Nonwoven Membrane Research Articles

Electrospun Polyphenylquinoxaline Ultraline Non-woven Fibrous Membranes with Excellent Thermal and Alkaline Resistance: Preparation and Characterization

A series of polyphenylquinoxaline (PPQ) ultrafine non-woven fibrous membranes have been first successfully prepared via the electrospinning procedure with the soluble PPQ solutions as the starting materials. For this purpose, various organo-soluble PPQ resins were synthesized via the one-step high temperature polycondensation procedure from the aromatic ether-bridged bis(α-diketone) and bis(o-diamine) monomers. Flexible ether linkages and pendant bulky phenyl substituents endowed the PPQ resins good solubility in polar aprotic solvents. The high-molecular-weight PPQ resins were dissolved in N-methyl-2-pyrrolidone (NMP) to afford the PPQ electrospinning solution except PPQ-Ia derived from 4,4′-oxydibenzil (ODB) and 3,3′-diaminobenzidine (DAB) due to the limited solubility in the solvent. All the derived PPQ ultrafine non-woven fibrous membranes maintained good structure integrity after hydrolysis aging either at room temperature (25 °C) for 72 h or at refluxing temperature (100 °C) for 24 h in an aqueous sodium hydroxide (NaOH) solution at a solid content of 20 wt%. Comparatively, the polyimide (PI) reference electrospun membrane (PI-ref) derived from 1,2,4,5-pyrromellitic anhydride (PMDA) and 4,4′-oxydianiline (ODA) lost its original structure only after boiling in the same NaOH solution within 3 h. In addition, the developed PPQ ultrafine non-woven fibrous membranes exhibited good thermal stability with the 5 % weight loss temperatures (T5%) higher than 555.0 °C in nitrogen and glass transition temperatures (Tg) in the range of 248.1–266.1 °C, respectively.

MOF-Derived Co3O4 Polyhedrons as Efficient Polysulfides Barrier on Polyimide Separators for High Temperature Lithium-sulfur Batteries.

The incorporation of highly polarized inorganic compounds in functional separators is expected to alleviate the high temperature safety- and performance-related issues for promising lithium–sulfur batteries. In this work, a unique Co3O4 polyhedral coating on thermal-stable polyimide (PI) separators was developed by a simple one-step low-temperature calcination method utilizing metal-organic framework (MOF) of Co-based zeolitic-imidazolate frameworks (ZIF-Co) precursors. The unique Co3O4 polyhedral structures possess several structural merits including small primary particle size, large pore size, rich grain boundary, and high ionic conductivity, which endow the ability to adequately adsorb dissolved polysulfides. The flexible-rigid lithium-lanthanum-zirconium oxide-poly(ethylene oxide) (LLZO-PEO) coating has been designed on another side of the polyimide non-woven membranes to inhibit the growth of lithium dendrites. As a result, the as-fabricated Co3O4/polyimide/LLZO-PEO (Co3O4/PI/LLZO) composite separators displayed fair dimensional stability, good mechanical strength, flame retardant properties, and excellent ionic conductivity. More encouragingly, the separator coating of Co3O4 polyhedrons endows Li–S cells with unprecedented high temperature properties (tested at 80 °C), including rate performance 620 mAh g−1 at 4.0 C and cycling stability of 800 mAh g−1 after 200 cycles—much better than the state-of-the-art results. This work will encourage more research on the separator engineering for high temperature operation.

Piezoelectric polymer membranes with thin antibacterial coating for the regeneration of oral mucosa

Herein, we have fabricated non-woven piezoelectric polymer membranes from a copolymer of vinylidene fluoride with tetrafluoroethylene by electrospinning for the regeneration of oral mucosa. In endeavor to make the antibacterial membranes, we have deposited a thin copper coating on the outer surface of the material via magnetron sputtering. The study of the physicochemical properties of membranes over the course of various plasma treatment times demonstrated that while coating deposition does not affect material physico-chemical properties, it allows making the membranes antibacterial. In vivo studies have shown that non-woven piezoelectric polymer membranes contribute to the oral mucosa regeneration and the copper antibacterial coating accelerates this process largely.

Organic Liquid Impregnation Behavior into Nanofibrous Membranes: Quantitative Analysis of the Effects of Structural Parameters.

This paper reports the effects of structural parameters on organic liquid impregnation behavior into nanofibrous (NF) polymer membranes. The NF membranes were prepared from organic liquidphilic polymers, poly(amide-imide)s (PAIs), by electrospinning. The impregnation velocity of the organic liquid, ethylmethylcarbonate, into the as-spun PAI NF membranes with diameters ranging from 400 to 900 nm was approximately 10–20 times higher than that into commercial cellulose nonwoven membranes. Our theoretical analyses based on the Kozeny–Carman equation and multivariate statistics clearly indicate that in addition to the porosity of the membranes, the variation in fiber diameter as well as the average fiber diameter is a crucial factor for controlling the liquid impregnation behavior.

Fabrication of epoxy resin reinforced polyimide (PI) nanofibrous membrane

Electrospinning is an emerging technique to fabricate nanofibrous nonwoven membranes, but the weak mechanical strength of electrospun products is blocking their applications. In this research, the PI nanofibrous nonwoven membranes were afforded via electrospinning and reinforced by facilely dipping into a diluted epoxy resin solution. There was fusion of fibers at the points of contact or cross among them, which provided about 4 times stronger strength than that of pristine PI ones and higher elongation at break. Furthermore, the epoxy reinforced PI membrane was not fuzzing and had strong adhesion to substrates. They exhibited good filtration efficiency and did not increase pressure-drop overwhelmingly although the average pore size reduced. This research suggested a feasible strategy to fabricate epoxy resin reinforced nanofibrous membranes, which would be promising applications in air filtration, battery’s separator, water treatment etc.

Stabilization of zero valent iron (Fe0) on plasma/dendrimer functionalized polyester fabrics for Fenton-like removal of hazardous water pollutants

This study reports the synthesis, immobilization and stabilization of multiscale zero valent iron (Fe0 = ZVI) particles on fibrous polyester (PET) nonwoven membrane for heterogeneous Fenton-like removal of hazardous pollutants in water. Activation of PET fiber surface by air atmospheric plasma with or without a consecutive grafting of hyperbranched poly-(ethylene glycol)-pseudo generation 5 dendrimer having hydroxyl (-OH) end group functionality created polar reactive functional groups allowing immobilization and stabilization of ZVI particles. Synthesis of ZVI was carried out through chemical reduction of ferric ions, either through a single step in-situ, or a two-step ex-situ reduction-immobilization method. The nonwovens were characterized using wettability, Fourier transform infrared spectroscopy (FTIR), optical microscopy, scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). Results confirmed the formation and immobilization of nano to sub-micronic multi-scale ZVI particles. The particle size, distribution and stability of ZVI were found to be influenced by the methods of ZVI synthesis and PET surface activation used. The ZVI particles initially formed, quasi-instantaneously turned to yellowish brown indicating the formation of oxide layer, except in the case of dendrimer grafted PET, where higher content (22.30%) and stability of ZVI was detected. All ZVI immobilized nonwovens exhibited high effectiveness towards Fenton-like degradation of malachite green dye (20 ppm), with fastest color removal (98% in 20 min) achieved by dendrimer/ex-situ nonwoven. This nonwoven could be used up to eight repeated cycles providing low TDS (52 ppm) and high COD reduction (66.23%). Combined use of eco-friendly plasma and dendrimer grafting, provides efficient fibrous textile base heterogeneous catalysis.

Robust Polyimide Nanofibrous Membrane with Bonding Microstructures Fabricated via Dipping Process for Lithium‐Ion Battery Separators

Herein, an innovative polyimide (PI) nanofibrous membrane with unique bonding microstructures is fabricated for lithium‐ion battery (LIB) separator application via an elaborately designed dipping method using polyamic acid (PAA) glue as the joint binder. Furthermore, the bonding degree can be easily adjusted by simply varying the concentration of PAA glue. The introduction of bonding microstructures into the PI nanofibrous nonwoven membrane leads to the formation of tough 3D networks between PI nanofibers and turns the loose–weak nonwoven membrane to a compact–robust fabric membrane. The tensile strength of the PI nanofibrous membrane is consequently promoted from 5 to 36 MPa, which greatly improves the feasibility of the membrane for the LIB winding process and the safety of the LIB during long‐term running. The cells using the bonded PI nanofibrous separators exhibit an excellent cycling stability and rate capability, manifesting 80.3% capacity retention at 5 C (i.e., 128.5 mAh g−1) and can run stably at a high temperature of 120 °C. Herein, the prepared PI nanofibrous membranes with such bonding microstructures are demonstrated, which have the potential to be advanced separators for secure and high‐power LIBs.

Bifunctional perovskite electrocatalyst and PVDF/PET/PVDF separator integrated split test cell for high performance Li-O2 battery

In this work, we have studied the electrochemical performance of split test cell based Li-O2 battery using PVDF/PET/PVDF nanofiber non-woven membrane and La0.5Ce0.5Fe0.5Mn0.5O3 perovskite (denoted as LCFMO) air cathode. The LCFMO air cathode is prepared by a simple wet chemical co-precipitation method and the PVDF/PET/PVDF nanofiber separator is synthesized by an electrospinning method. The as-prepared air cathode and PVDF/PET/PVDF separators are assembled in Li-O2 cell and their charge-discharge profile is evaluated at the potential window of 2–4.5 V at 100 mA g−1 with a limited capacity range of 300, 500 and 1000 mAh g−1. The result certified that the LCFMO-(Urea) catalyst based Li-O2 battery with PVDF/PET/PVDF separator showed an excellent cycling stability over 263, 147 and 120 cycles, respectively. This is due to the excellent bifunctional activity of LCFMO catalyst and high ionic transport properties of PVDF/PET/PVDF membrane. Also, the use of LiI redox mediator can effectively reduce the both charge and discharge overpotential of our Li-O2 battery system. The optimal pore size, higher porosity and good ionic conductivity of the PVDF/PET/PVDF membrane is also an essential factor for the enhanced performance of Li-O2 battery. In addition, AC impedance study evidenced that the Li-O2 battery shows much lower interfacial charge transfer resistance (i.e., lower Rct), which indicates the good electrochemical properties of our proposed materials.

Efficient oil/water separation by a durable underwater superoleophobic mesh membrane with TiO2 coating via biomineralization

In this work, a novel and facile method was used to coat a uniform and conformal TiO2 film on a stainless steel mesh via polyethylenimine-catalyzed biomineralization of titanium bis(ammonium lactato)dihydroxide at neutral pH, ambient temperature and pressure. The fabricated mesh showed excellent superhydrophilicity and underwater superoleophobicity. It separated immiscible oil/water mixtures by gravity at a high flux (∼3 × 104 L m−2 h−1), high separation efficiency (∼99.999%), and exhibited excellent anti-oil-fouling ability. The mesh also demonstrated great durability: (1) it had outstanding stability in 1 M NaCl, 0.1 M HCl, 0.1 M NaOH solutions, and absolute ethanol; (2) it maintained underwater superoleophobicity in solutions of pH from 1 to 13 and saturated NaCl solutions; and (3) the separation efficiency was retained after high temperature treatment and mechanical wear tests (sonication, abrasion and crumpling). The biomineralization coating method was also applied on other substrates (nonwoven mesh, filter paper and PVDF membrane), which also showed good capability for oil/water separation. Therefore, this new environmentally benign approach of preparing superwetting surfaces provides a durable and sustainable solution to the treatment of oily wastewater.

Removal of nuclides and boric acid from simulated radioactive wastewater by forward osmosis

In this paper, the removal of nuclides and boric acid from the simulated borate-containing radioactive wastewater was studied using forward osmosis (FO) process. The effect of membrane materials and their orientation, as well as borate concentration on the flux and retentions of nuclides and boric acid was determined. The results indicated that cellulose triacetate with embedded polyester screen support (CTA-ES) membrane had highest Co2+ retention (99.62–99.69%) and Sr2+ retention (96.90–97.85%) when boric acid concentration increased from 0 to 2400 mg L−1 and the active layer facing feed solution (AL-FS) mode was used. Cellulose triacetate with a cast nonwoven support (CTA-NW) and CTA-ES membranes had equivalently high Cs+ retention (∼95%). Thin-film composite with embedded polyester screen support (TFC-ES) membrane had lowest Cs+ retention (below 40%). For both CTA membranes at AL-FS mode, the nuclide retentions did not change obviously with borate concentration. However, the nuclide retention for TFC-ES membrane was affected by borate concentration. Borate retention was lower than 37% for three membranes. For both CTA membranes, borate concentration had no obvious influence on the trans-membrane osmotic pressure, water flux and reverse NaCl flux. CTA-ES membrane has potential for the treatment of borate-containing radioactive wastewater due to its highest nuclide retention, boric acid flux and water flux.

Morphology of Electrospun Non-Woven Membranes of Poly(vinylidene fluoride-co-hexafluoropropylene): Porous and Fibers

In this paper, poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers membranes were fabricated by facile single-capillary electrospinning at different times of production. The materials were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA), mercury porosity intrusion (MIP), Tensile tests, capillary flow porosity (CFP) and, BET surface by nitrogen adsorption-desorption. The membranes were fabricated varying the fibers density, the thickness and the morphology. The samples presented a good fiber diameter distribution and an average diameter of 321 nm. AFM results showed high porosity (82.7-87.5 %), a high contact angle of 159.2°, mean pore size of 0.637 μm and hydrophobicity of the membranes. A low value of permeate pure water flux, 5.2 %, was observed for the densest fabricated membrane. The porosity of fibers diameters was similar for all samples, which is an important parameter as they can be potential materials for membrane distillation process.

Engineering silver‐zwitterionic composite nanofiber membrane for bacterial fouling resistance

ABSTRACTBacterial attachment and fouling compromise material performance in applications ranging from marine equipment and biomedical devices to water treatment systems. For membrane‐based water treatment systems, bacterial attachment and biofilm formation decrease water purification efficiency and reduces mechanical durability of the membranes. In this work, we present a concurrent electrospinning and copolymerization approach to engineer composite nanofiber membranes comprising of silver nanoparticle containing poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP‐Ag) nanofibers and [copolymerized zwitterionic sulfobetaine methacrylate‐methacryl polyhedral oligomeric silsesquioxane]‐poly(methyl methacrylate) nanofibers. We characterized the surface morphology, topography, material chemistry, and wettability of the nanofiber membranes with scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and contact angle measurements. We then challenged these nonwoven membranes with two model microbes, Gram‐negativePseudomonas aeruginosaand Gram‐positiveStaphylococcus aureus, and found that the silver‐zwitterionic composite nanofiber membrane exhibited superior bacterial fouling resistance by reducing >90% of bacterial attachment when compared to neat PVDF‐HFP and PVDF‐HFP‐Ag nanofiber membranes. This study demonstrates that concurrent electrospinning enables free‐standing nanofiber membranes with sustained bacterial fouling resistance, with potential in applications in filtration and water treatment technologies for which antifouling strategies are imperative. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47580.

High filtration efficiency fluffy material: nano-fiber constructing gradient structure on recycled curved PET micro-fibers web

High efficiency filtration materials focus on electreted melt-blown polypropylene nonwoven and nano-scale fibers membrane in industry. However, the charge decay and the balance of efficiency and resistance are still facing challenges on research and practical applications. In this research, combined with traditional electrospinning and carding process, a simple and new fluffy gradient filtration material was designed by constructing nano-scale poly(lactic acid) (nano-PLA) fiber membranes on recycled three-dimensional curved poly(ethylene terephthalate) (R-PET) micro-fibers webs. Influences of basis weights of nano-PLA membranes and curved types of R-PET fibers on the filtration performance and the dust-holding capacity of R-PET/nano-PLA mats were investigated. Besides, the filtration mechanism of R-PET/nano-PLA mats was systemically studied. Results show that R-PET with zigzag curve (R/Z-PET) possesses the highest filtration efficiency of 99.992% comparing with 99.517% of linear R-PET, the pressure drop fall to 201.11 Pa, and a quality factor level up from 0.024 to 0.047 Pa−1. The pressure raising rate of the R/Z-PET/nano-PLA mat is the slowest. R/Z-PET fibers with a folding angle of 90° benefit to decrease the friction between fiber and particles when the location angle of zigzag fiber is 45° along the airflow direction, which decrease the pressure drop at high filtration efficiency. Surface residual charges contribute some effect on the overall filtration performance of the R-PET/nano-PLA mat. A new way of simple curved micro-PET fiber combining with nano-scale fibers provides an industrial available path to mass production of high efficiency filtration material serving for air pollution control without electret process.

Thermal properties and structure of electrospun blends of PVDF with a fluorinated copolymer

ABSTRACTWe report the structure and thermal properties of blends comprising poly(vinylidene fluoride) (PVDF) and a random fluorinated copolymer (FCP) of poly(methyl methacrylate)‐random‐1H,1H,2H,2H‐perfluorodecyl methacrylate, promising membrane materials for oil–water separation. The roles of processing method and copolymer content on structure and properties were studied for fibrous membranes and films with varying compositions. Bead‐free, nonwoven fibrous membranes were obtained by electrospinning. Fiber diameters ranged from 0.4 to 1.9 μm, and thinner fibers were obtained for PVDF content >80%. As copolymer content increased, degree of crystallinity and onset of degradation for each blend decreased. Processing conditions have a greater impact on the crystallographic phase of PVDF than copolymer content. Fibers have polar beta phase; solution‐cast films contain gamma and beta phase; and melt crystallized films form alpha phase. Kwei's model was used to model the glass transition temperatures of the blends. Addition of FCP increases hydrophobicity of the electrospun membranes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 312–322

A Facile Approach for Preparing Ag Functionalized Nonwoven Polypropylene Membrane to Improve Its Electrical Conductivity and Electromagnetic Shielding Performance.

The commonly used preparation methods of polypropylene functionalization require special equipment to be put into use or take a long time, which limits its application. Therefore, a simple and economical method for preparing silver functionalized nonwoven polypropylene membrane was studied herein. Triethanolamine was first coated on the surface of the polypropylene, and then Ag was deposited on the surface of polypropylene using a continuous reduction reaction of triethanolamine and silver ions. Surface morphology, crystal structure, and surface chemistry during the preparation of Ag functionalized nonwoven polypropylene were investigated. The electrical conductivity, electromagnetic shielding properties, and washing durability of the treated nonwoven polypropylene were also studied. It was found that Ag was uniformly deposited on the surface of the nonwoven polypropylene, and the coating reaction did not change the chemical structure of the polypropylene. The crystallinity and thermal stability of polypropylene were improved after silver coated polypropylene. The washing experiment results showed that the weight gain rate of the treated nonwoven relative to the untreated sample after the 90 min washing ranged from 6.72% to 9.64%. The resistance test results showed that the maximum surface resistivity of Ag coated nonwoven polypropylene was about 1.95 × 105 Ω, which was 64,615 times lower than the original. In addition, the results showed that the maximum electromagnetic shielding effectiveness of the Ag coated nonwoven polypropylene was about 71.6 dB, showing a very good electromagnetic shielding effect.

Unexpectedly high piezoelectricity of electrospun polyacrylonitrile nanofiber membranes

Polyvinylidene fluoride (PVDF) and its co-polymers are among the best piezoelectric polymer materials owing to the large piezoelectric coefficient and mechanical properties. Processing PVDF polymers into fibrous membranes through electrospinning can largely increase the piezoelectricity. In contrast, polyacrylonitrile (PAN), an amorphous polymer, is known to have a much lower piezoelectricity than PVDF. Herein, we report an unusually-high piezoelectric feature of electrospun PAN nanofiber membranes. When a small piece of PAN nanofiber nonwoven membrane (e.g. 5 cm2) was subjected to compressive impact, it can generate up to 2.0 V of voltage, the electrical outputs of which are even higher than that of PVDF nanofiber membranes at the same condition. Such unexpected piezoelectric properties were found to originate from the high content of planar Sawtooth PAN conformation within nanofibers. Electric charges in PAN nanofibers also contributed to the energy conversion. The energy conversion capability can be further enhanced by increasing fiber orientation within fibrous membrane. Also, the working area and thickness of nanofibrous membranes as well as impact conditions influenced piezoelectric outputs. The energy generated is usable and can power commercial LEDs. These unexpected discovery may inspire to develop novel piezoelectric materials and devices.

Feasibility study on a double chamber microbial fuel cell for nutrient recovery from municipal wastewater

Microbial fuel cell (MFC) is currently considered a promising technology for wastewater treatment. This study aims to evaluate the feasibility of a double-chamber MFC in terms of: (i) operating mode (batch mode, self-circulation mode, single-continuous mode) of anolyte on the nutrient accumulation in the catholyte, (ii) aeration conditions (anode effluent with aeration supplied in catholyte; anode effluent without aeration supplied in catholyte; cathode effluent with aeration supplied in catholyte and cathode effluent without aeration supplied in catholyte) on the nutrient recovery and (iii) types of separators (cation exchange membrane (CEM), forward osmosis (FO), and nonwoven (NW)) to remove nutrients toward their recovery from municipal wastewater. Results showed that there was no negligible increase in the phosphate concentration of the catholyte at the three different modes but accumulation of ammonium. At different aeration conditions, nutrients can be recovered by chemical precipitation at high pH generated by the MFC itself. Basically, phosphate was removed by microbial absorption and recovered by chemical precipitation while ammonium was accumulated by current generation and recovered as precipitates. It was found that double-chamber MFC with the CEM as the separator reported the best nutrients removal with >97.58% of NH4+-N and >94.9% of PO43−-P removed/recovered, followed by the MFC with the nonwoven and FO membrane, respectively. Thus, the double-chamber MFC is feasible for recovering nutrients in a comprehensive bioelectrochemical system.

The Influence of Geotextile Type and Position in a Porous Asphalt Pavement System on Pb (II) Removal from Stormwater

Porous asphalt (PA) pavement systems with and without a geotextile layer were investigated in laboratory experiments to determine the impacts of the geotextile layer on the processes leading to lead ion (Pb2+) removal from stormwater runoff. Two types of geotextile membranes that were placed separately at upper and lower levels within the PA systems were tested in an artificial rainfall experiment while using synthetic rainwater. The effect of storage capacity within the system on Pb2+ removal was also investigated. Results indicated that the use of a geotextile layer resulted in a longer delay to the onset of effluent. The non-woven geotextile membrane that was placed below the reservoir course improved the Pb2+ removal rate by 20% over the removal efficiency of the system while using a woven geotextile placed just below the surface but before the choker course. Pb2+ ions were reduced by over 98% in the effluent after being held for 24 h in reservoir storage. Results suggest that temporary storage of stormwater in the reservoir course of a PA system is essential to improving Pb2+ ion removal capability.

Electrospun nanofiber cloud for ultrafast solid phase micro-extraction of trace organics in water samples

In order to achieve ultrafast solid phase micro-extraction (SPME) of trace organics in water samples, the robust polyimide/polyvinylpyrrolidone (PI/PVP) composite nanofiber was prepared by electrospinning. Unlike the nonwoven electrospun membrane bulk widely used for SPME, the hydrophilic PI/PVP nanofibers here can be easily dispersed into and recovered from water sample like a cloud, so nanofiber cloud SPME (NC-SPME) was proposed in this work. The extraction performance of the NC-SPME method was evaluated using phthalates and organochlorine pesticides as model analytes. The extracted analytes were then desorbed by acetone and eventually quantified by gas chromatography-mass spectrometry (GC–MS). The extraction equilibrium was reached in 30 s for most of the phthalates and 2 min for organochlorine pesticides. While for bar-SPME, the equilibrium time was much longer than 2 h. At the extraction time of 5 min, the recoveries of phthalates and organochlorine pesticides were more than 34% and 52% by the NC-SPME method while they were less than 15% and 10% respectively by the bar-SPME method. In a word, the NC-SPME method presented significant advantages such as fast equilibrium and high recoveries compared to bar-SPME. For the phthalates analysis of real samples by NC-SPME, 5 mL of water sample was used for a 5-min extraction, linear range covered 1–2 orders of magnitude with correlation coefficients (r) higher than 0.99 and limits of detection (LODs) at ng/L levels for all of the tested water samples. This method will be useful for the rapid micro-extraction of other kinds of organics in water samples even biological fluid samples due to the stable composition, ultra-hydrophilic surface of PI/PVP nanofiber, and the biocompatible nature of PVP.

Promising Free-Standing Polyimide Membrane via Solution Blow Spinning for High Performance Lithium-Ion Batteries

Solution blow spinning (SBS) is a novel scalable process to fabricate nanofibrous mat with high efficiency and security. Herein, as a proof of concept, we adopt SBS methodology to prepare a kind of free-standing polyimide nonwoven membrane with adhesion morphology among an interconnected network and employ it as a potential lithium-ion battery separator successfully. Results manifest that as-prepared polyimide membrane possesses satisfactory porosity (87.3%), excellent thermal stability (no shrinkage even up to 180 °C), and admirable electrolyte wettability, which further significantly improves the ionic conductivity (1.74 mS cm–1). In addition, cells assembled with polyimide membranes deliver outstanding cycling performance and C-rate discharge capability compared with Celgard 2400 in the same conditions. Overall, this study reveals that SBS as a facile spinning-strategy might be easily converted into continuous production on an industrial scale and, along with the aforementioned charming features, indic...