One-step Electrospinning Method Research Articles

Cellulose acetate-based composite fibrous mat with mechanically stable pore structure showing excellent hydrophobicity for effective oil spill treatment

Eco-friendly cellulose acetate (CA) based composite fibrous mat with mechanically stable pore structure and rough fibers is successfully fabricated via a simple and one-step electrospinning method. Based on the phase migration during electrospinning, the flexible polymer of thermoplastic polyurethane (TPU) with low surface tension tends to concentrate on the surface of the CA/TPU composite fibers, endowing the fibrous mat exhibiting hydrophobicity and super-oleophilicity. The TPU component creates the bonding among composite fibers, stabilizing the pore structure by increasing the modulus and tensile strength of the CA/TPU fibrous mat. Finally, the as-designed CA/TPU composite fibrous mat could selectively and efficiently absorb various oils from oil-water mixtures featuring high saturation absorption capacity of 28.35–64.18 gg-1 and excellent durability. Besides, the CA/TPU composite fibrous mat exhibits exceptional environmental stability and a continuous oil-water separation capacity to purify the polluted water, revealing a great potential for practical application.

Ion-induced electrospinning of hierarchical spiderweb-like bioscaffolds

Tissue engineered scaffolds need to possess various functionalities, including biocompatibility, mechanical support, bioactivity, and vascularization. The design and fabrication of bioscaffolds to attain mutual coordination among these functionalities with minimal processing complexity are a highly challenging but rewarding task. In this study, a simple, effective one-step electrospinning method was developed to fabricate hierarchical spiderweb-like bioscaffolds that achieve both superior biological and mechanical functionalities. By incorporating ionic drugs of deferoxamine mesylate and lithium chloride, the spiderweb-inspired structures with adjustable coverages (up to 100 %) were successfully created, imparting the fibrous bioscaffolds with remarkable tensile strengths (∼88.28 MPa). The strengthening mechanisms endowed by the spiderweb structure in optimizing stress distribution to delay damage and enhance load-bearing ability were elucidated through finite element simulations. Furthermore, this hierarchical spiderweb-like bioscaffold demonstrated favorable biological characteristics, including biocompatibility, osteogenesis, angiogenesis, and hemostasis. The presence of the nano-spiderweb structures significantly improved cell adhesion and differentiation on the scaffold and increased the spreading area of cells by 2–3 times. The dual-drug loaded bioscaffolds with full coverages of the spiderweb structure exhibited the least amount of bleeding (45.33 ± 27.47 mg) and the fastest hemostasis speed (82 ± 8.19 s) in the hemostasis test, compared to the control group. Overall, the outstanding performance makes the developed bioscaffolds a promising alternative for tissue repair and regeneration in the field of tissue engineering.

Promoted adsorption-photocatalysis synergistic removal of contaminants via surface regulation by a tree-like nanofiber membrane substrate

Photocatalysis represents a promising strategy for wastewater treatment, but the widely used powder photocatalysts are still limited by sluggish interfacial mass transfer and chemical processes. In this study, a tree-like PVDF nanofiber membrane (T-PVDF) was explored to enhance the photocatalytic activity of TiO2 and TiO2/BiOI heterojunction through different pathways. TiO2 was first integrated into the T-PVDF substrate via a one-step electrospinning method. The dendritic architecture greatly favored the contaminant adsorption on the catalytic surface and thus boosted the photodegradation of RhB under UV or visible light irradiation. Especially for the visible light driven dye-sensitive photocatalysis, the integrated TiO2@T-PVDF outperformed the powder TiO2 and pristine PVDF membrane anchored TiO2 by 17.9 and 2.4 times, respectively. In addition, the construction of TiO2/BiOI heterojunction on the T-PVDF substrate was realized by further growing BiOI nanosheets via a solvothermal method. The irregular growth of BiOI on the multiscale nanofiber substrate formed a rough surface with unexpected high hydrophobicity, which allowed the accumulation of high-concentrated O2 at the catalytic interfaces. This greatly boosted the O2 reduction and inhibited the competitive H2 evolution under visible light irradiation, resulting in 3.8-fold higher reaction kinetics than that obtained for hydrophilic powder TiO2/BiOI heterojunction.

Controlled synthesis of Au@TiO2 mesoporous hollow nanofibers by one-step polyethylenimine-regulated electrospinning method for efficiently photocatalytic oxidation of CO

TiO2 mesoporous hollow nanofibers with excellent mass diffusion is an attractive photocatalytic material to remove toxic gaseous pollutants like CO, while it is highly desired to improve the photogenerated charge separation and O2 activation. Herein, the Au nanoparticles inner-loaded TiO2 mesoporous hollow nanofibers (Au@TO MPHNFs) have been controllably fabricated by one-step coaxial electrospinning, in which it is crucial to use polyethyleneimine as porogen and stabilizer for mesoporous and TiO2 in nanofibers shell. Concurrently, a stepwise phase transfer technique is employed to realize the uniform and stable dispersion of the Au in the paraffin oil as core precursor. The Au@TO MPHNFs exhibits 2.7 and 7.4-fold CO photooxidation enhancement compared with commercial P25 and TO MPHNFs, respectively. The enhanced photoactivity can be attributed to the creation of the mesoporous hollow structure for facilitating better mass transportation, and the incorporation of Au nanoparticles for efficient charge separation and O2 activation. Meanwhile, the photothermal effect of Au expedites intermediaries transformation and product desorption.

Polyoxometalates electron acceptor-intercalated In2O3@SnO2 nanofibers for chemiresistive ethanol gas sensors

Polyoxometalates (POMs), as a kind of electron acceptors, comes into sight in gas sensing field. Here, we in situ construct a group of polyoxomethoate/semiconductor one-dimensional tandem heterojunction materials using convenient one-step coaxial electrospinning method. A polyoxometalates electron acceptor layer was intercalated into In2O3@SnO2 nanofibers (NFs), forming In2O3@PW12@SnO2 coaxial core-middle-shell NFs. Gas sensing performances of the one-dimensional In2O3@PW12@SnO2 tandem heterojunctions were investigated for the first time. The fabricated NFs exhibited excellent detection performances for ethanol gas. The optimal sensitivity response to 100 ppm ethanol can reach 22.6, which is about 4 times that of POMs-free samples. Other gas sensing parameters were also comprehensively studied. The significant enhancement can be attributed to the addition of appropriate amount of PW12 electron acceptor which accelerate electrons transfer and reduce the recombination of electron-hole pairs. This work provides a novel strategy for developing high performance gas sensors by constructing tandem heterojunctions as well as introducing POMs electron acceptor, and offers new insight into the development of POMs-based gas sensors.

Dual phase change separator combining cooling and thermal shutdown functions for Li-ion battery with enhanced safety

The rapid growth of electric vehicles raises an unmet need to enhance high-temperature performance and safety of Li-ion battery (LIB). Herein, polyethylene glycol/polyvinylidene fluoride (PEG/PVDF) core @ polybutylene succinate (PBS) shell separator with cooling and thermal shutdown functions was fabricated using a one-step coaxial electrospinning method. The separator exhibited superior electrochemical performance even at room temperature due to good wettability and high porosity. When battery temperature rises as discharging, PEG with 50 °C melting point (m.p.) will melt to store heat temporarily. Thus, the separator with cooling function can effectively enhance ion conductivity to alleviate specific capacity drop and polarization voltage increase. As temperature decreases after battery discharging, the separator will release thermal energy to prepare for the next working cycle. When thermal runaway happens and raises temperate above 100 °C rapidly, the PBS shell will melt at 110 °C without skeleton thermal shrinkage. Separator pores can be blocked by the melted PBS and Li+ ions transfer can be inhibited in time to prevent disastrous consequence. Thus, dual phase change of the separator provides a novel and effective strategy for synergistic performance and safety enhancement of high temperature LIB.

Bifunctional MOF‐5@coal‐based fiber membrane for oil-water separation and dye adsorption

Water pollution caused by oily and textile wastewater has become a global concerned problem. Wastewater typically contains organic dyes, oil-water emulsions and other pollutants. Hence, it is crucially important to prepare materials that can separate oil-water mixtures/emulsions and adsorb organic dyes. In this work, the semi-encapsulated MOF-5 modified coal-based fiber membranes were prepared by one-step electrospinning method. The modified membrane exhibits superhydrophilic/underwater superoleophobic, excellent stability, high flux (oil-water mixture flux = 8861 L m-2 h-1, oil-in-water emulsion flux = 504 L m-2 h-1) and commendable separation efficiency (98.7%, 99.9%). The membrane could achieve a highly efficient dye absorption (94.9%). The semi-encapsulated construction makes the MOF-5 well protected and the active site can be greatly exposed, leading to significantly improved stability and adsorptive properties. The MOF-5 modification renders the surfaces hydrophilic and increases the roughness which improves water flux and wettability. The composite material provides a new idea for the separation of oil-water mixtures/emulsions and the adsorption of organic dyes.

Biocompatible, robust, waterproof and breathable PDMS-based PU fibrous membranes for potential application in wound dressing

Wound dressings, an effective tool for repairing injured skin and protecting it from secondary damage, have been widely manufactured. However, the design of wound dressings with waterproofness, breathability, mechanical robustness, and excellent biocompatibility remains a challenge due to the imbalance between the multiple desirable properties. Herein, a strategy is proposed to fabricate biocompatible membranes via a facile one-step electrospinning method. Polydimethylsiloxane-based polyurethane is effectively prepared to form durable hydrophobic surfaces, resulting in a high degree of hydrophobicity (141.0° water contact angle). The porous structure is enhanced by adjusting the solution concentration and heat treatment temperature, resulting in an optimal water vapor transmission rate of 8.2 kg·m−2·h−1. Additionally, the membrane exhibits a hydrostatic pressure of 52.3 kPa, which is approximately 14.1 times greater than that of PU fibrous membrane, and an enhanced tensile strength of 6.60 MPa. Moreover, the membrane can be utilized in a wide temperature range from − 123 °C to 160 °C due to its low glass transition temperature and exceptional thermal stability. Significantly, both in vitro and in vivo studies confirmed the remarkable biocompatibility and minimal toxicity to normal cells and mice skin. Our work presents a new approach to designing waterproof and breathable biomaterials with high mechanical strength, thereby enhancing their performance and functionality in the biomedical field, particularly in wound dressing applications.

Photocatalytic hydrogen production from seawater by TiO2/RuO2 hybrid nanofiber with enhanced light absorption

Compared to hydrogen production through pure water photocatalysis, the direct utilization of seawater for hydrogen production aligns better with the principles of sustainable development. Seawater, however, contains impurity ions like Na+ and Cl−, which pose higher demands on photocatalysts. It is widely acknowledged that RuO2 and TiO2 demonstrate excellent stability in seawater. Consequently, this study focuses on the model system of RuO2-modified TiO2 for investigating hydrogen production in simulated seawater. TiO2/RuO2 nanofibers (NFs) were synthesized via a one-step electrospinning method, ensuring intimate contact between the two components. The hydrogen production activity of TiO2/RuO2 NFs in simulated seawater nearly matches that in pure water. Remarkably, RuO2 serves as an oxidation cocatalyst, effectively scavenging holes from the valence band of TiO2 and enhancing the separation efficiency of electrons and holes. Interestingly, Cl− ions, similar to RuO2, contribute to reducing excess holes. This study lays the groundwork for future research into hydrogen production from seawater.

Evolution of In2O3 morphology from belt to fibrous-like structure for ethanol detection at low working temperature induced by Cr-addition

Herein, a high-performance ethanol functional nanosensor based on Cr-doped In2O3 nanofibers was produced via a one-step electrospinning method followed by annealing at 700 ℃. The combination of several systematic techniques showed that incorporation of Cr-dopant ions into In2O3 host lattice can effectively improve ethanol sensing capabilities of In2O3 nanofibers by reducing the operating temperature from 100 to 80 ℃, inducing additional oxygen vacancies, and increasing the content of chemisorbed oxygen ions at various Cr-doping levels. A comparison of the gas sensing performance findings of sensors based on the pure and Cr-doped In2O3 nanofibers at different doping levels of 0.5, 1, 1.5 mol% revealed that all Cr-doped sensors presented a high response and selectivity towards 50 ppm ethanol at 80 ℃ with a 1 mol% Cr-doped In2O3 sensor displaying the highest response of 12 which is 10 times higher than that of the pure In2O3 sensor. Furthermore, the response/recovery times of the 1 mol% Cr-doped In2O3 towards 50 ppm ethanol were 41/43 s while the minimum detection limit value was 2.19 ppm. With such rapid response kinetics, low detection limit, moisture resistant, Cr-doped sensors can be a promising active sensing layer for monitoring ethanol in real food environments.

Preparation and characterization of electrospun PVDF/PVP/SiO2 nanofiber membrane for oil-water separation

For oily wastewater purification, polyvinylidene fluoride (PVDF) nanofiber membranes have been widely noticed for their excellent mechanical strength and corrosion resistance. However, it is prone to serious oil fouling problems during use, resulting in reduced flux and inability to be used repeatedly. It has become a hot research topic to develop simple methods to realize its hydrophilic modification for oily wastewater treatment to address this problem. Herein, a novel separation membrane was prepared by doping polyvinylpyrrolidone (PVP) and hydrophilic silica nanoparticles (SiO2 NPs) into PVDF using a facile one-step electrospinning method. The modified membrane shows hydrophilicity, water contact angle (WCA) is 0°, oleophobicity in water, and oil contact angle (OCA) is more than 145° and has good separation efficiency and flux for both oil-water mixtures and emulsions. After 30 times of mixture and emulsion separation tests, the separation efficiency is above 99.5 % and 97 %, respectively, showing good separation and reusability. Besides, compared with hydrophilic modification methods such as surface coating and grafting, the proposed modification method is simpler and has great potential in treating oily wastewater.

Acid-resistant supramolecular nanofibrous hydrogel membrane with core-shell structure for highly efficient oil/water separation

Hydrogel is an ideal material for oily sewage treatment due to its strong hydration ability, low-adhesive and antifouling properties. Advanced hydrogel separation membranes with harsh-environment-tolerant (such as strong acidic environments) superoleophobicity are of significance but rarely reported. Herein, a supramolecular nanofibrous hydrogel membrane was designed via one-step coaxial electrospinning method with polyvinylidene fluoride (PVDF) as the reinforced core material. Dimethyl sulfoxide (DMSO) regulates hydrogen bond crosslinking between tannic acid (TA) and polyvinylpyrrolidone (PVP). With the evaporation of DMSO, the water-insoluble supramolecular shell was formed between PVP and TA, which was tightly wrapped around the PVDF core. The pore size and wettability of the resulting membrane could be tuned by the core/shell velocity ratio. The stable superwetting properties and interspatial connectivity endow the fibrous hydrogel membranes with high separation performance for various oil-in-water emulsions and even for strong acidic oil-water emulsion. The separation permeance can reach 22,293 L m−2 h−1 bar−1 for SDS stabilized acidic oil-water emulsion (pH = 1) and maintain at approximately 17,834 L m−2 h−1 bar−1 after 3 h continuous separation, exhibiting significant applicability for large-scale filtration.

Facile One-Step Electrospinning Process to Prepare AgNPs-Loaded PLA and PLA/PEO Mats with Antibacterial Activity.

Nanofibers can play an important role in developing new kinds of medical applications. Poly(lactic acid) (PLA) and PLA/poly(ethylene oxide) (PEO) antibacterial mats containing silver nanoparticles (AgNPs) were prepared by a simple one-step electrospinning method that allows AgNPs to be synthesized simultaneously with the preparation of the electrospinning solution. The electrospun nanofibers were characterized by scanning electron microscopy, transmission electron microscopy and thermogravimetry, while silver release over time was monitored by inductively coupled plasma/optical emission spectroscopy. The antibacterial activity was tested against Staphylococcus epidermidis and Escherichia coli by colony forming unit (CFU) count on agar after 15, 24 and 48 h of incubation. AgNPs were found to be mainly concentrated in the PLA nanofiber core, and the mats showed steady but slow Ag release in the short term; in contrast, AgNPs were uniformly distributed in the PLA/PEO nanofibers, which released up to 20% of their initial silver content in 12 h. A significant (p < 0.05) antimicrobial effect towards both tested bacteria, highlighted by a reduction in the CFU/mL counts, was observed for the nanofibers of PLA and PLA/PEO embedded with AgNPs, with a stronger effect exerted by the latter, confirming the more efficient silver release from these samples. The prepared electrospun mats may have good potential for use in the biomedical field, particularly in wound dressing applications, where a targeted delivery of the antimicrobial agent is highly desirable to avoid infections.

Preparation of bead-like PAN/ZIF-8 nanofiber membrane for methyl blue adsorption by one-step electrospinning

Bead-like PAN/ZIF-8 nanofiber membranes, of which the commercial ZIF-8 nanoparticles attached to the surface of PAN nanofibers, were prepared by a simple one-step electrospinning method. The fiber structures, electrospinning parameters and adsorption capacity to methyl blue were investigated. ZIF-8 distributed uniformly on the nanofiber, and the adsorption process followed the pseudo-second-order kinetics. Maximum adsorption capacity was obtained as 224.37 mg/g at ZIF-8 concentration of 10 wt%, methyl blue concentration of 100 mg/L, and time of 180 min. Our work provides a simple, cost-effective process for the fabrication of MOFs nanofiber membranes with good adsorption capacity that suitable for practical commercial applications.

One-step synthesis of n-CdO/n-SnO2 heterojunction nanofibers for high-performance 3-hydroxy-2-butanone gas sensing

Listeria monocytogenes (LM) is a pathogenic bacterium which can release 3-hydroxy-2-butanone (3H-2B) as a biological indicator. We report a high-performance 3H-2B gas sensing strategy for the selective detection of LM. This strategy is realized by n-CdO/n-SnO2 hetero-nanofibers with controllable compositions, synthesized via a facile one-step electrospinning method. The tailored morphologies and microstructures of CdO/SnO2 nanofibers were systematically characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). With the introduction of CdO into SnO2 nanofibers, x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the effects of crystal phases and elemental states on the 3H-2B sensing properties. According to the gas sensing results, the variation of Cd/Sn molar ratios has a great influence on the 3H-2B sensing properties of CdO/SnO2 nanofibers. The maximum response (45) to 5 ppm 3H-2B is found for 5 mol% CdO/SnO2 nanofibers at 260 °C. Meanwhile, 5 mol% CdO/SnO2 nanofibers exhibit a short response/recovery time (9 s/5 s), outstanding stability, and discriminative selectivity to 3H-2B. The enhanced sensing performance is mainly attributed to the synergy between the resistance modulation of n-CdO/n-SnO2 heterojunctions and the doping effect of Cd2+ ions.

Intrinsic microspheres structure of electrospun nanofibrous membrane with rational superhydrophobicity for desalination via membrane distillation

Electrospun nanofibrous membranes with superhydrophobicity are good candidates for membrane distillation (MD). In this study, we developed a facile one-step electrospinning method to prepare a superhydrophobic PVDF-HFP microsphere/nanofiber membrane in N-methyl-2-pyrrolidone (NMP). Then, the electrospun membrane was treated with ethanol-water solvent exchange. The fabricated membrane shows an interconnected microsphere-nanofiber structure with hierarchical micro-nano roughness. Due to the intrinsic microspheres on the nanofibers, the water contact angle of all microsphere/nanofiber membranes is higher than 150°. The optimal membrane exhibits superhydrophobicity, with a static contact angle of 156.6 ± 1.38° and a low sliding angle of 6.4 ± 0.2°. In a laboratory-scale direct contact membrane distillation (DCMD), the optimal membrane (with an effective membrane area of 9 cm2) shows a high permeate flux of 38.8 kg·m−2·h−1 and a salt rejection of 99.99% during a 40-h long-term desalination process. The superhydrophobic membrane exhibits excellent wetting and fouling resistance. Therefore, these properties will increase the water production of MD, thereby solving the problem of membrane wetting or fouling in wastewater treatment.

Surface oxygen vacancies modified ridge-like CeO2/ZnO nanobelts for enhancing photocatalytic activity

Ridge-like CeO2/ZnO nanobelts with tunable surface oxygen vacancies have been fabricated by a simple one-step electrospinning method. Different adding amounts of ZIF-8 (1, 3, and 5 wt%) are introduced into the electrospinning precursor solution for regulating the morphological evolution from porous nanobelts to 1D ridge-like or corrugated structure. The as-prepared ridge-like CeO2/ZnO nanobelts can display the superior photocatalytic activity for removing methylene blue (MB, 60 min, 95.12%), approximately 3.54 times than pure CeO2 nanobelts. The enhanced photocatalytic mechanism can be primarily ascribed from the unique ridge-like structure for generating a new transmission mode of electrons in CeO2/ZnO.

Efficient removal of phosphate from aqueous solution by mesoporous Zr/La hydroxide fibers prepared with high-pressure steam heat treatment

One-dimensional mesoporous Zr/La bimetallic hydroxide fibers (ZLFs) were prepared for the first time, by one-step electrospinning and high-pressure steam heat-treatment method, and they were used for effective removal of phosphate. The as-obtained fibers had a homogeneous composition and a large surface area, and they benefited from the high-pressure steam heat-treatment. Optimum heat-treatment conditions were confirmed, and the special hydrolysis mechanism in fibers and the Zr/La hydroxides formation process were analyzed. ZLFs with maximum surface area of 233.31 m2/g were obtained at a Zr/La mole ratio of 0.4:0.6. Influence of the Zr/La mole ratio of fibers on the adsorption property was examined; an impressive phosphate adsorption performance was observed with saturated adsorption capacity reaching 453.63 mg/g at a Zr/La mole ratio of 0.5:0.5. Notably, the ZLFs exhibited great anti-interference abilities against co-existing ions and pH values, along with good recycling performance. In summary, the ZLFs, produced via an easy method, with outstanding adsorption performance and high reusability, have great potential as adsorbents in the phosphate adsorption field.

Study on the Preparation and Lipophilic Properties of Polyvinyl Alcohol (PVA) Nanofiber Membranes via Green Electrospinning.

As an environmentally friendly water-soluble polymer, polyvinyl alcohol (PVA) has attracted extensive attention because of its non-toxic, degradable, low cost, and good biocompatibility. Electrospinning is a kind of nanotechnology, and the nanofiber membrane prepared by it has the advantages of large surface area-to-volume ratios, nano- to micron-sized fibers, etc. Herein, a simple and facile one-step green electrospinning method was developed to fabricate various environmentally friendly PVA nanofiber membranes. The lipophilic properties of PVA membranes were investigated and optimized according different PVA concentrations. The PVA electrospun fiber prepared from the solution at a concentration of 10 wt% had the highest adsorption capacity for the adsorption of new and waste engine oils, and the waste engine oil adsorption capacity (12.70 g/g) was higher than that of new engine oil (11.67 g/g). It also has a relatively large BET surface area (12.05 m2/g), a pore volume (0.04 cm3/g), and an appropriate pore diameter (13.69 nm) and fiber diameter (174.21 nm). All electrospun PVA membranes showed excellent lipophilic properties due to their oil contact angles of much less than 30°. Therefore, PVA electrospun fibrous membranes have great application potential in the field of purifying engine oil due to the excellent lipophilic properties and oil absorption capacity.

Electrospun Bi-doped SnO2 porous nanosheets for highly sensitive nitric oxide detection

The real-time monitoring of NO in the low-concentration range from the ppb- to ppm-level is of great importance in the field of healthcare; however, accomplishing this is still challenging owing to the technical issues regarding highly efficient and selective sensing materials. In this study, we demonstrate the highly sensitive and selective detection of NO by Bi-doped SnO2 two-dimensional ultrathin nanosheets with porous structures, fabricated using a facile one-step electrospinning method. It was found that the SnO2 with 0.75 mol% Bi exhibits the highest sensitivity of 217–10 ppm of NO at a relatively low temperature of 75 °C. Further, a low detection limit of 50 ppb; high selectivity; and good stability have also been achieved. Further detailed analysis indicates that the promising sensing properties can be attributed to the ultrathin nanosheet structure, which has a high surface area and abundant pores. These results indicate that 2D metal-oxide ultrathin nanosheets achieve superior gas-sensing performance, and Bi-doped SnO2 is a potential material for use in the real-time and low-power detection of NO.