Composite Nanofiber Membranes Research Articles

Poly(vinyl alcohol)/Melamine Composite Containing LATP Nanocrystals as a High-Performing Nanofibrous Membrane Separator for High-Power, High-Voltage Lithium-Ion Batteries

Electrolyte uptake and thermal stability of separators are important factors in Li-ion battery application. Here, a poly(vinyl alcohol)/melamine composite nanofiber membrane containing LATP nanocry...

Scalable Manufacturing of MXene Films: Moving toward Industrialization

Industry-scale manufacturing techniques hold the key to the ultimate commercialization of MXene products. In Matter, Taylor, Gogotsi, and colleagues demonstrate a drop-casting method to prepare scalable and micro-patternable MXene films on hydrophobic substrates, highlighting the excellent potential for the commercial application in electromagnetic interference shielding.

Composite Polymer Electrolyte Membranes based on Nafion and Modified PVDF Electrospun Nanofiber Mats

We fabricated the nanofiber composite membranes by impregnating Nafion into the modified polyvinylidene fluoride(PVDF) electrospinning nanofiber mat for proton exchange membrane fuel cells applications. The hydrophobic PVDF nanofibers mat became to the hydrophilic state by alkali treatment for the full embedding of Nafion into the PVDF network. The fabricated composite membranes exhibit significantly enhanced thermal stabilities, swelling resistance, and observably improved mechanical property compared to the pristine Nafion membrane. When the content of PVDF nanofiber mat is 15.1wt% in the membrane, the proton conductivity of the nanofiber composite membrane is nearly equal to that of pristine Nafion membrane with the same condition. The experimental results show that the prepared composite membrane can be used as a promising polyelectrolyte membrane for fuel cell applications.

Superhydrophobic and anti-ultraviolet polymer nanofiber composite with excellent stretchability and durability for efficient oil/water separation

Superhydrophobic nanofibrous membranes have attracted tremendous attention to deal with some environmental problems like oil leakage and wastewater treatment; however, their poor durability, recyclability and stability limit their broad applications in the complex and harsh water treatment. Here, we prepared a superhydrophobic, anti-ultraviolet, durable and stretchable nanofiber composite membrane. TiO2 nanoparticles were anchored onto the thermal plastic polyurethane (PU) nanofiber surface by ultrasonication, followed by polydimethylsiloxane (PDMS) modification. PDMS could decrease the nanoparticle surface energy and hence improve the hydrophobicity of the nanofibrous membrane. More importantly, it was served as a “glue”, significantly enhancing the interfacial adhesion between the TiO2 nanoparticles and PU nanofibers and thus the mechanical properties. The obtained composite membrane displayed excellent corrosion resistance and UV blocking performance, which could be maintained after cyclic mechanical tests. The superhydrophobic/superoleophilic nanofiber composite could separate oil with not only water but also salt, acid and alkaline solution. In addition, the nanofiber membrane could be repeatedly used with the stable separation flux and efficiency, displaying great durability and recyclability.

High-flux anti-fouling nanofibrous composite ultrafiltration membranes containing negatively charged water channels

High-flux nanofibrous composite ultrafiltration (UF) membranes consist of nanocellulose integrated polyacrylonitrile (PAN) as the barrier layer and electrospun PAN nanofibers deposited on a polyethylene terephthalate (PET) non-woven mat as the supporting layer were fabricated by solution coating approach. The chemical composition of nanofibrous composite membranes was investigated with ATR-FTIR, TGA, and EDX measurements, while the top and cross-sectional morphology of the membranes were observed via SEM and AFM scans. An interpenetrating nanofiber-polymer network was created in the barrier layer which drastically enhanced the mechanical strength of the composite membrane. The hydrophilicity of the nanofibrous composite membranes increased with nanocellulose component evidenced by water contact angle measurements, which could enhance the anti-fouling properties of the membranes. The as-prepared membranes were investigated for protein separation and wastewater treatment. The ultrafiltration performance of nanofibrous composite membranes with different composition ratios of nanocellulose to PAN was demonstrated using a cross-flow filtration system, the highest pure water permeability of 1508 L/(m2h·MPa) was achieved with a coating solution of 0.10 wt% of nanocellulose and 0.05 wt% of PAN where it created optimized water channels in the barrier layer of the composite membranes. The molecular weight cut-off (MWCO) of these membranes was determined with dextran as a marker, where the maximum pore size of the membranes varied in the range of 20.8–46.0 nm. Moreover, proteins and polypeptides with different molecular weights were employed to challenge the nanofiber composite membrane performance. High permeation flux of 147.1 L/m2h and high rejection ratio of 98.4% were accomplished; meanwhile, the high selectivity against protein and polypeptides was attained, indicating the membrane's applicability for the selective separation. The anti-fouling properties of the nanofibrous composite membranes were also intensely investigated and the filtration efficiency, in terms of permeation flux and rejection ratio, was evaluated and compared with that of commercially available UF membranes (UN100, US050, and UE050) that possess similar membrane pore size. The permeation flux of the nanofibrous composite membrane was 2–3 times higher than that of commercial membranes, due to the formation of water channels in the barrier layer, while the rejection ratio remained the same as 99.6%, indicating that the nanofibrous composite membrane could be a good candidate for wastewater treatment, in addition to the highly selective separation of proteins.

GO/Bi2S3 Doped PVDF/TPU Nanofiber Membrane with Enhanced Photothermal Performance.

Photothermal conversion materials have attracted wide attention due to their efficient utilization of light energy. In this study, a (GO)/Bi2S3-PVDF/TPU composite nanofiber membrane was systematically developed, comprising GO/Bi2S3 nanoparticles (NPs) as a photothermal conversion component and PVDF/TPU composite nanofibers as the substrate. The GO/Bi2S3 NPs were synthesized in a one-step way and the PVDF/TPU nanofibers were obtained from a uniformly mixed co-solution by electrospinning. GO nanoparticles with excellent solar harvesting endow the GO/Bi2S3-PVDF/TPU membrane with favorable photothermal conversion. In addition, the introduction of Bi2S3 NPs further enhances the broadband absorption and photothermal conversion properties of the GO/Bi2S3-PVDF/TPU composite membrane due to its perfect broadband absorption performance and coordination with GO. Finally, the results show that the GO/Bi2S3-PVDF/TPU composite membrane has the highest light absorption rate (about 95%) in the wavelength range of 400–2500 nm. In the 300 s irradiation process, the temperature changes in the GO/Bi2S3-PVDF/TPU composite membrane were the most significant and rapid, and the equilibrium temperature of the same irradiation time was 81 °C. Due to the presence of TPU, the mechanical strength of the composite film was enhanced, which is beneficial for its operational performance. Besides this, the morphology, composition, and thermal property of the membranes were evaluated by corresponding test methods.

Solution blow spinning–polyacrylonitrile–assisted cellulose acetate nanofiber membrane

Cellulose-based nanofiber membrane fabrication remains a global challenge, especially the use of alternative and sustainable sources of cellulosic materials. Herein, an easy and highly scalable cellulose-based nanofiber membrane was successfully fabricated using a solution blow spinning (SBS) method. Such membrane fabrication was carried out with the assistance of an easy-to-spin precursor polymer (i.e. polyacrylonitrile (PAN)). Through this strategy, cellulose acetate (CA) was successfully spun into a ready-to-use membrane. The formation of CA with the PAN nanofiber is concentration-dependent and requires high air pressure to effectively overcome the composite precursor’s surface tension and eventually produce nanofibers. Favourable CA concentration in PAN (i.e. 50%–65% v/v CAN/PAN) is important to the formation of sufficient molecular entanglement with PAN in solution. Upon fulfilling the optimized CA concentration, high air pressure (i.e. ≥3 bars) is used to produce jet-like polymeric fibers of PAN dragging off CA, forming numerous nanofibers which are then collected into a substrate forming a membrane. Characterizations of the CA/PAN composite nanofiber were carried out using scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis and differential scanning calorimetry (DSC). Such unique composite nanofiber membranes have potential as filters and adsorbent membranes for air and water/wastewater applications, as well as for biorefinery applications.

A Sm-doped Egeria-densa-like ZnO nanowires@PVDF nanofiber membrane for high-efficiency water clean

A biomimetic Egeria-densa-like hybrid composite nanofiber membrane was fabricated to degrade organic pollutants in water, with PVDF nanofibers as stems to provide support, and ZnO nanowires as leaves to provide active sites. The Sm-doped ZnO nanowires@PVDF nanofiber membranes were characterized by FE-SEM, X-ray photoelectron spectroscopy, Fourier transform infrared, X-ray diffraction, and UV–vis diffuse reflectance spectrometer. Compared with the pure ZnO nanowires@PVDF nanofiber membrane, the Sm-doped membrane showed higher photocatalytic performance. The excellent photocatalytic activity was attributed to the increased specific surface area and the decreased bandgap of ZnO nanowires after Sm doping, which inhibited the recombination rate of electrons and holes and improved the absorption of visible light. We found that the superoxide free radicals (O2−) played a critical role in photocatalytic degradation. The Sm-doped ZnO nanowires@PVDF nanofiber membrane exhibited good stability after 5 cycles of RhB degradation. We believe such Sm-doped hybrid membrane can work as an effective photocatalyst for wastewater treatment.

RETRACTED: Cross-linked β-cyclodextrin nanofiber composite membrane for steroid hormone micropollutant removal from water

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/about/our-business/policies/article-withdrawal ). This article has been retracted at the request of the authors. This publication contains SEM images in the supporting information that appear to have been manipulated. After careful examination of the first author’s SEM records, lab books and experimental data, the SEM image manipulation was verified. The lab book showed incomplete entries and data recording while analysis of primary data and overall conclusions appear generally sound. The authors are retracting the paper and apologize for the inconvenience.

Nanofiber composite membrane using quantum dot hybridized SPEEK nanofiber for efficient through-plane proton conduction

Nanofiber composite membrane (NFCM) shows great potential for utilization as proton exchange membrane due to the ultrahigh in-plane proton conduction ability, but impeded by the inferior through-plane conductivity, i.e., serious conduction anisotropy. Herein, hybrid sulfonated poly(ether ether ketone) (SPEEK) nanofiber was fabricated for the first time by uniformly filling 2–5 nm quantum dots (QDs). Then, chitosan was incorporated into the pores of fiber mat for the preparation of hybrid nanofiber composite membrane (HNFCM). The filled QDs can provide a large number of proton-conducting groups (–NH–/–NH2 and –CO2H). Especially, the –NH–/–NH2 groups form ordered acid-base pairs with the –SO3H groups in SPEEK, providing low-barrier pathways for proton hopping through the nanofiber. In this way, the HNFCM displays significantly enhanced both through-plane and in-plane proton conduction, decreased transfer anisotropy, and thereby boosted hydrogen fuel cell performance. Particularly, the through-plane conductivity as high as 456 mS cm−1 is achieved by this HNFCM at 90 °C and 100% RH, which is almost 3 times of that of relevant NFCM without QDs. This then brings one time increase in cell power density. And the influence of functional group loading in QDs on membrane performance is also explored.

Waterproof and breathable polyacrylonitrile/(polyurethane/fluorinated-silica) composite nanofiber membrane via side-by-side electrospinning

Abstract

Preparation of Waterproof and Breathable Polyurethane Fiber Membrane Modified by Fluorosilane-modified Silica

Polyurethane is a thermoplastic elastomer with excellent physical and chemical properties, the hydrophilicity of PU limits the wide application in the waterproof and breathable materials market. In this study, SiO2 nanoparticles were hydrophobically modified by fluorosilane to prepare the fluorosilane-modified silica (F-SiO2), then it was added into the synthesized polyurethane to prepare waterproof and breathable film (F-SiO2/PU) by electrospinning. Compared with polyurethane membranes, F-SiO2/PU composite membranes could form rough morphological surface through the blending of F-SiO2. The experimental results showed that the water contact angle of the composite nanofiber membranes increase with the addition of the amount of modified silica, and the water contact angle reached 135 o when the dosage of F-SiO2 was 5 wt%. The composite nanofiber membranes could be endowed with excellent waterproof performance, hydrophobicity (50 kPa) and moisture permeability (10.4 kg/m2•h). Besides, the prepared membrane can remain the hydrophobic property stability under the dynamic tensile of large-scale deformation.

Fabrication and Properties of a Biomimetic Dura Matter Substitute Based on Stereocomplex Poly(Lactic Acid) Nanofibers.

BackgroundDuraplasty is one of the most critical issues in neurosurgical procedures because the defect of dura matter will cause many complications. Electrospinning can mimic the 3D structure of the natural extracellular matrix whose structure is similar to that of dura matter. Poly(L-lactic acid) (PLLA) has been used to fabricate dura matter substitutes and showed compatibility to dural tissue. However, the mechanical properties of the PLLA substitute cannot match the mechanical properties of the human dura mater.Methods and ResultsWe prepared stereocomplex nanofiber membranes based on enantiomeric poly(lactic acid) and poly(D-lactic acid)-grafted tetracalcium phosphate via electrospinning. X-ray diffraction results showed the formation of stereocomplex crystallites (SC) in the composite nanofiber membranes. Scanning electron microscope observation images showed that composites nanofibers with higher SC formation can keep its original morphologies after heat treatment, suggesting the heat resistance of composite nanofiber membranes. Differential scanning calorimeter tests confirmed that the melting temperature of composite nanofiber membranes was approximately 222°C, higher than that of PLLA. Tensile testing indicated that the ultimate tensile strength and the elongation break of the stereocomplex nanofiber membranes were close to human dura matter. In vitro cytotoxicity studies proved that the stereocomplex nanofiber membranes were non-toxic. The neuron-like differentiation of marrow stem cells on the stereocomplex nanofiber membranes indicated its neuron compatibility.ConclusionThe stereocomplex nanofiber membranes have the potential to serve as a dura mater substitute.

Preparation of multifunctional AgNPs/PAN nanofiber membrane for air filtration by one-step process

PurposeThe purpose of this paper is to fabricate a high-performance filtration electrospun nanofiber membrane with antibacterial function. The Ag nanoparticles (AgNPs) gotten by reducing AgNO3 act as antimicrobial agent. Then the AgNPs/Polyacrylonitrile (AgNPs/PAN) composite nanofiber membrane was prepared by electrospinning.Design/methodology/approachThe electrospun Ag/PAN composite membrane was prepared by one step, in which the Ag particles were acting as antibacterial agent and PAN nanofiber as the upholder of the composite mat. AgNPs were obtained by reducing AgNO3 in N,N-Dimethylformamide (DMF) solution at high temperature. Meanwhile, the PAN particles were added to DMF solution and dissolved. Then the Ag/PAN nanofiber was obtained by electrospinning.FindingsThe thinner nanofiber can be produced with PAN concentration of 12 per cent and AgNPs concentration of 10 per cent. Finally, the filtration resistance of the composite membrane with antibacterial property is as high as 99.1 per cent, and the filtration efficiency is only 83 Pa. Therefore, the AgNPs/PAN composite membrane is the ideal choice for air filtration with antibacterial property.Originality/valueThe AgNPs/PAN composite nanofiber membrane has high filtration performance for particulate matter (PM)25 and outstanding antibacterial property to Escherichia coli and Staphylococcus aureus, which can be used with masks, air-conditioning filters (including car air-conditioning filters), window screening and other similar objects.

Preparation, characterization and photocatalytic performance of heterostructured CuO-ZnO-loaded composite nanofiber membranes.

Inorganic semiconductor oxides loaded on composite nanofibers (CNFs) have been widely applied in environmental monitoring, industry, aviation, and transportation. In this paper, heterostructured CuO–ZnO-loaded CNF membranes (CNFMs) were prepared successfully by a combination of electrospinning, heat treatment, and hydrothermal synthesis. The influence of the synthesis parameters on morphology, structure, and properties of the CNFMs was investigated, and the optimal process parameters were determined. Then, the CNFMs obtained with optimal process parameters were applied for the photocatalytic degradation of methyl orange. It was found that the CNFMs could be reused to degrade methyl orange at least three times, and the degradation rate remained above 90%.

Synergistic effect of one-dimensional silk nanofiber and two-dimensional graphene oxide composite membrane for enhanced water purification

Bombyx Mori silk-derived silk nanofiber (SNF; one dimensional, 1D) is assembled in the active functional group on the surface of graphene oxide (GO; two dimensional, 2D) composite membranes with an average thickness of 36–72 nm. The possibility of large-scale production through a simple chemical synthesis method with solutions of different pH levels of the SNF can be advantageous. The SNF/GOx composite membranes having a combination of 1D nanofiber and 2D materials possess a synthetic effect in the effective rejection rate of salt and dye. Investigation of the physicochemical properties of the SNF/GO composite membrane revealed that SNF interlaces the cavity I4 formed among the GO sheets to promote water flux. The hydrogen bonding interface between SNF and GO forms a specific water channel I3 to ensure the selectivity of Na2SO4 salt rejection. The 1D/2D synergy reveals a flux value of 43 LMH and a rejection value of 95% (up to 1000 ppm at 1.0 MPa pressure). The SNF/GO composite membrane exhibits good stability and increased operating pressure with increasing flux rate and constant rejection values. In addition, the SNF/GO5 wt% composite membrane exhibits excellent dye removal of up to 97%. The results demonstrate the potential of the SNF/GO5 wt% composite membrane to be used for water treatment in practical applications.

A Robust Carbon Nanotube and PVDF-HFP Nanofiber Composite Superwettability Membrane for High-Efficiency Emulsion Separation.

Oil or chemical purification is significant not only for industrial safety production but also because it conforms to the principle of sustainable development. In this paper, based on the synergistic concept of superwettability and nanopores sieve effect, a superoleophilic and under-oil superhydrophobic carbon nanotube/poly(vinylidene fluoride-co-hexafluoropropylene) nanofiber composite membrane is prepared via electrospinning, pressure-driven filtration, and chemical vapor modification. The as-prepared membrane with durable mechanical and chemical stabilities achieves separation efficiency higher than 99.9% and high flux up to 632.5 L m-2 h-1 bar-1 for different water-in-oil emulsions. This membrane is highly promising for the petroleum and chemical industries for both product quality improvement and green recycling manufacturing processes.

Preparation and biological properties of collagen/nano-hydroxyapatite composite nanofibers based on ordered nano-hydroxyapatite ceramic fibers

Man-made materials are easily available, processed and modified during bone defect repairing, without worrying about potential infections, immunological incompatibility, sterility, or donor site morbidity. Collagen(Col)/nano-hydroxyapatite (nHA) composite nanofibers based on ordered nHA ceramic fibers was prepared by sintering electrostatic spinning PVP/HA composite fibers followed by impregnation with collagen solution. Without requiring strict control of temperature or humidity, this method prevented nHA aggregation during the sintering process and reduced the use of costly Col as compared with direct electrospinning. The composite nanofiber membrane with bone-like components and structures has a great potential for application in bone tissue engineering. And the method implement easily.. The mineralization and degradation characteristics of the nanofiber biocomposite are beneficial for the bone conductivity and MSCs growth and metabolism. Protein adsorption of Col/HA nanofiber biocomposite is outstanding. There is no significant difference in cells viability between the experiment group and the control group, and Col/HA nanofibers biocomposite has weak cytotoxicity to MSCs. Overall, the approach successfully prepared Col/HA nanofibers biocomposite at common electrospinning environment with uniformly distributed high content nHA, low Col concentration and less Col consumption, all of which make it an excellent choice for the bone tissue engineering.

Preparation and Properties of PVDF/Fe3O4 Nanofibers with Magnetic and Electret Effects and their Application in Air Filtration

AbstractElectrospun electret filter material is widely studied because of its excellent removal effect on particulate matter from air streams. Here, a kind of high efficiency and low pressure drop nanofiber (NF) membrane with both electret effect and magnetic effect is developed, and compounded it with glass fiber mesh and polyester (polyethylene terephthalate) mesh to prepare a sandwich structure of NF anti‐haze window screen. Under the synergistic effect of magnetic particles, when the density is 2.06 g m−2, the filtration efficiency of NF anti‐haze window screen can reach 99.95% for the fine particles below 0.3 µm, while the filtration pressure drop is only 58.5 Pa, with good light transmittance and excellent breaking strength (6.32 MPa). Therefore, polyvinylidene fluoride/Fe3O4 composite NF membrane has a potential application prospect in the field of air filtration.

Stereocomplex poly(lactic acid)-based composite nanofiber membranes with highly dispersed hydroxyapatite for potential bone tissue engineering

The development of materials with excellent mechanical properties and stem cell affinity for bone repair is a topic that has received significant interest in the field of bone tissue engineering. In this study, stereocomplex poly(lactic acid)-based composite nanofiber membranes that are compatible with bone marrow stem cells (BMSCs) were prepared with poly(d-lactic acid)-grafted hydroxyapatite and enantiomeric poly(lactic acid)s. The mechanical property tests showed that, compared with those from a heated poly(l-lactic acid) (PLLA) nanofiber membrane, the tensile strength and Young's modulus of the most strengthened composite nanofiber membrane herein increased by 30.16% and 34.56%, respectively. The X-ray diffraction results indicated that the stereocomplex crystallite (SC) of poly(lactic acid) formed in heated composite nanofiber membranes. The differential scanning calorimetry results showed that the melting temperature of the SC of heated composite nanofiber membranes was approximately 221 °C. Live/dead staining and scanning electron microscopy were used to observe the proliferation and adhesion of BMSCs cultured on the nanofiber membranes. Compared with the PLLA nanofiber membrane, increased type I collagen expression and improved formation of bone-like nodules can be observed after induction for nine days on the composite nanofiber membrane, indicating the potential application of the composite nanofiber membrane for bone tissue engineering.