Electrospun nanofibers of poly（vinyl pyrrolidone）/Eu^3＋ and its photoluminescence properties

Nanofibers of poly（vinyl pyrrolidone） （PVP）/Eu^3＋ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FT-IR）, and photoluminescence （PL）. The results indicated that, Eu^3＋ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu^3＋ hybrid nanofibers had favorable photoluminescence properties.     

Electrospun Sb2Se3@C nanofibers with excellent lithium storage properties

Antimony-based materials have become promising anodes within lithium-ion batteries(LIBs)due to their low cost and the high theoretical capacity.However,there is a potential to further enhance the electrochemical performance of such antimony-based materials.Herein,Sb2Se3@C nanofibers(Sb2Se3@CNFs)are designed and obtained via a novel electrospinning method.Upon electrochemically testing as an anode within LIBs,the Sb2Se3@CNFs(annealed at 600℃)delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles.Moreover,it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g.The excellent performance of the Sb2 Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials,but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion.The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.     

Electrospun nickel nanoparticles@poly(vinylidene fluoride-hexafluoropropylene) nanofibers as effective and reusable catalyst for H2 generation from sodium borohydride

Nickel nanoparticles (Ni NPs) supported on Poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers (PVDF-HFP NFs) were successfully synthesized through electrospinning and in-situ reduction of Ni²⁺ salts into the surface of PVDF-HFP NFs to form metallic Ni NPs@PVDF-HFP NFs. Different percentages of nickel acetate tetrahydrate (NiAc) (10 %, 20 %, 30 %, 40 % wt.) based PVDF-HFP. The formation of tiny metallic Ni NPs @PVDF-HFP membrane NFs was demonstrated using standard physiochemical techniques. Nanofibers membranes have demonstrated good catalytic activity in H₂ production from sodium borohydride (NaBH₄). The sample composed of 40 %wt Ni showed the highest catalytic activity compared to the other formulations. Whereas 103 mL of H₂, from the hydrolysis of 1.34 mmol NaBH₄, was produced using 40 wt% NiAc compared to 68 mL, 81 mL, and 93 mL for 10 wt%, 20 wt%, and 30 wt% NiAc, respectively, in 60 min at 25 °C. The hydrogen generation has been enhanced with an increase in the Nanofibers membrane amount and reaction temperature. The latter results in a low activation energy (23.52 kJ mol^?1). The kinetics study revealed that the reaction was pseudo-first-order in sodium borohydride concentration and catalyst amount. Furthermore, the catalyst exhibits satisfactory stability in the hydrolysis process for ten cycles. Because of its easy recyclability, the introduced catalyst has a wide range of potential applications in the generation of H₂ from sodium borohydride hydrolysis.     

电纺纳米纤维多级形貌调控研究进展

"静电纺丝"是目前制备纳米级纤维最为简单有效的方法,其制得的纤维材料具有径细、质轻、比表面大、孔隙率大等优点,应用前景广泛。与传统纤维相比,电纺纤维具有一些独特的形貌结构特点。本文根据电纺纤维的宏观、微观形貌特征将其划分为三级形态(多根纳米纤维排列形成的聚集形貌)、二级形态(单根纳米纤维的宏观形貌)以及一级形态(单根纳米纤维的介观及微观形貌),详述了各级形态纤维的形貌结构特点、制备方法以及形成机理,并对这些形态各异纤维材料的应用前景进行了展望。     

Enhancement in the photocatalytic activity of TiO2 nanofibers hybridized with g-C3N4 via electrospinning

TiO₂/g-C₃N₄ nanofibers with diameter of 100–200 nm were prepared by electrospinning method after calcination at high temperature, using polyvinylpyrrolidone (PVP), Melamine (C₃H₆N₆), Ti(OC₄H₉)₄ as raw materials. The composite nanofibers were characterized by XRD, FT-IR, SEM, UV–vis and PL respectively. The effects of different g-C₃N₄ contents on structure and photocatalytic degradation of the composite nanofibers were investigated. The results indicated that with increasing g-C₃N₄ content, the diameter of the composite fibers increased and the morphology changed from uniform structure to a nonuniform one, containing beads. The composite nanofibers displayed the best photocatalytic degradation on RhB, when the g-C₃N₄ content was 0.8 wt%. The degree of degradation was up to 99% at the optimal conditions of 40 min. The degradation activity of the composite nanofibers on RhB, MB and MO was found to be higher than that of the TiO₂ nanofibers.     

Electrospun polymer nanofibers as a solid-phase extraction sorbent for the determination of trace pollutants in environmental water

This paper describes the novel preparation of three kinds of nanofibers [poly(styrene-co-methacrylic acid), poly(styrene-co-p-styrene sulfonate), polystyrene] investigated as solid-phase extraction (SPE) sorbents to extract six compounds (nitrobenzene, 2-naphthol, benzene, n-butyl p-hydroxybenzoate, naphthalene, p-dichlorobenzene) in environmental water by high-performance liquid chromatography. Parameters affecting extraction efficiency were investigated in detail to explore the extraction mechanism of the nanofibers. Under optimized conditions, six compounds followed an excellent linear relationship in the range 10–5,000 ng mL⁻¹ with coefficients of determination (r ²) greater than 0.99. The repeatability (expressed as relative standard deviations) was from 3.0 to 7.0%, corresponding to 2.0 mL of water samples at 25 and 500 ng mL⁻¹ spiked levels for the six compounds. The limits of detection varied from 0.01 to 0.15 ng mL⁻¹ (signal-to-noise ratio of3). A comparison of the SPE using nanofibers as sorbents and the most commonly used octadecylsilica SPE cartridges was carried out in terms of absolute recovery, sensitivity, and reproducibility for the compounds investigated. Finally, the method was applied to four real water samples. The results highlighted the importance of functional groups, and the polarity of nanofibers in controlling sorption of target compounds, and clearly showed that the new method could be a viable and environmentally friendly technique for analyzing pollutants in environmental samples.     

聚丙烯腈电纺纤维的功能化

聚丙烯腈是一种性能优异、应用广泛的成纤聚合物,静电纺丝技术则可用于制备聚丙烯腈纳米纤维,本文对聚丙烯腈纳米纤维的功能化进行了综述.通过表面仿生修饰、碳纳米管填充等方法改性的聚丙烯腈电纺纤维被尝试作为酶固定化的载体材料,在显著提高载酶量的同时,能大幅度提高酶活性.糖基功能化的纳米纤维对特定的蛋白质具有较高的识别效率,可望用于蛋白质的分离与纯化.卟啉化的聚丙烯腈电纺纤维则在显示出荧光特性的同时,在催化、传感等方面具有潜在的应用前景.     

铜掺杂氧化锌纳米纤维宽线性响应乙醇气体传感器

采用电纺丝技术结合高温煅烧制备了铜掺杂氧化锌复合纳米纤维,并通过XRD,XPS,SEM和TEM等手段对材料进行表征.将所得材料作为敏感层构筑了气体传感器,器件对乙醇蒸气具有很好的传感特性,特别是当Cu/Zn摩尔比为1∶60时,由于Cu组分的活化作用,所得传感器不仅具有高灵敏度、快速响应恢复(2 s/7 s)特性及优良的稳定性,而且在5~104μg/g超大乙醇蒸气浓度范围内都能保持良好的线性关系(R2=0.99),这不仅有利于乙醇实际检测,而且对宽响应范围及高灵敏传感器的发展具有重要意义.     

Thermo-mechanical behavior of electrospun thermoplastic polyurethane nanofibers

Analysis of the thermo-mechanical behavior of electrospun thermoplastic polyurethane (TPU) block co-polymer nanofibers (glass transition temperature ∼−50 °C) is presented. Upon heating, nanofibers began to massively contract, at ∼70 °C, whereas TPU cast films started to expand. Radial wide-angle X-ray scattering (WAXS) profiles of the nanofibers and the films showed no diffraction peaks related to crystals, whereas their amorphous halo had an asymmetric shape, which can be approximated by two components, associated with hard and soft segments. During heating, noticeable changes in the contribution of these components were only observed in nanofibers. These changes, which were accompanied with an endothermic DSC peak, coinciding with the start of the nanofibers contraction, can be attributed to relaxation of an oriented stretched amorphous phase created during electrospinning. Such structure relaxation becomes possible when a portion of the hard segment clusters, forming an effective physical network, is destroyed upon heating.     

A review of opportunities for electrospun nanofibers in analytical chemistry

Challenges associated with analyte and matrix complexities and the ever increasing pressure from all sectors of industry for alternative analytical devices, have necessitated the development and application of new materials in analytical chemistry. To date, nanomaterials have emerged as having excellent properties for analytical chemistry applications mainly due to their large surface area to volume ratio and the availability of a wide variety of chemical and morphological modification methods. Of the available nanofibrous material fabrication methods, electrospinning has emerged as the most versatile. It is the aim of this contribution to highlight some of the recent developments that harness the great potential shown by electrospun nanofibers for application in analytical chemistry. The review discusses the use of electrospun nanofibers as a platform for low resolution separation or as a chromatographic sorbent bed for high resolution separation. It concludes by discussing the applications of electrospun nanofibers in detection systems with a specific focus on the development of simple electrospun nanofiber based colorimetric probes.     

Selective fabrication of porous iron oxides hollow spheres and nanofibers by electrospinning for photocatalytic water purification

Porous hematite (α-Fe₂O₃) hollow spheres and nanofibers could be obtained via electrospinning and subsequent thermal decomposition in air. The precursor could be fabricated by electrospinning using Fe(NO₃)₃ as the iron source and Polyvinylpyrrolidone (PVP) as a complexing reagent. Upon calcination, pure porous α-Fe₂O₃ hollow spheres and nanofibers could be obtained at 650 °C for 3 h. The novel hollow spheres have an abundantly porous structure as well as large surface areas. Benefitting from the special porous structure, narrow bandgap, and higher surface area, porous α-Fe₂O₃ hollow materials are used as visible-light-responsive photocatalysts. So we have investigated the visible light photodegradation behavior of porous hematite (α-Fe₂O₃) hollow spheres and nanofibers towards organic dyes, as Rhodamine B (RhB). The synergetic effects of higher surface area, pore structures promoted the photocatalytic efficiency for RhB degradation under visible light and contributed to achieving the enhanced and stable photocatalytic activity.     

Glucose Biosensor Using Glucose Oxidase and Electrospun Mn2O3‐Ag Nanofibers

The highly porous Mn₂O₃‐Ag nanofibers were fabricated by a facile two‐step procedure (electrospinning and calcination). The structure and composition of the Mn₂O₃‐Ag nanofibers were characterized by SEM, TEM, XRD, EDX and SAED. The as‐prepared Mn₂O₃‐Ag nanofibers were then employed as the immobilization matrix for glucose oxidase (GOD) to construct an amperometric glucose biosensor. The biosensor shows fast response to glucose, high sensitivity (40.60 µA mM^?1 cm^?2), low detection limit (1.73 µM at S/N=3), low K_m,app value and excellent selectivity. These results indicate that the novel Mn₂O₃‐Ag nanfibers‐GOD composite has great potential application in oxygen‐reduction based glucose biosensing.     

Electrospinning and characterization of medium-molecular-weight poly(vinyl alcohol)/high-molecular-weight poly(vinyl alcohol)/montmorillonite nanofibers

Submicron fibers of medium-molecular-weight poly(vinyl alcohol) (MMW-PVA), high-molecular-weight poly(vinyl alcohol) (HMW-PVA), and montmorillonite clay (MMT) in aqueous solutions were prepared by electrospinning technique. The effect of HMW-PVA and MMT on the morphology and mechanical properties of the MMW-PVA/HMW-PVA/MMT nanofibers were investigated for the first time. Scanning electron microscopy, viscometer, tensile strength testing machine, thermal gravimetric analyzer (TGA), and transmission electron microscopy (TEM) were utilized to characterize the PVA/MMT nanofibers morphology and properties. The MMW-PVA/HMW-PVA ratios and MMT concentration played important roles in nanofiber's properties. TEM data demonstrated that exfoliated MMT layers were well distributed within nanofibers. It was also found that the mechanical property and thermal stability were increased with HMW-PVA and MMT contents.     

静电纺丝法制备硼掺杂氧化硅纳米纤维用于低碳烷烃氧化脱氢制烯烃

乙烯和丙烯等低碳烯烃是重要的基础有机化工产品,广泛应用于化工生产的各个领域.相比于其他工艺,低碳烷烃氧化脱氢制烯烃工艺具有不受热力学平衡限制、无积炭等特点而被广泛研究.近年发现六方氮化硼(h-BN)、硼化硅(SiB6)和磷酸硼(BPO4)等非金属硼基催化剂能够高效催化烷烃氧化脱氢反应,并抑制产物烯烃的过度氧化,表现出高的催化活性和烯烃选择性.大量的研究表明,硼基催化剂活性起源于催化剂表面的"BO"物种(如B-O和B-OH等基团).氧化硼(B2O3)作为一种氧化气氛中化学性质稳定的含硼化合物,兼具丰富的"BO"位点,在反应条件下可形成多种结构以适用不同的化学环境,为制备高效的烷烃氧化脱氢催化剂提供了可能.在之前的研究中,多将B2O3浸渍在常规的TiO2,SiO2,A12O3等三维多孔载体上用于氧化脱氢反应.考虑到B2O3结构的灵活性和易于成键特性,需开发更为有效的合成策略,以提升B2O3催化剂在氧化脱氢反应中的活性和稳定性.本文采用静电纺丝技术合成了直径为100～150 nm的多孔掺硼二氧化硅纳米纤维(PBSN)用于低碳烷烃氧化脱氢反应.静电纺丝法合成的催化剂中硼物种在开放的氧化硅纤维骨架上均匀分散且稳定固载.一维纳米纤维结构不仅有利于扩散,且赋予催化剂在高重时空速(WHSV)条件下优异的烷烃氧化脱氢反应活性.在乙烷氧化脱氢反应中,当乙烷的转化率达到44.3％时,乙烯的选择性和产率分别为84％和44.2 μmol gcat-1 s-1.而在丙烷脱氢反应中,当丙烷转化率为19.2％时,总烯烃选择性及丙烯产率分别为90％和76.6 μmol gcat-1 s-1.在温度为545 ℃,丙烷WHSV高达84.6 h-1的条件下,催化剂保持长时间稳定.与其他负载型氧化硼催化剂相比,PBSN催化剂具有更高的烯烃选择性和稳定性.研究表明,在氧化硅负载B2O3催化剂催化丙烷氧化脱氢反应中,载体中Si-OH基团的存在可能会降低丙烯的选择性.瞬态分析和动力学实验表明,硼基催化剂催化烷烃氧化脱氢反应过程中O2的活化受到烷烃的影响.本文不仅为高效硼基催化剂的合成提供了新思路,也为深入理解该类催化剂上烷烃氧化脱氢反应过程提供了实验支撑.     

Parameter study and characterization for polyacrylonitrile nanofibers fabricated via centrifugal spinning process

Electrospinning is currently the most popular method for producing polymer nanofibers. However, the low production rate and safety concern limit the practical use of electrospinning as a cost-effective nanofiber fabrication approach. Herein, we present a novel and simple centrifugal spinning technology that extrudes nanofibers from polymer solutions by using a high-speed rotary and perforated spinneret. Polyacrylonitrile (PAN) nanofibers were prepared by selectively varying parameters that can affect solution intrinsic properties and operational conditions. The resultant PAN nanofibers were characterized by SEM, and XRD. The correlation between fiber morphology and processing conditions was established. Results demonstrated that the fiber morphology can be easily manipulated by controlling the spinning parameters and the centrifugal spinning process is a facile approach for fabricating polymer nanofibers in a large-scale and low-cost fashion.     

Electrospun Mesoporous Poly(Styrene‐Block‐Methyl‐ Methacrylate) Nanofibers as Biosensing Platform: Effect of Fibers Porosity on Sensitivity

The present work demonstrates the use of mesoporous nanofibers for the enhanced analytical performance of electrochemical biosensor. By exploiting the phase separation property of the block copolymers, a simple three‐step process was used to generate the porosity in the nanofibers. Here we present the effect of the porosity on the sensing ability of the electrospun PS‐b‐PMMA nanofibers. The functional groups present on the nanofiber surface were characterized using DPV. The nanofibers modified electrode showed a large decrease in the oxidation current with the increase in the pH from 4.2 to 6.8 for the anionic redox couple whereas the change in the current is negligible for a neutral redox couple, this suggested the presence of ‐COOH groups. A one‐step process was used for the immobilization of biotin. There were about 35.5 % and 66.6 % decrease in the redox current for the as‐spun and porous nanofibers after functionalization respectively which indicate the presence of a high amount of active sites in the porous nanofibers. Finally, the sensor response was studied using streptavidin (1μg/ml–1fg/ml) as a model analyte. CV studies showed a 2.7‐fold increase whereas DPV showed a 6‐fold increase in the sensitivity for the porous nanofibers as compared to the as‐spun nanofibers.     

One-dimensional GdVO4:Ln (Ln=Eu, Dy, Sm) nanofibers: Electrospinning preparation and luminescence properties

One-dimensional GdVO₄:Ln³⁺ (Ln=Eu, Dy, Sm) nanofibers have been prepared by a combination method of sol-gel process and electrospinning technology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), quantum efficiency (QE), and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The XRD, FT-IR, and TG-DTA results show that GdVO₄:Ln³⁺ nanofibers samples crystallize at 700 °C. SEM images indicate that the as prepared precursor fibers are smooth. After being calcined at 700 °C for 4 h, the fibers still maintain their fiberlike morphology with rough surface. TEM image further manifests that the GdVO₄:Ln³⁺ nanofibers consist of nanoparticles. Under ultraviolet excitation and low-voltage electron beam excitation, GdVO₄:Ln³⁺ phosphors showed their strong characteristic emission due to an efficient energy transfer from vanadate groups to dopants. The optimum doping concentration of Ln³⁺ in the GdVO₄ nanofibers also has been investigated.     

Preparation and study of PPV/PVA nanofibers via electrospinning PPV precursor alcohol solution

We have found a simple method to prepare poly(phenylene vinylene) (PPV) nanofibers via electrospinning PPV precursor alcohol solution under annealed at 180 °C in a N₂ atmosphere. The nanofibers are uniform in diameter and long in decimeter magnitudes with resistance in decay, which makes them have potential applications in optical and electronic devices. The morphology can be better controlled by blend PPV precursor solution with poly(vinylalcohol) (PVA) aqueous solution. The fluorescence spectrum of PPV/PVA nanofibers exhibited appreciable blue shift, which made it possible to fabricate nanofibers with fluorescence from yellow-green to blue.     

Electrospun palladium (IV)-doped copper oxide composite nanofibers for non-enzymatic glucose sensors

Pd (IV)-doped CuO oxide composite nanofibers (PCNFs) have been successfully fabricated via electrospinning and then employed to construct an amperometric non-enzymatic glucose sensor. The PCNFs based glucose sensors display distinctly enhanced electrocatalytic activity towards the oxidation of glucose, showing significantly lower overvoltage (0.32 V) and ultrafast (1 s) and ultrasensitive current (1061.4 μA mM⁻¹ cm⁻²) response with a lower detection limit of 1.9 × 10⁻⁸ M (S/N = 3). Additionally, excellent selectivity, reproducibility and stability have also been obtained. These results indicate that PCNFs are promising candidates for amperometric non-enzymatic glucose detection.     

Methyldichlorosilanes with fluorinated cyclic substituents at silicon

Methyldichlorosilanes with fluorinated cyclic substituents at silicon are prepared by the reaction of hydrosilylation of the corresponding hexafluoroolefins with methyldichlorosilane.