Intensity of Polyetherimide Dielectrics for High-Temperature Capacitive Energy Storage.

Polymer dielectrics with excellent high-temperature capacitive energy storage performance are in urgent demand for modern power electronic devices and high-voltage electrical systems. Nevertheless, the energy storage capability usually degrades dramatically at increased temperatures, owing to the exponentially increased conduction loss. Herein, a trace of commercially available aluminum nitride (AlN) nanoparticles is incorporated into the poly(ether imide) (PEI) matrix to inhibit the conduction loss. The nanostructured AlN component with a large specific surface area can provide abundant sites for the collision of carriers. More importantly, the generated new trap energy levels can immobilize the carriers, accordingly contributing to the reduction in leakage current. From this, the discharged energy density at 150 °C of PEI composites increases by 82.13% from 2.63 J/cm3 for pristine PEI to 4.79 J/cm3 for PEI composites. This work establishes a facile approach to enhancing the high-temperature capacitive performance of polymer dielectrics.

Synergistic Toughening of Epoxy through Layered Poly(ether imide) with Dual-Scale Morphologies.

Toughness of epoxies is commonly improved by adding thermoplastic phases, which is achieved through dissolution and phase separation at the microscale. However, little is known about the synergistic effects of toughening phases on multiple scales. Therefore, here, we study the toughening of epoxies with layered poly(ether imide) (PEI) structures at the meso- to macroscale combined with gradient morphologies at the microscale originating from reaction-induced phase separation. Characteristic features of the gradient morphology were controlled by the curing temperature (120-200 °C), while the layered macro structure originates from facile scaffold manufacturing techniques with varying poly(ether imide) layer thicknesses (50-120 μm). The fracture toughness of the modified epoxy system is investigated as a function of varying cure temperature (120-200 °C) and PEI film thickness (50-120 μm). Interestingly, the result shows that the fracture toughness of modified epoxy was mainly controlled by the macroscopic feature, being the final PEI layer thickness, i.e., film thickness remaining after partial dissolution and curing. Remarkably, as the PEI layer thickness exceeds the plastic zone around the crack tip, around 62 μm, the fracture toughness of the dual scale morphology exceeds the property of bulk PEI in addition to a 3 times increase in the property of pure epoxy. On the other hand, when the final PEI thickness was smaller than 62 μm, the fracture toughness of the modified epoxy was lower than pure PEI but still higher than pure epoxy (1.5-2 times) and "bulk toughened" system with the same volume percentage, which indicates the governing mechanism relating to microscale interphase morphology. Interestingly, decreasing the gradient microscale interphase morphology can be used to trigger an alternative failure mode with a higher crack tortuosity. By combining facile scaffold assemblies with reaction-induced phase separation, dual-scale morphologies can be tailored over a wide range, leading to intricate control of fracture mechanisms with a hybrid material exceeding the toughness of the tougher phase.

Near-Infrared Light-Controlled MicroRNA-21-Loaded Upconversion Nanoparticles to Promote Bone Formation in the Midpalatal Suture.

Rapid maxillary expansion (RME) is a common therapy for maxillary transverse deficiency. However, relapses after RME usually occur because of insufficient bone formation. MicroRNA-21 (miR-21) was reported as an important post-transcriptional modulator for osteogenesis. Herein, a photocontrolled miR-21 (PC-miR-21)-loaded nanosystem using upconversion nanoparticles (UCNPs) modified with poly(ether imide) (PEI), i.e., UCNPs@PEI@PC-miR-21, was constructed to promote bone formation in the midpalatal suture. UCNPs@PEI was constructed as the light transducer and delivery carrier. The UCNPs@PEI@PC-miR-21 nanocomplexes have good aqueous dispersibility and biocompatibility. The in vitro cell experiment suggested that UCNPs@PEI could protect PC-miR-21 from biodegradation and release PC-miR-21 into the cytoplasm under near-infrared light (NIR) irradiation. Furthermore, UCNPs@PEI@PC-miR-21 upregulated the expression of the osteogenic key markers, ALP, RUNX2, and COL1A1, at the levels of both genes and proteins. Besides, the results of the in vivo RME mice models further corroborated that photocontrollable UCNPs@PEI@PC-miR-21 accelerated bone formation with upregulating osteogenic markers of ALP, RUNX2, and osteoprotegerin and inducing fewer osteoclasts formation. In conclusion, UCNPs@PEI@PC-miR-21 nanoparticles with a NIR light could facilitate the remote and precise delivery of exogenous miR-21 to the midpalatal suture to promote bone formation during RME. This work represents a cutting-edge approach of gene therapy to promote osteogenesis in the midpalatal suture during RME and provides a frontier scientific basis for later clinical treatment.

Largely Enhanced Surface Flashover Voltage of Poly(ether Imide) by Scalable and Durable ZnO Coating: A Gift from In Situ Growth.

Dielectric materials with high surface electric insulation strength are in great demand in a high-power space solar cell array (SSCA). A moderately conductive surface is favorable to inhibit charge accumulation and mitigate electric field distortion, thus improving the surface flashover voltage. Although numerous modification methods have been proposed to achieve this goal, the facile, efficient, scalable, and environmentally friendly modification strategy remains a critical challenge to date. Considering the excellent charge modulation ability of ZnO and its mild preparation conditions, a facile and economical hydrothermal strategy was proposed to fabricate in situ a durable poly(ether imide)/zinc oxide (PEI/ZnO) coating with a high charge decay rate. The blooming flower-like ZnO in the coating is proved to play a key role in enhancing lateral charge dissipation on the surface of PEI, thereby suppressing surface charge accumulation. It was also shown that the shielding effect of ZnO on high-energy photons during flashover and the catalytic effect of Zn2+ on PEI molecular chains during hydrothermal treatment had a facilitating and suppressing effect on outgassing, respectively, and consequently affected the flashover. Excitingly, the synergistic effects of both accelerated charge dissipation and suppressed outgassing helped to improve the flashover voltage of PEI by up to 36.7%. The strategy selected here is efficient, scalable, and facile, and the coating is durable, which makes sense for commercial promotion.

Enhancing High-Temperature Energy Storage Performance of PEI-Based Dielectrics by Incorporating ZIF-67 with a Narrow Bandgap.

Polymer dielectrics are crucial for use in electrostatic capacitors, owing to their high voltage resistance, high energy storage density, and ultrahigh reliability. Furthermore, high-temperature-resistant polymer dielectrics are applied in various emerging fields. Herein, poly(ether imide) (PEI)-based polymer dielectrics prepared by adding a low loading of dimethylimidazolium cobalt (ZIF-67) with a narrow bandgaps are investigated. The results show that the composites exhibit considerably increased Young's modulus, suppressed conductivity loss, and improved breakdown strength compared with pure PEI. Consequently, a stable energy storage performance is realized for ZIF-67/PEI composites. Particularly, at 150 °C, 1 wt % ZIF-67/PEI composite affords an excellent energy storage density of 4.59 J/cm3 with a discharge energy efficiency of 80.6%, exhibiting a considerable increase compared with the values obtained for PEI (2.58 J/cm3 with a discharge energy efficiency of 68.8%). The results of this study reveal a feasible pathway to design polymer dielectrics with the potential for use in capacitive applications in harsh environments.

Surface Treatment of Polymer Membranes for Effective Biofouling Control.

Membrane biofouling is the consequence of the deposition of microorganisms on polymer membrane surfaces. Polymeric membranes have garnered more attention for filtering and purifying water because of their ease of handling, low cost, effortless surface modification, and mechanical, chemical, and thermal properties. The sizes of the pores in the membranes enable micro- and nanofiltration, ultrafiltration, and reverse osmosis. Commonly used polymers for water filter membranes are polyvinyl chloride (PVA), polyvinylidene fluoride (PVDF), polyamide (PA), polyethylene glycol (PEG), polyethersulfone (PES), polyimide (PI), polyacrylonitrile (PAN), polyvinyl alcohol (PA), poly (methacrylic acid) (PMAA), polyaniline nanoparticles (PANI), poly (arylene ether ketone) (PAEK), polyvinylidene fluoride polysulfone (PSF), poly (ether imide) (PEI), etc. However, these polymer membranes are often susceptible to biofouling because of inorganic, organic, and microbial fouling, which deteriorates the membranes and minimizes their lives, and increases operating costs. Biofouling infection on polymer membranes is responsible for many chronic diseases in humans. This contamination cannot be eliminated by periodic pre- or post-treatment processes using biocides and other chemicals. For this reason, it is imperative to modify polymer membranes by surface treatments to enhance their efficiency and longevity. The main objective of this manuscript is to discuss application-oriented approaches to control biofouling on polymer membranes using various surface treatment methods, including nanomaterials and fouling characterizations utilizing advanced microscopy and spectroscopy techniques.

Interfacial interaction of controlled poly(ether-imide) (PEI) - titanium dioxide-based nanocomposites

The nanocomposites were produced using a melt-blending process and poly (ether imide) (PEI) reinforced with bioactive titanium dioxide (TiO2) nanoparticles. Fourier Transformed Infrared Spectroscopy (FTIR), Microstructural analysis, Differential Scanning Calorimetric (DSC) of the generated interfacial interaction materials is exploited. The prominent peaks in FTIR measurement are found to be sensitive to TiO2 content. The peaks shift towards higher wavelength as a consequence of TiO2 addition. Polymer matrix and filler in the FTIR spectrum have a significant hydrogen bonding coupling. The uniform dispersion of TiO2 nanoparticles within the polymer was studied without surface treatment or polymer functionalization. It has been observed that with increasing TiO2 concentration, the matrix's crystallisation rate was altered from promotion to retardation, while its crystalline structure remained unaffected. TiO2 addition gradually lowers the glass transition temperature (Tg) of poly (ether imide) composite. The polymer matrix was concurrently made stiffer, stronger, and tougher by the nanoparticles, and the best characteristics were attained at 5.0 wt% of TiO2. Even though the nanocomposites had improved thermal stability and glass transition temperatures, they also showed less water absorption. The analyses are utilised to determine the type of nanoparticle and the consistency of the composite material's loading.

Phase-inversion Induced Co-assembly of Poly(ether imide)/Aramid Nanofibrillar Composite Separators for High-speed Lithium-metal Batteries

Li-metal batteries with high energy capacities and charging rates remain far from practical implementation, mainly due to uncontrollable Li dendrite growth. Herein, we report poly(ether imide)/aramid nanofibrillar (PEI/ANF) composite separators fabricated using the phase-inversion induced co-assembly method, which can effectively suppress dendrite growth. Phase-inversion processes facilitated the co-assembly of PEI agglomerates and self-assembled ANFs into composite nanofibrillar network structures to achieve ultrahigh bulk porosity (>95%) with controlled surface porous structures. Additionally, the unique shapes of the undulated PEI sheaths over the ANF nanofibrils promoted a high surface area of the exposed ether (C−O−C) and carbonyl (C=O) functionality with high affinity to carbonate electrolytes and Li+ and PF6− ions. The resultant films presented enhanced ionic conductivities of up to 3.30 mS cm−1, and a maximum Li+ ion transference number of 0.84. These characteristics promote the formation of compact and stable fluorine-rich solid-electrolyte interphase (SEI) layers on the Li-metal anodes and effectively suppressed Li dendrite growth under extremely high charge/discharge conditions. The Li/Li symmetric cells exhibited stable operation up to 1500 cycles with a high current density of 10 mA cm–2. Moreover, LiFePO4/Li full cells with a high cathode mass loading (6–7 mg cm–2) exhibited a capacity retention of 74.3% after 500 cycles at 10 C-rate (12.0 mA cm−2). The suggested fabrication method would serve as a novel and promising approach for separators in next-generation batteries with high energy density and high C-rate capability.

Comprehensive investigations of trans-cis-trans isomerization in the solid state for azo polyimides

This work describes the thermal cis-trans isomerization in the solid-state for poly(ether imide)s and poly(ester imide)s with azobenzene or azo pyridine moieties. The cis-trans relaxation was monitored for covalently functionalized polyimides (main-chain, side-chain, „T-type”) and “guest-host” azo systems. The obtained results from the investigations allow us to formulate some general relationships between material aspects such as polyimide structure, its molar mass, the content of azo dye, the value of d-spacing, the thickness of polymer film, and thermal cis-trans isomerization. The reversibility of the trans-cis-trans reaction was studied in 10 subsequent cycles and 100 cycles for the selected polymers. Studies of the reversibility of the trans-cis-trans reaction were realized by irradiation using two wavelengths of radiation λ = 365 nm (P = 2.9 W) and λ = 460 nm (P = 850 mW). To the best of our knowledge, this is the first article that comprehensively presents solid-state cis-trans isomerization for azo polyimides.

More than Just a Binder: Versatile Block Copolymer Enhances the Electrochemical Performance of a Nickel-Rich Cathode

Nickel-rich layered cathodes (for example, NCM811) hold great promise for practical applications in high-energy density lithium-ion battery technology. However, a nickel-rich cathode has poor cyclic stability because of the structure degradation induced by repeated cycles and excessive formation of thick cathode–electrolyte interface (CEI) layers. Poly(vinylidene difluoride) (PVDF) is a typical binder used to form a positive electrode, which nevertheless lacks the functionality to suppress structure degradation and control CEI layer formation. A new concept is proposed in this work to use a multi-functional block copolymer of poly(ether imide)-block-poly(dimethyl siloxane) (PEI-b-PDMS; abbreviated as PEMS) as the binder for the nickel-rich cathode. Unlike the conventional PVDF binder, the PEMS binder is capable of inhibiting crack formation within the NCM811 particles to retard structure degradation over cycles because of its elastomeric feature. The PEMS binder also enables tuning the composition of the CEI layer and inhibits the formation of overly thick CEI layers because the carbonate solvent molecules are excluded from the solvation sheath by the PEMS binder. Enhanced electrolyte affinity is exhibited by the electrode with the PEMS binder as evidenced by the contact angle measurement. Improved carbon black dispersion within the electrode is achieved by the PEMS binder because the PEI aromatic chain has strong affinity toward the carbon black particles. Both the cycling and rate performance of the NCM811 cathode is improved with the PEMS binder compared to the PVDF binder. In detail, the capacity retention is increased from 63.9 to 80.6% after 200 cycles at 0.5 C (1 C = 205 mAh g–1) when the PVDF binder is replaced by the PEMS binder. The rate performance at current densities of 2 and 5 C is increased significantly due to enhanced electrochemical kinetics.

Thermal treatment effect on electrochemical properties of silicon alloy anodes with poly(ether imide) binder for lithium-ion batteries

The development of silicon-based anodes with high capacity and good cycling stability for next-generation Li+ batteries (LIBs) is a very challenging task due to the large volume expansion of the electrodes during repeated cycling, which leads to fading in capacity. In this study, the electrochemical performance of Si alloy-based anodes with poly (ether imide) (PEI) binder is evaluated after thermal treatment at various temperatures. The systematic study revealed that the thermal treatment of the anodes with PEI binder at above 500 °C results in the partial carbonization of the PEI and remarkably enhances the electrochemical performance, such as cycle life and high rate capabilities. The partially carbonized PEI acts as both a binder and conductive additive for the Si-alloy anodes. This superior electrochemical performance is attributed to the strong adhesion of the partially carbonized PEI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. The partial carbonization strategy can be readily scaled up due to the facile heat treatment process, offering a new approach for developing next-generation high-capacity batteries.

Organosoluble and colorless fluorinated poly(ether imide)s containing a bulky fluorene bis(ether anhydride) and various trifluoromethyl-substituted aromatic bis(ether amine)s: synthesis and characterization

Organosoluble and colorless fluorinated poly(ether imide)s containing a bulky fluorene bis(ether anhydride) and various trifluoromethyl-substituted aromatic bis(ether amine)s: synthesis and characterization

Space Charge Contributions to the Dielectric Response and Breakdown Strength of High-Temperature Poly(ether imide)/Polyimide Blends

Dielectric properties of poly(ether imide)/polyimide blends, prepared by the solution casting method, were measured over broad frequency and temperature ranges and compared to the response of pristine polymers. While the intrinsic dielectric permittivity only slightly decreases, the electrical conductivity of blends is approximately 40% lower than the conductivity of poly(ether imide) and polyimide. A detailed low-frequency investigation revealed a significant reduction of accumulated space charges in blend systems and thus confirmed that the enhancement of their breakdown strength occurs due to strong electrostatic interactions between the differently charged phenyl groups in poly(ether imide) and polyimide chains. Because a notable influence of absorbed water on the overall dielectric response was found, particularly in the presence of γ relaxation, the impact of high-temperature annealing on the dielectric breakdown strength was also examined.

Thermoplastic composite connecting rods

Engineering carbon fiber thermoplastics have been used in the development and optimization of composite connecting rod(s) with design requirement of bearing 14,000 N and 1 mm maximum deflection. The studies featured engineering thermoplastics- 30 wt percent carbon fiber poly ether ether ketone (C-PEEK) long fiber thermoplastics (LFT) injection over molded in conjunction with 70 wt percent carbon/polyphenylene sulfide (C-PPS) and carbon/poly ether imide (C-PEI) tapes. Over molding of thermoplastic tapes has been investigated in terms of number of tape winding around the small and big end, and different winding patterns within the connecting rod geometry. The design was progressively optimized for the geometry of the connecting rod, i.e., increasing the wall thickness of the small end and width of the center section. The effect of over molded metal bushing with C/PEEK LFT at the bearing surfaces was also investigated. The material and geometry optimization successfully met 14,000 N while several design iterations were necessary to meet the 1 mm deflection limit constraint. Finite element analysis (FEA) was adopted to optimize the increase of the width of the center section width and wall thickness of the small end. The optimized composite connecting rod was estimated to be 78% lighter than the steel incumbent.