Bifunctional Nanofibers Research Articles

Electrospun Sulfonated Poly(ether ether ketone) and Chitosan/Poly(vinyl alcohol) Bifunctional Nanofibers to Accelerate Proton Conduction at Subzero Temperature.

Multilayered microstructures can accelerate the proton conduction process in proton exchange membranes (PEMs). Herein, we design and construct PEMs with microstructures based on bifunctional nanofibers and sulfonated poly(ether ether ketone) (SPEEK) nanofibers. Specifically, the bifunctional nanofibers composed of poly(vinyl alcohol) and chitosan are prepared and then combined with the electrospun SPEEK nanofibers. The stable microstructure is derived from the compatible interfacial property of nanofibers and the formed hydrogen bonds. The multilayered microstructure consisting of nanofibers accelerates the proton conduction even at subzero temperature because of regulating the proton conduction pathways. Specifically, the (SKNF/CPNF/SKNF)/PA membrane exhibits the proton conductivities of (0.951 ± 0.138) × 10-2 S/cm at -30 °C and (7.32 ± 0.37) × 10-2 S/cm at 160 °C. Additionally, the fine proton conductivity stability is demonstrated by the proton conductivity in the long-term test and the cooling/heating cycle test, such as 1.67 × 10-2 S/cm at -30 °C (after 1000 h), 4.52 × 10-2 S/cm at 30 °C (after 810 h), 1.12 × 10-2 S/cm at -30 °C, and 1.01 × 10-1 S/cm at 30 °C in the cooling/heating process (5 cycles). The single fuel cell possesses an open-circuit voltage of 0.886 V and a peak power density of 0.508 W/cm2 at 130 °C.

Constructing sandwich-like microstructure based on multi-nanofibers to accelerate proton conduction at subzero temperature

The well-ordered microstructure has been demonstrated to accelerate the proton conduction process through reducing proton conduction resistance. In this research, the proton exchange membranes (PEMs) with sandwich-like microstructure have been constructed based on Kevlar nanofibers and bifunctional nanofibers of chitosan (CS) with polyvinyl alcohol (PVA). The CS/PVA bifunctional nanofibers (CPNF) layer has been prepared with electrospinning process, which is stably adhered to the Kevlar nanofibers layer owing to compatible interfacial property. The fine structure stability without layer separation is achieved even with phosphoric acid (PA) molecules doping in the prepared PA doped composite membranes. The fibrous microstructure accelerats proton conduction through regulating proton conduction pathways. The objective of accelerating proton conduction at subzero temperature has been realized, reflecting in high and stable proton conductivities. For instance, the (Kevlar/CPNF/Kevlar)/PA membrane exhibits proton conductivities of 9.75 × 10−3 S/cm at −30 °C and 8.22 × 10−2 S/cm at 30 °C. Most importantly, the fine proton conductivity stability is identified by the results of the cycle test and long-term test. Specifically, the proton conductivities are respectively 8.62 × 10−3 S/cm at −30 °C and 8.07 × 10−2 S/cm at 30 °C after a five heating/cooling cycle process. The proton conductivities remain 2.97 × 10−2 S/cm at −25 °C and 7.19 × 10−2 S/cm at 30 °C after a 1032 h non-stop test. Additionally, the single proton exchange membrane fuel cell with the (Kevlar/CPNF/Kevlar)/PA membrane exhibits the peak power densities of 279.5 mW/cm2 at 100 °C and 352.7 mW/cm2 at 130 °C.

Highly efficient bifunctional nanofiber catalysts with 3D hierarchical nanostructures as building blocks for rechargeable Zn–air batteries

The well-distributed cobalt nanoparticles, coupled with the large specific surface area and high conductivity of the catalyst, expand the effective number of active sites to achieve high catalytic activity toward both the ORR and OER.

Simple, fast and eco-friendly micro-solid phase extraction based on thiol and ionic liquid bi-functional nanofibers membrane for the determination of sulfonamides in environmental water

BackgroundSulfonamides (SAs) are a class of synthetic antibacterial agents that are diffusely used in the medical industry and animal husbandry. Their prevalence in the influents and effluents of water treatment plants, as well as in rivers and groundwater, has provoked worldwide concern. Monitoring SAs in environmental water is of great significance for public health. However, most of the available detection techniques for SAs are cumbersome and time-consuming. With the increasing number of actual samples, simple, fast and environmentally friendly analytical methods are always in demand. ResultsHerein, we describe a highly efficient micro-solid phase extraction (μ-SPE) sample preparation technique based on a novel thiol and ionic liquid bi-functional nanofibers membrane (IL-SH-PAN NFsM) for multi-residue detection of sulfonamides (SAs) in water samples. By the synergistic effect of -SH and -IL, the as-prepared IL-SH-PAN NFsM demonstrated high adsorption capacity and excellent selectivity for SAs. The water samples can be directly used for μ-SPE without pH and ionic strength adjustment, and the eluent can be directly collected for HPLC-MS/MS analysis. Compared with other methods reported in the literature, this method required much shorter extraction time (2 min for a batch), much less amount of adsorbent (4.0 mg) and organic solvent (0.5 mL), while providing much higher sensitivity (1.4–3.9 ng L−1), and fine recoveries (88.8%–117.7%) with relative standard deviations less than 4.26%. Significance and noveltyA bi-functional nanofibers membrane was prepared for efficient extraction of SAs. The adsorbent exhibited superior adsorption performance and excellent selectivity. The underlying interaction mechanisms derived from -SH and -IL were proposed, which provide a new idea for preparing versatile adsorbents. Rapid, efficient and sensitive detection of SAs in water was achieved. The novel sample preparation technique can be expected as an efficient method for routine trace SAs residue monitoring in various water samples.

Simultaneous determination of multiple mycotoxins in corn and wheat by high efficiency extraction and purification based on polydopamine and ionic liquid bifunctional nanofiber mat

Due to the universality and harmfulness of mycotoxin co-contamination in cereals, it is of great significance to simultaneously monitor various mycotoxins co-polluted to ensure food safety and public health. In this work, a nanofiber mat modified by polydopamine and ionic liquid (PDA-IL-NFsM) was prepared and utilized as a solid-phase extraction (SPE) adsorbent for the simultaneous quantitative detection of multiple mycotoxins in corn and wheat. The PDA-IL-NFsM can form multiple retention mechanisms with the targets through hydrogen bond, π-π interaction, electrostatic or hydrophobic interaction, it shows favorable simultaneous adsorption performance (adsorption efficiency mostly higher than 88.27%) for fifteen mycotoxins in seven classes. Moreover, it can significantly reduce the matrix effect (lower than −13.69%), showing a good purification effect on the sample matrix. Based on the superior performance of PDA-IL-NFsM, a simple sample preparation method was established. The sample extract is simply diluted with water for SPE, and the eluent can be directly collected for ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis. The detection limit can reach 0.04–4.21 μg kg−1, the recovery was 80.09%–113.01%, and the relative standard deviations of intra-day and inter-day precision were 2.80%–14.81% and 0.68%–13.80% respectively. The results show that the proposed method has good sensitivity, accuracy and precision, and has practical application potential.

Functionalized polyvinyl alcohol nanofibers with visible light-triggered antibacterial and ethylene scavenging capabilities for food packaging

In this study, the sulfonated cobalt phthalocyanine-titanium dioxide P25 (CoPcTs-P25) nanoparticles were prepared by in situ synthesis and the samples were characterized using Fourier transform infrared spectroscopy, X-ray diffraction and UV–Vis spectroscopy. Biodegradable polyvinyl alcohol was selected as the backing material and CoPcTs-P25 was added as a visible-light ethylene scavenger and bacterial inhibitor, and PVA-CA@CoPcTs-P25 nanofiber films were prepared by electrospinning. In addition, the effects on ethylene degradation, bacterial survival and biocompatibility of the composite nanofiber were also evaluated. The photocatalytic degradation efficiency of PVA-CA@1.5%CoPcTs-P25 nanofibers for ethylene could reach 13.92% under visible light irradiation for 6 h. The nanofiber exhibited excellent antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), with a remarkable inhibition rate of over 90%. This bifunctional nanofiber demonstrated a new strategy for developing packaging materials and provided a broad prospect in fruits and vegetables preservation.

Construction of antibacterial photothermal PCL/AgNPs/BP nanofibers for infected wound healing

Infected wound healing remains a significant issue in clinical medicine and has attracted wide attention in the field of biomedical engineering. Although a range of bioactive materials have been developed, few provide sufficient antibacterial and pro-angiogenic effects for effective wound healing. Herein, we constructed a series of nanofibers (termed PL-n, n = 0, 1, and 2) based on polycaprolactone (PCL), nanosilvers (AgNPs) and black phosphorus (BP) using electrospinning technology. The water contact angle of PL-n decreased significantly from 144.00 ± 1.00° for PL-0 to 0° for PL-2. The photothermal temperature increased significantly from 27.27 ± 0.25 °C for PL-0 to 40.7 ± 0.15 °C for PL-2. After exposure to near-infrared ray (NIR), the release rate of PL-2 increased from 78.00 ± 2.95 % to 89.46 ± 2.05 %. Biological experiments demonstrated that NIR-assisted PL-2 has excellent antibacterial and biofilm ablation activity with good biocompatibility. Furthermore, in vivo studies indicated that the NIR-assisted PL-2 accelerated wound healing by stimulating granulation tissue formation, collagen deposition, and angiogenesis and decreasing expression levels of CD68. The study suggests that this bi-functional nanofiber is indeed a versatile wound dressing, and is expected to be applied in clinical settings.

Synthesis of Smart Nanofiber Coatings with Autonomous Self-Warning and Self-Healing Functions.

Organic protective coatings are widely used to protect metal structures from corrosion but they are vulnerable to undetectable damage. Without timely detection and repair, it could lead to severe consequences. How to warn and heal damaged areas simultaneously and automatically has become a challenging problem. Herein, we report an intelligent protective coating with self-warning and self-healing functions. This strategy was achieved by embedding bifunctional nanofibers containing 1,10-phenanthroline (Phen) in organic coatings. The nanofibers with Phen as a core and a poly(vinyl alcohol) (PVA)─chitosan (CS) blend solution as a shell were synthesized by coaxial electrospinning. The PVA/CS@Phen nanofiber-embedded coating displayed self-healing and high contrast indication function of the damaged area on coatings. Prominent red could warn microdamage and macrosurface damage, which occurred rapidly and healed permanently. The intelligent coating exhibited high healing performance under artificial injury with self-warning characteristics, and the cure rate was about 98.4% without external intervention. In the healing process, free amino groups of CS in the shell of nanofibers enhanced the sustained release of Phen. This convenient, economical, and efficient strategy with cooperative functions of self-warning and self-healing delivers an effective solution for prolonging the service life of protective coatings. This multifunctional coating exhibits excellent potential in the field of marine engineering applications.

Complex permittivity‐dependent plasma confinement‐assisted growth of asymmetric vertical graphene nanofiber membrane for high‐performance Li‐S full cells

AbstractVertical graphene (VG), possessing superior chemical, physical, and structural peculiarities, holds great promise as a building block for constructing a high‐energy density lithium‐sulfur (Li‐S) battery. Therefore, it is desirable to develop a new VG growth technique with a novel structure to enable wide applications. Herein, we devise a novel complex permittivity‐dependent plasma confinement‐assisted VG growth technique, via asymmetric growing a VG layer on one side of N‐doped carbon nanofibers for the first time, using a unique lab‐built high flux plasma‐enhanced chemical vapor deposition system, as a bifunctional nanofiber membrane to construct Li‐S batteries with low negative/positive (N/P) and electrolyte/sulfur (E/S) ratios. The unique nanofiber membrane could simultaneously protect the cathode and anode, enabling an excellent electrochemical performance with low N/P and E/S ratios in Li‐S batteries. Such a full cell delivers high gravimetric energy density and volumetric energy density of 340 Wh kg−1 and 547 Wh L−1, respectively, at low N/P (2:1) and E/S (4:1) ratios. Furthermore, a pouch cell achieves a high areal capacity of 7.1 mAh cm−2 at a sulfur loading of 6 mg cm−2. This work put forward a novel pathway for the design of high‐energy density Li‐S batteries.image

Eugenol-acacia gum-based bifunctional nanofibers as a potent antifungal transdermal substitute.

Aim: Fungal biofilms interfere with the wound healing processes. Henceforth, the study aims to fabricate a biomaterial-based nano-scaffold with the dual functionalities of wound healing and antibiofilm activity. Methods: Nanofibers comprising acacia gum, polyvinyl alcoholand inclusion complex of eugenol in β-cyclodextrin (EG-NF) were synthesized using electrospinning. Antibiofilm studies were performed on Candida species, and the wound-healing activity was evaluated through an in vivo excision wound rat model. Results: The EG-NF potentially eradicated the mature biofilm of Candida species and their clinical isolates. Further, EG-NF also enhanced the re-epithelization and speed of wound healing in in vivo rat experiments. Conclusion: The study established the bifunctional applications of eugenol nanofibers as a transdermal substitute with antifungal potency.

Trimetallic composite nanofibers for antibacterial and photocatalytic dye degradation of mixed dye water.

Membrane technology is an advanced approach to making a healthier and cleaner environment. Using such catalytic membrane technology to get clean, usable water by removal of dye impurities as well as pathogenic microbes is the main goal behind the research work. Here, we present the synthesis and efficacy study of polymethyl methacrylate (PMMA)-based Ag/ZnO/TiO2 trimetallic bifunctional nanofibers with antibacterial and photocatalytic activity. The nanofibers have been proven to be effective for the degradation of methylene blue (MB 93.4%), rhodamine B (Rh 34.6%), auramine-O (Au 65.0%) and fuchsin basic (FB 69.8%) dyes individually within 90 min in daylight. The study is further extended in abating a mixture of these dyes from contaminated water using composite nanofibers. Also, in the case of a mixture of these dyes (3 ppm each), nanofibers show dye degradation efficiency (DDE) of 90.9% (MB), 62.4% (Au) and 90.3% (FB and Rh) in 60 min. The role of Ag nanoparticles with a synergic photocatalytic effect on ZnO and TiO2 is also demonstrated. Also, PMMA/ZnO/TiO2 composite fiber membrane in synergy with silver particles shows better antibacterial activity against Gram-negative bacteria E. coli, making PMMA/Ag/ZnO/TiO2 fibers a promising candidate in water purification.Electronic supplementary materialThe online version of this article (10.1007/s13204-020-01540-6) contains supplementary material, which is available to authorized users.

Bifunctional CuS composite nanofibers via in situ electrospinning for outdoor rapid hemostasis and simultaneous ablating superbug

Outdoor sports or combat missions, such as jungle adventures or counter-piracy operations, often involve bleeding and infected wounds. Due to the poor and limited medical conditions in these outdoor situations, patients prefer an easy way to simultaneously treat blood loss and wound infection by using the same outdoor device and the same material. In this study, a portable electrospinning device (150 g in weight) for outdoor use was developed, and CuS composite nanofibers could be green-synthesized by this portable electrospinning device. These CuS composite nanofibers can be deposited in situ onto the wound to simultaneously achieve rapid hemostasis outdoors and ablate superbacteria without requiring the use of other materials or devices. These in situ electrospun nanofibers possess better compactness on the rough wound surface than conventional nanofiber mats pressed onto the wound site. Thus, the nanofiber not only accelerates the hemostasis (<6 s) but also shortens the healing time of the wound with superbacterial infection (18 days). These bifunctional nanofibers combined with a portable electrospinning device for outdoor rapid hemostasis and simultaneous superbug ablation could notably benefit the outdoor first aid.

Flexible self-supporting bifunctional [TiO2/C]//[Bi2WO6/C] carbon-based Janus nanofiber heterojunction photocatalysts for efficient hydrogen evolution and degradation of organic pollutant

A novel [TiO2/C]//[Bi2WO6/C] carbon-based Janus nanofiber heterojunction photocatalyst (denoted as JNHP) was designed and constructed via conjugate electrospinning combined with subsequent calcination process. The JNHP with unique Janus structure has two sides: one side is TiO2/C nanofiber which responds to ultraviolet light, the other side is Bi2WO6/C nanofiber responding to visible light, thus effectively utilizing sunlight. JNHP possesses excellent bi-functionality of photocatalytic hydrogen production and methylene blue (MB) degradation. Hydrogen production rates of JNHP reach respectively as high as 11.58 and 16.32 mmol h−1 g−1 under visible light and simulated sunlight irradiation, and no noble metal is needed to add as cocatalyst in the process of hydrogen production, and further the photo-degradation rates of MB respectively are 93.3% (160 min) and 97.9% (140 min). Compared with counterpart TiO2/C and Bi2WO6/C carbon-based nanofiber photocatalysts, enhanced photocatalytic performance of JNHP mainly results from the synergistic effect of unique heterojunctions between TiO2 and Bi2WO6 and one-dimensional conductive carbon nanofiber (CNFs). Furthermore, JNHP with one-dimensional flexible self-supporting structure can be easily separated from the solution and has excellent recyclable stability. The proposed designing philosophy and preparation approach have guiding significance for the development of other one-dimensional bifunctional nanofiber photocatalysts.

A novel strategy of fabricating GdOF:Er3+ nanofibers possessing upconversion luminescence and paramagnetic properties: The combination of electrospinning with fluoro-oxidation technique

Upconversion luminescent-magnetic bifunctional GdOF:Er3+ nanofibers have been successfully acquired by means of the combination of electrospinning and fluoro-oxidation calcination technique for the first time. The products have been certified to be pure rhombohedral phase GdOF on the basis of the structural analysis via X-ray powder diffraction (XRD). Scanning electron microscope (SEM) image shows the morphology of GdOF:Er3+ samples is fibrous and the mean diameter is 88 ± 2 nm. Upconversion emission spectrum analysis manifests that GdOF:Er3+ nanofibers emit green and red upconversion emission centering at 523, 543 and 654 nm, respectively ascribed to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, 4F9/2 → 4I15/2 energy-level transitions of Er3+ ions under 980-nm ultrared laser excitation. The molar concentration of Er3+ has a great influence on upconversion luminescent intensity. When the doping concentration of Er3+ is 9%, upconversion luminescent intensity reaches to the maximum. Besides, the emission colors of the products are situated at the green region of the CIE chromaticity coordinates. Moreover, GdOF:Er3+ nanofibers demonstrate paramagnetic properties. More importantly, the upconversion luminescence and paramagnetic properties are simultaneously realized in single-phase GdOF:Er3+ nanofibers through our novel strategy, and the bifunctional nanofiber will possess wide applications. The formation mechanism of GdOF:Er3+ nanofibers is also proposed, which may provide some new guidance to manufacture other rare-earth oxyfiuoride upconversion luminescent-magnetic nanostructures with various morphologies.

Simultaneously enhanced photocatalytic and antibacterial activities of TiO2/Ag composite nanofibers for wastewater purification

High throughput of polyacylonitile (PAN)-based Ag/TiO2 composite nanofibers were prepared by using needleless electrospinning method. The morphology and crystallinity characterization revealed uniform and smooth nanofibers with an average diameter ranged from 160 to 260 nm. The enhanced photocatalytic activity of PAN/Ag/TiO2 compared with PAN/TiO2 nanofibers under visible light irradiation was linked with high interfacial charge transfer and low bandgap due to Ag entity. High photodegradation efficiency for methyl orange, rhodamine B and methylene blue were achieved as 99.5%, 92% and 99% respectively during the 4 h experiment. Effect of key parameters (i.e. pH, oxygen and Ag/TiO2 loading dosage) on photodegradation efficiency of dyes were also investigated. Active species trapping experiments demonstrated that O2− and OH were dominant active species in the photocatalytic degradation of dyes. These composite nanofibers have also exhibited excellent antibacterial activity, e.g. 95% of E. coli and 99% of S. aureus were killed in 2 h. Bifunctional nanofibers can be easily recovered from the aqueous solution as compared with the TiO2 nanoparticles. Moreover, the daily production rate of nanofibers has reached over 1.4 kg in the laboratory test, which is 60 times higher than that using the single needle electrospinning method. This production rate may be further optimized in the pilot scale studies. High productivity and strong catalytic properties of nanofibers propose their potential applications in environmental remediation for economically and eco-friendly wastewater and air treatment materials.

Basement Membrane Mimics of Biofunctionalized Nanofibers for a Bipolar-Cultured Human Primary Alveolar-Capillary Barrier Model.

In vitro reconstruction of an alveolar barrier for modeling normal lung functions and pathological events serve as reproducible, high-throughput pharmaceutical platforms for drug discovery, diagnosis, and regenerative medicine. Despite much effort, the reconstruction of organ-level alveolar barrier functions has failed due to the lack of structural similarity to the natural basement membrane, functionalization with specific ligands for alveolar cell function, the use of primary cells and biodegradability. Here we report a bipolar cultured alveolar-capillary barrier model of human primary cells supported by a basement membrane mimics of fully synthetic bifunctional nanofibers. One-step electrospinning process using a bioresorbable polyester and multifunctional star-shaped polyethylene glycols (sPEG) enables the fabrication of an ultrathin nanofiber mesh with interconnected pores. The nanofiber mesh possessed mechanical stability against cyclic expansion as seen in the lung in vivo. The sPEGs as an additive provide biofunctionality to fibers through the conjugation of peptide to the nanofibers and hydrophilization to prevent unspecific protein adsorption. Biofunctionalized nanofiber meshes facilitated bipolar cultivation of endothelial and epithelial cells with fundamental alveolar functionality and showed higher permeability for molecules compared to microporous films. This nanofiber mesh for a bipolar cultured barrier have the potential to promote growth of an organ-level barrier model for modeling pathological conditions and evaluating drug efficacy, environmental pollutants, and nanotoxicology.

Electrospun Fe3O4/PVP//Tb(BA)3phen/PVP magnetic–photoluminescent bifunctional bistrand aligned composite nanofibers bundles

Fe3O4/PVP//Tb(BA)3phen/PVP magnetic–photoluminescent bifunctional bistrand aligned composite nanofibers bundles based on Fe3O4 nanoparticles (NPs) and terbium complex Tb(BA)3phen (BA = benzoic acid) were fabricated by employing a parallel axial electrospinning setup and were characterized by X-ray diffraction, field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), transmission electron microscopy, fluorescence spectroscopy, and vibrating sample magnetometer. It is found that Fe3O4 NPs were only dispersed into one strand of the bistrand aligned composite nanofibers bundles, but no nanoparticles in the other strand. And the average diameter of the individual strand fiber was 200 ± 25 nm. The bistrand aligned composite nanofibers bundles exhibit strong green emissions under the excitation of 275 nm ultraviolet light, and the 5D4 → 7F5 hypersensitive transition at 545 nm was the predominant emission peak of Tb3+ ions. The newly obtained bifunctional nanofibers bundles exhibit excellent magnetism and high fluorescence intensity and are expected to apply in biology cell separation, magnetic resonance imaging, drug deliver, and fluorescence immunoassays/imaging.

Electrospun novel bifunctional magnetic–photoluminescent nanofibers based on Fe 2O 3 nanoparticles and europium complex

Novel bifunctional magnetic–photoluminescent nanofibers based on Fe 2O 3 nanoparticles and europium complex Eu(DBM) 3(Bath) (DBM = dibenzoylmethanate, Bath = bathophenanthroline) have been prepared by electrospinning. Extensive characterizations of the resulting bifunctional nanofibers have been performed using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The influence on photoluminescence properties of bifunctional nanofibers of the addition of Fe 2O 3 nanoparticles has also been studied. The results indicate that due to decreased symmetry in the composite nanofibers the excitation bands of the composite nanofibers are split into two different components. Furthermore, the existence of the Fe 2O 3 and polymer hybrid matrixes can improve the thermal and photo stability of the europium complex and elongate the fluorescence lifetime of the europium complex.