Organic Nanofibers Research Articles

Rational designing of tree-like polymer gel membrane based on PVDF/lamellar organic montmorillonite nanofiber with excellent flame retardancy and superior ion conductivity for high-performance lithium-ion capacitor

A tree-like structured gel nanofibrous membrane (TLNM) including lamellar organic montmorillonite (OMMT) is designed and prepared via one-step electrospinning method. And its application as promising separator for lithium-ion capacitor were systematically researched. Based on the special structure and the addition of lamellar OMMT, the TLNMs are endowed improved mechanical performance, excellent thermal stability and flame-retardant, and good electrochemical properties for Li ion capacitor (LIC). As a result, the nanofibrous membranes exhibits enhanced electrolyte uptake performance (~870%, with an electrolyte contact angel of 0°) and robust thermal dimensional stability (stable at 160°C for 1.5 h). Furthermore, the limiting oxygen index of this membrane is as high as ~30%, which can significatively improve the safety of the nanofiber separator. And the assembled Li ion capacitor with the membrane presented superior ion conductivity (3.95*10−3 S cm−1). Additionally, the LIC also shows enhanced cycling stability (~60% capacity retention after 10,000 cycles at 0.5C), and favorable rate capability. All of the results indicate that the novel polymer gel membrane including excellent flame retardancy and superior ion conductivity is expected to be used for high-performance lithium-ion capacitor.

Templating Synthesis of Metal–Organic Framework Nanofiber Aerogels and Their Derived Hollow Porous Carbon Nanofibers for Energy Storage and Conversion

A kind of metal-organic framework (MOF) aerogels are synthesized by the self-assembly of uniform and monodisperse MOF nanofibers. Such MOF nanofiber aerogels as carbon precursors can effectively avoid the aggregation of nanofibers during calcination, resulting in the formation of well-dispersed hollow porous carbon nanofibers (HPCNs). Moreover, HPCNs with well-dispersion are investigated as sulfur host materials for Li-S batteries and electrocatalysts for cathode oxygen reduction reaction (ORR). On the one hand, HPCNs act as hosts for the encapsulation of sulfur into their hierarchical micro- and mesopores as well as hollow nanostructures. The obtained sulfur cathode exhibits excellent electrochemical features, good cycling stability and high coulombic efficiency. On the other hand, HPCNs exhibit better electrocatalytic activity than aggregated counterparts for ORR. Furthermore, a highly active single atom electrocatalyst can be prepared by the carbonization of bimetallic MOF nanofiber aerogels. The results indicate that well-dispersed HPCNs show enhanced electrochemical properties in contrast to their aggregated counterparts, suggesting that the dispersion situation of nanomaterials significantly influence their final performance. The present concept of employing MOF nanofiber aerogels as precursors will provide a new strategy to the design of MOF-derived nanomaterials with well-dispersion for their applications in energy storage and conversion.

Fabrication of photoluminescent electrospun poly(styrene-co-methyl methacrylate) nanofibers integrated with LaPO4:Eu3+ for optical applications

Organic luminescent nanofibers owing to their flexibility and anisotropic emission along the axis when compared to direction perpendicular to axis are gaining much importance as luminescent probes and in a variety of other optic applications. Of the different organic luminescent nanofibers the one which is of recent interest is the rare earth integrated electrospun polymeric nanofibers. Among different host matrices the most suitable one is polymer in view of electrospinning technique as it facilitates the spinnability of the solution which is a matter of concern when coming to electrospinning technique and also enhances the flexibility of the product. Rare earths are the most apt material of choice when the research focus into luminescent applications. Among a number of rare earths of choice the one with greater potential is undoubtedly europium ion because of its intense emission in the orange red region on UV excitation. In the present study the polymer chosen is poly (styrene-co-methyl methacrylate) which is a copolymer of polystyrene and polymethyl methacrylate and the rare earth integrated is LaPO4:Eu3+. The surface morphologyanalysis and optical characterizations are done by SEM, EDX, XRD, PL and IR techniques. The sem analysis shows that the average fiber diameter distribution increased from the range of 70 nm to 120 nm on integration of LaPO4:Eu3+. The shift of maximum excitation wavelength in the UV spectra and presence of characteristic bands of Eu3+ ions in the region 579 to 610 nm in the integrated nanofibers shows that the rare earth is very well distributed into the polymer matrix. Also there is significant enhancement in the intensity of integrated nanofiber.

Determination of ciprofloxacin drug with molecularly imprinted polymer/co- metal organic framework nanofiber on modified glassy carbon electrode (GCE)

In this paper, we report the Co-metal organic frameworks (MOFs) were successfully synthesized with the aid of 2,6-pyridinedicarboxylic acid ammonium as an organic ligand in polylactic acid (PLA) as a biodegradable and biocompatibility polymer substrate through the ultrasonic-assisted electrospinning method. Co-MOFs/PLA nanofiber used as a new nanocomposite for design and construction of nanosensor based on the polymer prepared of the 4-aminobenzoic acid electrolytic molecule for measuring ciprofloxacin (CIP) drug class. The molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) sensors were studied by differential pulse voltammetry (DPV) to study changes in oxidation peaks and reduction of potassium ferricyanide. The calibration curve for ciprofloxacin was in the range of 0.5–150 μM also the detection limit was 0.017 μM and the standard deviation for five consecutive measurements at 60 μM concentration was calculated1.7% respectively. For characterizing the synthesized Co-MOF/PLA nanofiber we used X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDAX), Transmission electron microscopy (TEM) and Dynamic light scattering (DLS). In this study, we present new nanosensors with Co-MOF/PLA nanofiber as a biodegradable and bioactive composite for the first time in modified carbon paste electrode using the ultrasound-assisted direct micelle (UADM) method as the determination of ciprofloxacin drug.

Non-invasive detection of silicosis based on array sensing and pattern recognition

Silicosis is a fibrotic lung disease caused by inhalation of silica dusts, early and accurate diagnosis of which remains a challenge. We aimed to assess the performance of a nanofiber sensor array and pattern recognition to promptly and noninvasively detect silicosis. A total of 210 silicosis cases and 430 non-silicosis controls were enrolled in a cross-sectional study. Exhaled breath was analysed by a portable analytical system incorporating an array of 16x organic nanofiber sensors. Models were established by Deep Neural Network and eXtreme Gradient Boosting. Linear Discriminant Analysis was used for dimensionality reduction and visualized data analysis. Receiver Operating Characteristic Curve, accuracy, sensitivity and specificity were used to evaluate models. Results: 99.3% AUC, 96.0% accuracy, 94.1% sensitivity, and 96.3% specificity were achieved in test set. Silicosis cases present different breath patterns from healthy controls, classification results using which were highly consistent with the experts’ diagnosis. Breath analysis performed with the sensor array and pattern recognition is expected to provide a quick, stable recognition for silicosis. In this paper, different forms of features, different algorithms and data sets over long time periods were used, which provides a reference for silicosis expiratory diagnosis scheme.

A lithiated organic nanofiber-reinforced composite polymer electrolyte enabling Li-ion conduction highways for solid-state lithium metal batteries

A robust composite polymer electrolyte is prepared by thermal lamination of PEO electrolyte films onto lithiated organic nanofibers, combining the merits of 3D Li-ion conduction highways and good nanofiber-reinforced mechanical properties.

Controllable self-patterning behaviours of flexible self-assembling peptide nanofibers.

In recent years, fabricating flexible one-dimensional nanofibers with a high aspect ratio and controlling their two-dimensional patterns on a certain surface have attracted more and more attention. Although molecular self-assembly as a useful strategy has been widely used to obtain nanofibers from soft materials such as peptides and polymers, extremely long nanofibers with high flexibility were rarely reported, and it's even more challenging to organize these organic nanofibers into ordered patterns in a controllable manner. In this study, we designed a flat-wedge-shaped bolaamphiphilic peptide which could self-assemble into ultra-flexible long nanofibers. These nanofibers were deposited on a mica surface by long-term incubation and exhibited various self-patterning behaviours as controlled by intended treatment. By changing the incubation time on the mica surface, vapour pH in the incubation device, and the peptide concentration, various patterns including nanofiber coils, parallel or single straight long nanofibers, and a network of hexagonally aligned short nanofibers could be obtained. These results indicated that not only the nanostructure formed by self-assembling peptides, but also the higher-order patterning behaviour of the nanostructures could be rationally controlled, providing a promising strategy for fabricating complicated nanoscale architectures with various potential applications.

Fabrication of One-Dimensional Organic Nanofiber Networks via Electrophoretic Deposition for a Nonvolatile Memory Device.

Despite many advanced growth methodologies for organic nanofibers (ONFs), the lack of efficient and scalable ONF-based film preparation technologies has long been a hindrance in their practical application in organic electronic devices. Here, a typical cathode electrophoretic deposition (C-EPD) technology was developed to controllably produce ONFs and their corresponding thin films. Using the solvent effect and an external electric field force during the C-EPD process, a one-dimensional ONF network was formed, which exhibits compact molecular packing and superior optoelectronic properties in the thin-film state. Prototype sandwich-structure memory devices based on these ONF films exhibited a binary nonvolatile memory performance significantly superior than that of the bulk materials. This study provides an efficient and scalable ONF fabrication technology for high-performance electronic devices in various potential applications.

Preparation of a Novel Ti-metal Organic Framework Porous Nanofiber Polymer as an Efficient Dental Nano-coating: Physicochemical and Mechanical Properties

ABSTRACT In this work, Ti-metal-organic framework nonofiber (MOFNF) was prepared using electrospinning method and its thermodynamic, morphological and mechanical properties was considered using related analyses, based on the ideal features of MOF and NFs using fractional factorial design. While preparing nano-coatings with some capabilities such as environmental friendly, transparent, desirable mechanical and physicochemical properties are significant, the MOFNF was used as nano-coatings with surface area close to 3204 m2/g, thermal stability upto 368°C and 559 Pa compressive strength in dentistry. This study could be a new strategy for making dental nano-coatings with desired properties.

Physical and supercapacitive behavior of inorganic–organic hybrid carbon nanofibers derived from silole

Silole-derived porous carbon nanofibers (Si-CNFs) with oxygen-containing functional groups are prepared by electrospinning using silole as an inorganic precursor to improve the electrode performance. Since silole is easily decomposed and causes high oxygen diffusion rates, it produces well-developed pores and more heteroatoms through spontaneous sol–gel processing of silole in the subsequent stabilization process. The presence of more polar oxygen functional groups on the surface leads to denser adsorption of the electrolyte ions on the surface, thereby improving the electrochemical capacity. The resulting Si-CNF composites deliver a high specific capacitance of 180 Fg−1 and energy density of 23.0 Whkg−1 in an aqueous electrolyte.

Electrospinning Growth Parameters Dependent PVP: PC71BM Nanofiber Structure Characterizations and Modeling

As green materials, the organic nano-fiber membranes are very potential for diverse functional purposes. The growth parameters based fiber alignment; surface morphology and diameter are key attentions to control mechanical, structural, electrical, and optical properties. These physical aspects of nanofiber are diversified its practical significance in which control of growth techniques is vital. Electrospinning is a facile but pragmatic approach to adjust the growth process by regulating growth parameters. In this study, fabrication of spinning parameter preference to control the nanofiber shape, diameters, and crystalline property are investigated. Different % weight of PVP and PC71BM mixture solution for electrospinning are used in this study. It is observed that the average applied field and solution concentration of active materials are paramount to well-aligned uniform diameter nanofiber having better structure and crystalline properties. The scanning electron microscopic (SEM) study of nanofiber micrograph shows the diameter size of nanofiber and it is validated by Response Surface Model (RSM). A sharp peak of polymer fiber is shown by X-ray diffraction (XRD) that realizes worthy nano-crystalline property. The overall growth process is reinforced by validation from RSM analysis.

Redox active covalent organic framework-based conductive nanofibers for flexible energy storage device

Covalent organic frameworks (COFs) constitute a family of crystalline porous polymers that are being studied for electrochemical energy storage. However, their low electrical conductivity and poor processability have largely limited their electrochemical performances and practical applications. Here, we develop an interfacial synthesis method to grow few-layered 2D redox-active COFs (DAAQ-TFP COF) on the surface of carboxylated carbon nanotubes (c-CNTs) in order to fabricate core-shell c-CNT@COF nanofibers, for which the thickness and the morphology of the COF nanolayers can be finely controlled. When using the c-CNT@COFs as electrode material, the tailored nanostructure with high electrical conductivity allows efficient electron transfer, while the few-layered structure of the COF promotes fast electrolyte ion diffusion in the near-surface region, which results in an efficient utilization of the redox active sites in COF. More significantly, c-CNT@COFs with nanofibrous structure show good processability and can be assembled into freestanding and flexible nanopapers with the assistance of Cladophora cellulose. Given the good electrochemical performance and excellent flexibility, the nanopaper electrodes are assembled into flexible hybrid capacitors, showing high areal capacitance and extremely long lifetime. This study provides a new pathway for the development of next generation sustainable and flexible energy storage devices based on COFs and cellulose materials.

Smart formaldehyde detection enabled by metal organic framework-derived doped electrospun hollow nanofibers

In this work, the metal-organic framework (MOF)-derived Zn2+ doped SnO2 (ZZS) hollow nanofibers (HNFs) have been successfully synthesized via facile electrospinning and annealing techniques for achieving the low concentration of HCHO monitoring. As the hollow nanostructure and the optimized Zn2+ homogeneous doping behavior ensure all the smooth electrons transfer, abundant chemisorbed active sites and oxygen vacancies, the 15 wt% ZZS HNFs exhibited the excellent gas-sensing property with a sensing response value of 25.7 towards 100 ppm HCHO, fast response/recovery time (12 /45 s) and the detection capacity of HCHO down to 500 ppb in a rapid response/recovery time (10 /2 s) compared with pristine SnO2 and other ZZS HNFs. Moreover, when assembled into a practical smart detection device for real-time monitoring and early warning of HCHO, the 15 wt% ZZS HNFs still presented high sensitivity of HCHO, highlighting its bright commercial prospect in the future of smart indoor air quality monitoring.

Synthesis of PLGA/chitosan/zeolites and PLGA/chitosan/metal organic frameworks nanofibers for targeted delivery of Paclitaxel toward prostate cancer cells death

In the present study, the various zeolites including hydrophilic Y zeolite, hydrophobic ZSM-5 zeolite and metal organic frameworks (MOFs) including MIL-101 and ZIF-8 were incorporated into the PLGA/chitosan nanofibers for controlled release of Paclitaxel anticancer drug against prostate cancer in vitro and in vivo. The synthesized nanoparticles and nanofibers were characterized using FTIR, XRD, SEM, BET and water contact angle analysis. The drug loading efficiency of nanofibers containing zeolites and MOFs indicated that the MOFs were more useful compared with zeolites for higher loading of Paclitaxel molecules. The Paclitaxel release behavior from nanofibers containing zeolites and MOFs were also examined. The MTT assay and DAPI staining analysis were used to determine the cytotoxicity and apoptosis effect of nanofibers containing Paclitaxel against LNCaP prostate cancer cell lines. The tumor inhibition rate in vivo was carried out to obtain the optimum nanofibrous formulation with maximum cell death percentage and tumor inhibition rate. The obtained results revealed the better activity of MOFs compared nanozeolites for higher loading of Paclitaxel drug into the nanoparticles and a more sustained release of drug from nanofibers containing MOFs.

Fabrication of poly(acrylic acid) grafted-chitosan/polyurethane/magnetic MIL-53 metal organic framework composite core-shell nanofibers for co-delivery of temozolomide and paclitaxel against glioblastoma cancer cells.

In the present study, the magnetic MIL-53 nanometal organic framework particles (NMOFs) were incorporated into poly(acrylic acid) grafted-chitosan/polyurethane (PA-g-CS/PU) core-shell nanofibers for controlled release of temozolomide (TMZ) and paclitaxel (PTX) against U-87 MG glioblastoma cells during chemotherapy/hyperthermia combined method. The synthesized magnetic MIL-53 NMOFs and NMOF-loaded nanofibers were characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transformed infrared (FTIR), vibrating-sample magnetometer (VSM) and scanning electron microscopy (SEM) analysis. The TMZ and PTX release profiles from magnetic MIL-53 5wt% loaded-CS-g-PAA-PTX-TMZ/PU fibers were investigated under acidic and physiological pH at temperatures of 37 and 43°C. The effect of hyperthermia on the release rate of TMZ and PTX from magnetic nanofibers was investigated. An alternating magnetic field could induce the mild hyperthermia (43°C) for the cells treated with magnetic MIL-53 5wt% loaded-CS-g-PAA-PTX-TMZ/PU fibers during 10min. The release data were best described by the non-Fickian diffusion of Korsmeyer-Peppas equation. The cell viability, flowcytometry and Bcl-2, Bax expression levels were investigated to obtain the optimum nanofibrous carrier for apoptosis of U-87 MG cells in vitro. The obtained results indicated that the synthesized magnetic MIL-53 NMOFs loaded- PA-g-CS/PU/TMZ-PTX nanofibers (shell flow rate: 0.8 mLh-1) could be used as a targeted delivery of anticancer agents with maximum apoptosis of 49.6% of U-87 MG glioblastoma cells under AMF during chemotherapy/hyperthermia combination therapy.

Biomimetic sensor for ethambutol employing β-cyclodextrin mediated chiral copper metal organic framework and carbon nanofibers modified glassy carbon electrode

Stereochemical configuration of the drug is responsible for racemic switch with enantiomers in presence of chiral environment for human beings. Therefore, its determination in racemic and pharmaceutical samples becomes a challenge. Addressing this issue, an enantioselective electrochemical biomimetic sensor for discrimination of isomers of ethambutol (ETB) employing square wave voltammetry (SWV) is reported for the first time. For this purpose, a chiral host, β-Cyclodextrin based copper metal organic framework (CD-CuMOF) was synthesized and used for chelate complexation of ETB isomers (SS-ETB/RR-ETB). A glassy carbon electrode (GCE) is chemically modified using CD-CuMOF and carbon nanofibers (CNF) composite material to construct a sensor in the form of (CD-CuMOF-CNF-GCE). The behaviour of CD-CuMOF for ETB isomers on GCE is postulated to be an artificial enzyme model (AEM) as it mimics the catalytic activity similar to enzyme alcohol dehydrogenase for ETB. The biosensor exhibits excellent peak potential difference (ΔEp (SS-RR) = 108 mV) between ETB isomers using SWV showing a clear distinction in the racemic mixture. It showed a linear response in the range of 1.0 x 10-7 to 1 x 10-4 M and 5.0 x 10-7 to 2.5 x 10-4 M with low detection limit of 3.10 x 10-8 M and 8.52 x 10-8 M for RR-ETB and SS-ETB isomers respectively. The sensor was applied for the estimation of ETB isomers in racemic mixture and real samples viz., blood, urine and pharmaceutical. The CD-CuMOF is a low-cost material with higher stability than enzyme and offers an advantage for sensing and catalysis in future.

Electrospinning fabrication of covalent organic framework composite nanofibers for pipette tip solid phase extraction of tetracycline antibiotics in grass carp and duck

In the current study, a novel covalent organic frameworks COF-SCU1 incorporated electrospun nanofibers (PAN@COF-SCU1 nanofibers) was fabricated via a facile electrospinning method and utilized as adsorbent in pipette tip solid-phase extraction (PT-SPE) of tetracycline antibiotics (TCs) from foods. The prepared PAN@COF-SCU1 nanofibers possessed both of the unique characteristics of electrospun nanofibers and COFS-CU1, and thus improving the adsorption capacity of the electrospun nanofibers and preventing the problems of leakage and high pressure caused by directly using the nanosize COFs as adsorbent in PT-SPE. The experiments affected the adsorption and desorption efficiencies, such as the loading ratios of COFS-CU1 in nanofibers, the amount of nanofibers, the matrix pH and desorption solvent, were studied in detail. Eventually, a new pipette tip solid-phase extraction-high performance liquid chromatography (PT-SPE/HPLC) method was proposed for the analysis of three TCs from food. Satisfied linearity for TCs was obtained in the range of 4–70 ng mL−1. The limits of detection and quantification were ranged from 0.6 to 3 ng mL−1 and from 2 to 10 ng mL−1, respectively. The interday and intraday precisions (RSD) were all lower than 9%. The proposed PT-SPE/HPLC method was used to determine TCs residues in grass carp and duck samples for the first time. The results could not only explore the availability of PT-SPE in the extraction of TCs in food samples, but also broadened the potential applications of COFs in sample preparation.

Electrospun nanofiber-based cancer sensors: A review.

Cancer is a malignancy engendering enormous global mortality, steering extensive research for early diagnosis and efficacious prognosis leading to emergence of cancer sensing technologies for multitudinous biomarkers. In this context, nanofibers, imparting high surface area, facile production, morphology control, and synergistic properties attainable, are poised to be inevitable in futuristic sensing devices for predictive diagnostics when integrated with artificial intelligence and machine learning. To this end, fundamentals governing the sensor response and their analytical performance have been discussed. The headways in organic and inorganic nanofibers for biomarker gas sensing, fluid sample sensing and imaging have been supplemented with discussions on materials for nanofiber formation, along with sensitizing materials, and formation of sensing elements by processes like surface deposition on nanofibers, immobilising, calcination, etc. and their effect on final sensing device properties. The review culminates by summarising the conceptual understanding of the hitherto progress leading to achievement of excellent analytical performance giving detection limits to the order of 1.6pM concentration and response time of as low as 0.5s. Current bottlenecks in this state of the art have been delineated and pathways for future research are discussed.

A Review on Electrospun Luminescent Nanofibers: Photoluminescence Characteristics and Potential Applications

<P>Background: Photoluminescent materials have been used for diverse applications in the fields of science and engineering, such as optical storage, biological labeling, noninvasive imaging, solid-state lasers, light-emitting diodes, theranostics/theragnostics, up-conversion lasers, solar cells, spectrum modifiers, photodynamic therapy remote controllers, optical waveguide amplifiers and temperature sensors. Nanosized luminescent materials could be ideal candidates in these applications. </P><P> Objective: This review is to present a brief overview of photoluminescent nanofibers obtained through electrospinning and their emission characteristics. </P><P> Methods: To prepare bulk-scale nanosized materials efficiently and cost-effectively, electrospinning is a widely used technique. By the electrospinning method, a sufficiently high direct-current voltage is applied to a polymer solution or melt; and at a certain critical point when the electrostatic force overcomes the surface tension, the droplet is stretched to form nanofibers. Polymer solutions or melts with a high degree of molecular cohesion due to intermolecular interactions are the feedstock. Subsequent calcination in air or specific gas may be required to remove the organic elements to obtain the desired composition. </P><P> Results: The luminescent nanofibers are classified based on the composition, structure, and synthesis material. The photoluminescent emission characteristics of the nanofibers reveal intriguing features such as polarized emission, energy transfer, fluorescent quenching, and sensing. An overview of the process, controlling parameters and techniques associated with electrospinning of organic, inorganic and composite nanofibers are discussed in detail. The scope and potential applications of these luminescent fibers also conversed. </P><P> Conclusion: The electrospinning process is a matured technique to produce nanofibers on a large scale. Organic nanofibers have exhibited superior fluorescent emissions for waveguides, LEDs and lasing devices, and inorganic nanofibers for high-end sensors, scintillators, and catalysts. Multifunctionalities can be achieved for photovoltaics, sensing, drug delivery, magnetism, catalysis, and so on. The potential of these nanofibers can be extended but not limited to smart clothing, tissue engineering, energy harvesting, energy storage, communication, safe data storage, etc. and it is anticipated that in the near future, luminescent nanofibers will find many more applications in diverse scientific disciplines.</P>

Multifarious Chiral Nanoarchitectures Serving as Handed-Selective Fluorescence Filters for Generating Full-Color Circularly Polarized Luminescence.

A series of full-color circularly polarized luminescence (CPL)-active materials are fabricated by judiciously combining multifarious chiral nanoarchitectures with achiral fluorescence dyes. The investigated nanoarchitectures include organic polymer nanofibers, organic-inorganic hybrid nanoflowers, and inorganic nanoflowers. The as-prepared chiral nanoarchitectures all can act as handed-selective fluorescence filters to powerfully transform unpolarized fluorescent light into circularly polarized luminescence. Also notable, no interaction is required between chiral and fluorescent components for achieving CPL emission. The present study provides a convenient and universal approach for preparing full-color CPL materials. Following the strategy, numerous chiroptical materials with CPL performance can be expected due to the abundant chiral matters and achiral fluorophores.