Single-spinneret Electrospinning Research Articles

Preparation of MoP-based quasi-two-dimensional belt-like composite fibers and its performance modulation for sodium/potassium ion storage

Beyond round nanofibers, electrospinning method is able to fabricate thin fibers with various cross-sectional shapes. In this work, using phosphomolybdic acid to trigger the polymerization reaction of pyrrole with addition of tin salt for the filler of carbon fibers, we prepared quasi-two-dimensional thick belt-like fibers through single spinneret electrospinning. The side-by-side welding nanofiber bundles with dog-bone-shaped cross-section improved the connection between fibers, endowing the fiber films with some flexibility and enabling it to be used as freestanding electrode. Employed as anode for sodium/potassium ion storage, the carbon fiber encapsulated MoP/SnO2 material exhibited promising electrochemical performance. Controlling the collection process of electrospinning, the electrode mass loading can be increased to 10 mg cm−2. Combined with surface selenizing modification, the performance of as-prepared MoP/SnO2/MoSe2 was further improved, which exhibited areal capacity about 1.5 mAh cm−2 as anode for sodium/potassium ion storage with mass loading of 8–9 mg cm−2.

Electrospun Fibers of Biocompatible and Biodegradable Polyesters, Poly(Ethylene Oxide) and Beeswax with Anti-Bacterial and Anti-Fungal Activities

Fibrous materials composed of core–sheath fibers from poly(ethylene oxide) (PEO), beeswax (BW) and 5-nitro-8-hydroxyquinoline (NQ) were prepared via the self-organization of PEO and BW during the single-spinneret electrospinning of a homogeneous blend solution of the partners. Additionally, the application of the same approach enabled the preparation of fibrous materials composed of core–double sheath fibers from PEO, poly(L-lactide) (PLA) and NQ or 5-chloro-7-iodo-8-hydroxyquinoline (CQ), as well as from PEO, poly(ε-caprolactone) (PCL) and NQ. The consecutive selective extraction of BW and of the polyester with hexane and tetrahydrofuran, respectively, evidenced that core–double sheath fibers from PEO/polyester/BW/drug consisted of a PEO core, a polyester inner sheath and a BW outer sheath. In order to evaluate the possibility of the application of fibrous materials from PEO/BW/NQ, PEO/PLA/BW/NQ, PEO/PCL/BW/NQ and PEO/PLA/BW/CQ for plant protection, microbiological studies were performed using both phytopathogenic microorganisms (Pseudomonas corrugata, Fusarium graminearum and Fusarium avenaceum) and beneficial microorganisms (Pseudomonas chlororaphis, Bacillus amyloliquefaciens and Trichoderma asperellum). It was found that the fibrous materials had anti-bacterial and anti-fungal activity against both phytopathogenic and beneficial microorganisms. This is the first report on the activity of fibrous materials loaded with 8-hydroxyquinoline derivatives not only against phytopathogenic but also against beneficial microorganisms that are of importance in agriculture.

Enhanced acetone sensing properties of W-doped ZnFe2O4 electrospinning nanofibers

Acetone not only harms the human body but is also considered a diabetes biomarker. A series of acetone-sensitive W-doped ZnFe2O4 composite nanofibers were successfully prepared in this study using a simple single-spinneret electrospinning method and a 600 °C calcination treatment. The crystalline phase, morphology, and elemental composition of ZnFe2O4 nanofibers with varying levels of W doping were systematically characterized and analyzed. The gas-sensitive sensing properties of the nanofibers were also thoroughly investigated. The results demonstrate that W is successfully doped into the ZnFe2O4 lattice, leading to a significant reduction in the crystallite size that composes the nanofibers and the formation of Fe2O3 olive-shaped nanoparticle embellishments on the surface of nanofibers. Meanwhile, the generation of heterojunctions and reduction of crystallite size significantly enhance the sensitivity and selectivity of ZnFe2O4 to acetone vapor. The sensors based on 6 mol% W-doped ZnFe2O4 composite nanofibers, in particular, exhibit a response of up to 1.95 for 0.125 ppm acetone vapor at 200 °C. Finally, a comprehensive examination of the acetone sensing mechanism of W-doped ZnFe2O4 is performed, as well as the potential causes for morphological changes and heterojunctions to improve the gas-sensitive performance of ZnFe2O4.

Core/Double-Sheath Composite Fibers from Poly(ethylene oxide), Poly(L-lactide) and Beeswax by Single-Spinneret Electrospinning.

The conventional approach for preparation of core-sheath fibers is coaxial electrospinning. Single-spinneret electrospinning of emulsions is a much less common method to obtain core-sheath fibers. Core-sheath structure may be generated by electrospinning of homogeneous blend solutions; however, reports on such cases are still scarce. Herein, the preparation of nanofibrous composites from poly(ethylene oxide) (PEO), poly(L-lactide) (PLA) and beeswax (BW) by single-spinneret electrospinning of their homogeneous blend solutions in chloroform is reported. The produced fibers had core/double-sheath structure with a PEO core, PLA inner sheath and BW outer sheath. This original fiber structure was evidenced by transmission electron microscopy, selective extraction of BW or PEO, and X-ray photoelectron spectroscopy. The PLA/BW double sheath led to hydrophobicity of the PEO/PLA/BW mats. The tensile tests revealed that PEO/PLA/BW mats had substantially improved mechanical behavior as compared to PEO, PLA and PEO/BW mats. PEO/PLA/BW mats can be used as drug carriers as evidenced by the one-pot incorporation of the model drug 5-nitro-8-hydroxyquinoline (NQ) into the fibrous materials. Microbiological tests showed that PEO/PLA/BW/NQ had antimicrobial activity. Therefore, the new materials are promising for wound healing applications.

Surface oxygen vacancies promoted Pt nanoparticles on celery-like CeO2 nanofibers for enhanced sinter-resistance and catalytic performance

Supported metal nanoparticles hold great promise for heterogeneous catalysis but are greatly persecuted by the poor thermal stability upon high temperatures. In this work, we facilely synthesized intriguing celery-like CeO2 nanofibers with high surface areas and hierarchical pores and channels by single-spinneret electrospinning. The nanofibers were explored as reliable support for polyvinylpyrrolidone (PVP)-stabilized Pt nanoparticles, followed by activation at 350 °C in N2 to eliminate PVP stabilizer and generate sufficient surface oxygen vacancies. Therefore, the resultant Pt@CeO2 was endowed with enhanced metal−support interaction and thereby promoted sinter-resistance. In this case, the Pt@CeO2 exhibited over six times higher activity after aging at 600 °C toward the hydrogenation of p-nitrophenol than that of PtPVP/CeO2. Moreover, the thermal-stable Pt@CeO2 significantly decreased the activation energy of soot oxidation from 178.0 kJ/mol to 109.4 kJ/mol, due to the abundant oxygen vacancies, as well as the promoted solid–solid contact by the interconnected and celery-like CeO2 nanofibers. After such a sinter-promoting exothermic reaction, the supported Pt nanoparticles maintained a small size of 5.78 nm. This approach provides a facile method to prepare noble metal catalysts with both high atom economy and sinterresistance.

Core-Sheath-Like Poly(Ethylene Oxide)/Beeswax Composite Fibers Prepared by Single-Spinneret Electrospinning. Antibacterial, Antifungal, and Antitumor Activities.

Composite fibrous materials are prepared from poly(ethylene oxide) (PEO) and beeswax (BW) by single-spinneret electrospinning using chloroform as a common solvent. The obtained fibers have core-sheath-like structure, as evidenced by the water contact angle values and corroborated by the results on the elemental composition of the fiber's surface determined by X-ray photoelectron spectroscopy (XPS) and by analyses with scanning electron microscopy of fibers before and after selective extraction of PEO or BW. Furthermore, the core-sheath-like structure is proven by transmission electron microscopy. This is attributed to self-assembly of BW molecules on the surface of the formed fibers driven by the incompatibility between PEO and BW. 5-Nitro-8-hydroxyquinoline (NQ) is embedded as a model drug with antibacterial, antifungal, and anticancer properties in the PEO/BW fibrous materials. XPS analyses reveal that NQ is present on the surface of the PEO/BW/NQ materials. Using a purposely designed cell for fixation of the fibrous materials the NQ release in phosphate buffer solution with рН 7.4 is followed. The new PEO/BW/NQ fibrous materials exhibit antibacterial activity against S. aureus and E. coli, antifungal effect against C. albicans, and selective anticancer activity against HeLa (human cervical adenocarcinoma cells) and SH-4 (human melanoma cells) cell lines.

Form-stable phase change materials based on hierarchically channel-like silica nanofibrous mats for thermal energy storage

Hierarchical channel-like SiO2 nanofibrous mats were prepared via microemulsion electrospinning in combination with calcination for thermal energy storage. The interior channel number of SiO2 nanofibers was flexibly regulated by tuning the proportion of continuous phase to dispersion phase. Microemulsion electrospinning, as a method of single-spinneret electrospinning, makes it versatile, simple and convenient for the preparation of hierarchical SiO2 nanofibers with multi-channel structure and high porosity. Quinary fatty acid eutectics were encapsulated in multi-channel SiO2 mats to obtain form-stable phase change materials (FSPCMs). The results indicated the crystallization enthalpy and melting enthalpy of as-fabricated FSPCMs could be up to 115.7 and 112.9 J·g−1, respectively. After 40 thermal cycles, there is no significant difference for the phase change temperature and enthalpy of FSPCMs, revealing outstanding thermal cycling stability. The study proves that microemulsion electrospinning is exactly a straightforward and universal method to fabricate the supporting substance of FSPCMs.

Preparation of Li+:TiO2 nanowires, Li4Ti5O12 nanotubes, and a Li4Ti5O12 nanotube/graphene composite by single-spinneret electrospinning for application in a lithium-ion battery

A single-spinneret electrospinning method to fabricate Li4Ti5O12 nanotubes and a Li4Ti5O12 nanotube/graphene composite was reported.

Synthesis and Transformation of Hollow Rutile Titania Wires by Single Spinneret Electrospinning with Sol-Gel Chemistry

The work described below was carried out to understand how to control the morphology of nanostructured titania calcined from electrospun nanofibers. This is the first report of hollow rutile nanofibers synthesized from electrospun nanofibers with short calcination time. Titanium isopropoxide was incorporated into the nanofibers as the titania precursor. The electrospinning technique was used to fabricate ceramic/polymer hybrid nanofibers. The electrospun nanofibers were then calcined to produce rutile titania nanofibers with different morphologies (hollow or solid nanofibers), which were characterized by SEM and TEM. The initial concentration of ceramic precursor and the calcination time were shown to control the morphology of the nanofiber. The hollow morphology was only obtained with a concentration of the precursor within a certain level and with short calcination times. The heat treatment profile contributed to particle growth. At longer times, the particle growth led to the closure of the hollow core and all the nanofibers resembled strings of solid particles. A formation mechanism for the hollow nanofibers is also proposed.

Preparation and Characterization of Hollow Zinc Oxide Nanofibers and Investigation of Its Photocatalytic Properties

Hollow inorganic nanofibers have great potential application in the field of photocatalysis due to their special three-dimensional structure. In our work, we have fabricated ZnO hollow nanofibers (ZnO-HNF) by simple single-spinneret electrospinning of polyacrylonitrile (PAN)/zinc acetate precursor solution, followed by stepwise annealing at 300–500 °C. The results show that long and continuous ZnO-HNF with shell consisting of uniform compacted ZnO nanoparticles are successfully fabricated, and the shell thickness is approximately 30 nm. The formation mechanism of ZnO-HNF is speculated to be consequence of the different rate of mass diffusion during the annealing process (Kirkendall effect). The prepared Zn-HNF exhibits good performance in photocatalysis. The photocatalytic removal efficiency of Rhodamine B (RhB) under ultraviolet light irradiation can reach 94.08% in 1 hour, and the removal efficiency of Cr(VI) is 94.49% in 2 hours. This work provides new ideas for the development of ZnO in the field of photocatalysis, and provides new possibilities for more types of subsequent photocatalytic materials.

Constructing fibril-in-tube structures in ultrathin CeO2-based nanofibers as the ideal support for stabilizing Pt nanoparticles

The intriguing one-dimensional (1D) nanofibers with secondary structures (e.g., hollow, core-sheath, fiber-in-tube) have attracted much attention for their unique open structure, high surface area, and hierarchical pore structure. This work utilized single-spinneret electrospinning to construct mesoporous CeO2-based ultrathin nanofibers with a new fibril-in-tube morphology. The intriguing fibril-in-tube structure within Al2O3/CeO2 nanofibers was achieved by carefully selecting two different metal precursors with different decomposition rates upon calcination. The use of Al(acac)3 as Al2O3 precursor, which rapidly releases gaseous pieces and leads to the growth kinetics varied along the radial direction of nanofibers, is critical to the formation of fibril-in-tube structure. The new CeO2 nanofibers with different amount of Al2O3 endowed with homogenous elemental distribution and were explored as reliable metal supports toward stabilizing Pt nanoparticles under harsh aging. This inspiring result was ascribed to an energy barrier established by reducible (CeO2) and non-reducible oxide (Al2O3), strong metal-support interaction between Pt and CeO2, as well as the physical confinement caused by the fibril-in-tube structure. The resultant new catalytic system (referred to Pt@Al2O3/CeO2) displayed good sinter-resistant performance and exhibited 13-times great catalytic activity than that of Pt@Al2O3 catalyst after harsh aging at 700 °C toward the hydrogenation of p-nitrophenol.

CoFe2/BaTiO3 Hybrid Nanofibers for Microwave Absorption

CoFe2/BaTiO3 hybrid nanofibers (CoFe2/BTO HNFs) have been synthesized via a simple single-spinneret electrospinning followed by a calcination and hydrogen-thermal reduction process for microwave ab...

In2O3 Hierarchical Structures of One-Dimensional Electrospun Fibers with in Situ Growth of Octahedron-like Particles with Superior Sensitivity for Triethylamine at Near Room Temperature

A one-step single-spinneret electrospinning method is used to prepare tunable In2O3 hierarchical structures of one-dimensional electrospun fibers with in situ growth of octahedron-like particles, a...

Morphology-activity correlation of electrospun CeO2 for toluene catalytic combustion

Herein, CeO2 catalysts with nanotube, nanobelt, and wire-in-nanotube morphologies were successfully fabricated by a facile single spinneret electrospinning technique. And catalytic activity of these electrospun CeO2 nanomaterials were evaluated by toluene catalytic combustion reaction. Among the three morphologies of CeO2 catalysts, CeO2 nanobelt (CeO2-NB) presented the best toluene catalytic combustion performance (T90% = 230 °C) at WHSV = 60,000 mL g−1 h−1, also exhibited the lowest activation energy (Ea = 80.2 kJ/mol). Based on the characterization by TEM, XRD, BET, SEM, XPS, Raman spectroscopy, H2-TPR, and O2-TPD results, the high catalytic activity of CeO2-NB catalyst was attributed to its porous nanobelt morphology with larger specific surface area and the abundance of surface oxygen vacancies. Furthermore, the CeO2-NB catalysts presented an excellent durability by longtime on-stream test (as well as presence of 5% vol. water vapor), suggesting its great potential for practical air pollution control application.

Multilevel Effective Heterojunctions Based on SnO2/ZnO 1D Fibrous Hierarchical Structure with Unique Interface Electronic Effects.

One-step single-spinneret electrospinning synthesis of 1D fibrous hierarchical structure can not only prevent the agglomeration or restacking of fibers or particles and enlarge surface active area but also promote the directional migration of electrons in materials and achieve effective regulation of resistances. Herein, tunable SnO2 and SnO2/ZnO fibrous hierarchical structures with in situ growth of monodisperse spherical-like particles on surface provide a new sight for adjusting component distribution, surface absorption and chemical reaction, electronic transmission path, and electron transfer efficiency. Compared with SnO2 porous fibers and SnO2 hierarchical structures, the optimal SnO2/ZnO sensors exhibit superior gas-sensing response value of 366-100 ppm ethanol at 260 °C as well as excellent gas selectivity and long-term stability, in which the enhanced gas-sensing mechanism is primarily derived from multilevel effective heterojunctions with unique interface electronic effects. Especially, these SnO2-based sensors can achieve favorable linear relationship of the response and gas concentration for sensitive trace detection in cosmetics for the first time, providing a new strategy to design composite materials for quantitative analysis of volatiles in the cosmetics evaluation process.

Electrospun MnxCo0.5−xSn0.5O2 and SnO2 porous nanofibers and nanoparticles as anode materials for lithium-ion battery

The specific capacity (781 mAh g−1) of SnO2 as anode materials for lithium-ion batteries (LIBs) is much higher than that of commercial graphite materials (372 mAh g−1), which attracts great attention from researchers. In this paper, a series of MnxCo0.5−xSn0.5O2 (x = 0.00, 0.15, 0.25, 0.35, 0.50) and SnO2 porous nanofibers and nanoparticles are prepared through a single-spinneret electrospinning technique followed by a calcination process. The electrochemical properties of porous nanofibers and nanoparticles have been measured and discussed, and the results show that porous nanofibers have better performance when doped with manganese and cobalt components. With the increase of manganese contents, the electrochemical capability of the batteries is improved. As a demonstration, the Mn0.50Co0.00Sn0.5O2 (x = 0.50) porous nanofibers present the first discharge capacity of 1347.3 mAh g−1, and after 100 cycles, Mn0.50Co0.00Sn0.5O2 possesses the higher discharge capacity of 131.6 mAh g−1 when compared with the other materials.

Preparation of novel form–stable composite phase change materials with porous silica nanofibrous mats for thermal storage/retrieval

Electrospun SiO2 nanofibrous mats have been widely utilized as substrate of form-stable phase change materials due to large specific surface area and high convection coefficient. In order to overcome the brittleness and enhance the absorption capacity of SiO2 nanofibrous mats as substrate, flexible and hollow SiO2 nanofibrous mats were prepared by single-spinneret electrospinning which eliminated complicated spinneret and unstable structure compared with coaxial electrospinning. Quinary fatty acid eutectics were chosen as representative fatty acid which were adsorbed in SiO2 nanofibrous mats to form form-stable phase change materials. The results showed that hollow structure can be observed as the content of paraffin oil decreased from 1.67 to 0.70 g, and as-prepared hollow nanofibrous mats displayed favorable flexibility. DSC results demonstrated that the largest melting/crystallization enthalpy supported by hollow SiO2 nanofibrous mats was approximately 123.80/120.50 J g−1, which was much higher than solid SiO2 nanofibers. More importantly, after 30 cycles, there was no obvious change for phase change temperature and enthalpy. The thermal conductivity of representative form-stable phase change materials was over three times than that of quinary fatty acid eutectics. Hence, flexible and hollow SiO2 nanofibrous mats were excellent substrate in form-stable phase change materials and would have wide application prospects.

Tube-in-tube composite nanofibers with high electrochemistry performance in energy storage applications

As a kind of excellent structure, nanotubes are combined with the advantages of the hollow structure and one-dimensional structure. Especially, the metal oxide nanotubes have broad application prospects in the field of energy storage and conversion. In this paper, we design a simple method to synthesize 12 kinds of carbon-coated tube-in-tube composite nanofibers (TiTCNFs) via a single-spinneret green electrospinning and subsequent pyrolysis processes, including carbon-coated metal TiTCNFs (Ni@C), carbon-coated single metal oxides TiTCNFs (Fe3O4@C, NiO@C, Co3O4@C, Mn3O4@C, CuO@C) and carbon-coated binary metal oxides TiTCNFs (CoFe2O4, CoMn2O4, MnFe2O4, NiCo2O4, NiFe2O4, NiMn2O4). The carbon-coated metal oxides TiTCNFs have superior electrochemical performances in Li-ion batteries and supercapacitors compared with hollow nanotube and pea-like structured composite nanofibers. The good electrochemical performances of TiTCNFs ascribe to the moderate carbon content, large specific surface area, and unique tube-in-tube structure effectively relieving the volume effect during the cycling process. The design and synthetic strategy is available for fabricating a wide variety of carbon-coated metal oxide nanotubes.

Pressure and Fluorescence Dual Signal Readout CuO-NiO/C Heterojunction Nanofibers-Based Nanoplatform for Imaging and Detection of Target Cancer Cells in Blood

The development of multifunctional nanoplatform, which integrates biosensing and imaging diagnosis, for accurate identification of cancer cells in blood or other bodily fluids is critical for early cancer diagnosis and treatment. Herein, by using a facile single spinneret electrospinning technique followed by thermal treatment, CuO-NiO/C heterojunction nanofiber was synthesized. The resultant CuO-NiO/C nanofibers exhibited excellent catalytic activity toward ammonia borane (AB) hydrolysis, producing a marked pressure increase in a closed reaction vessel. Moreover, the resultant nanofibers showed highly efficient catalytic activity for reduction of rhodamine 6G (Rh6G, fluorescent molecule), accompanied by the fluorescence quenching. On the basis of these findings, a novel sensing platform utilizing folic-acid (FA) conjugated CuO-NiO/C nanofibers as an artificial enzyme and recognition element for fluorescence imaging and pressure-based (pressure meter) detection of folate receptor (FR)-positive cancer cell...

Formation of MFe2O4 (M = Co, Mn, Ni) 1D nanostructures towards rapid removal of pollutants

Wire-in-tube and tube-in-tube structures have been prepared using single-spinneret electrospinning method through adjusting the preparation parameters of precursors and subsequent calcined process. Cobalt ferrite (CoFe2O4) samples revealed wire-in-tube morphology using a Co/Fe molar ratio of 1/2. In the case of other a Co/Fe molar ratio, belt and porous fiber morphologies were created. Manganese ferrite (MnFe2O4) sample exhibited tube-in-tube structure while nickel ferrite (NiFe2O4) sample just exhibited tube structure. Because of no template in electrospun polymer composite nanofibers, the precursor diffusion process during calcination plays an important role for morphology controlling. The magnetic properties of samples were examined. The cobalt ferrite (CoFe2O4) wire-in-tube sample revealed the highest saturation magnetization (60 emu/g). After growing with AlOOH on the surface, CoFe2O4 wire-in-tube sample revealed a high efficiency for the removal of Congo red pollutant. These nanostructures are particularly attractive for use in the field of nano-fluidic and nano-energy harvesting devices.