Organic Nanofibers Research Articles

Metal–organic framework-induced mesoporous carbon nanofibers as an ultrastable Na metal anode host

Etch-free MOF-induced broad-range mesoporous CNFs are prepared by electrospinning, enabling a highly stable Na metal anode.

Constructing Amino-Functionalized Flower-like Metal-Organic Framework Nanofibers in Sulfonated Poly(ether sulfone) Proton Exchange Membrane for Simultaneously Enhancing Interface Compatibility and Proton Conduction.

A novel flower-like MIL-53(Al)-NH2 nanofiber (MNF) was successfully constructed, in which the electro-blown spinning Al2O3 nanofibers were introduced as Al precursors to coordinate with ligand in hydrothermal reaction for the formation of MOFs nanofibers. By incorporating the functional and consecutive MNFs fillers in sulfonated poly(ether sulfone) (SPES) matrix, high-performance MNFs@SPES hybrid membranes were obtained. Specifically, the peak stress strength could be strengthened to 33.42 MPa and the proton conductivity was remarkably improved to 0.201 S cm-1 as MNFs content increased to 5 wt %, achieving a simultaneous improvement on proton conduction and membrane stability. The highly promoted performance could be ascribed to the synergy advantages of unique structure and amino modification of MNFs: (1) The flower-like nanofiber structure of MNFs with high surface area could be beneficial to construct long-range and compatible interfaces between MNFs and SPES matrix, leading to sufficient continuous proton pathways as well as strengthened stability for the hybrid membrane. (2) The hydrophilic MNFs rendered the hybrid membrane with sufficient water retention for proton transfer via Vehicle mechanism. (3) Functional -NH2 groups of MNFs and -SO3H groups of SPES were consecutively and tightly bonded via acid-base electrostatic interactions, which further accelerated the proton conduction via Grotthuss hopping mechanism and effectively suppressed the methanol penetration in the meanwhile for the MNFs@SPES hybrid membranes.

Magnetic and Electric Control of Circularly Polarized Emission through Tuning Chirality-Generated Orbital Angular Momentum in Organic Helical Polymeric Nanofibers.

Circularly polarized light emission promotes the development of smart photonic materials for advanced applications in chiral sensing and information storage. The orbital angular momentum is a unique property for organic chiral helical materials. In this work, a type of organic chiral polymeric nanowires is designed with strong chirality induced orbital angular momentum. Under the stimulus of an external magnetic field of 600 mT, circularly polarized emission from the chiral polymeric nanowire becomes more pronounced, where the g factor increases from 0.21 to 0.3. The observed phenomena mainly originate from the chirality-dependent orbital angular momentum. Moreover, the orbital angular momentum in helical chiral nanowire structures can be suppressed by inhibiting electron transport in a helical way to diminish circularly polarized light emission at room temperature.

Aggregation-Induced Energy Transfer in Color-Tunable Multiblock Bottlebrush Nanofibers.

The synthesis of multicomponent nanoscale structures with precisely addressable function is critical to the discovery of both new phenomena and new applications in nanotechnology. Though self-assembly offers low-cost routes to many such materials, these methods often require building blocks with particular structural motifs, thus limiting the scope of nanomaterials that can be prepared in these ways. Herein we use a bottom-up approach based on covalent chemistry to synthesize a series of bottlebrush copolymers from red, green, and blue luminescent macromonomers, which were then used to prepare multiblock organic nanofibers structurally analogous to nanoscale RGB pixels. Efficient energy transfer from a blue fluorophore to red and green phosphors can be modulated, using the solvent polarity as a stimulus, to give aggregation-induced changes in emission color. Aggregation was also accompanied by changes in the emission lifetime of the nanofiber from the nanosecond to microsecond regime. Additionally, changes in energy transfer efficiency and interchromophore distance were quantified using a FRET model. Preliminary demonstration of these materials as polarity-sensitive inks for encryption and encoding were also demonstrated using a red/blue fluorescence switch upon exposure to solvent. Finally, the potential complexity of optoelectronic materials accessible with these methods was demonstrated by combining these building blocks with charge-transporting materials to give organic nanofibers with ordered structures mimicking that of multilayer white OLEDs. Ultimately this work describes the preparation of robust, multicomponent nanofibers from general building blocks, combining their optoelectronic properties in ways that can be both reversibly switched and temporally resolved.

Core/Shell Piezoelectric Nanofibers with Spatial Self-Orientated β-Phase Nanocrystals for Real-Time Micropressure Monitoring of Cardiovascular Walls.

Implantable pressure biosensors show great potential for assessment and diagnostics of pressure-related diseases. Here, we present a structural design strategy to fabricate core/shell polyvinylidene difluoride (PVDF)/hydroxylamine hydrochloride (HHE) organic piezoelectric nanofibers (OPNs) with well-controlled and self-orientated nanocrystals in the spatial uniaxial orientation (SUO) of β-phase-rich fibers, which significantly enhance piezoelectric performance, fatigue resistance, stability, and biocompatibility. Then PVDF/HHE OPNs soft sensors are developed and used to monitor subtle pressure changes in vivo. Upon implanting into pig, PVDF/HHE OPNs sensors demonstrate their ultrahigh detecting sensitivity and accuracy to capture micropressure changes at the outside of cardiovascular walls, and output piezoelectric signals can real-time and synchronously reflect and distinguish changes of cardiovascular elasticity and occurrence of atrioventricular heart-block and formation of thrombus. Such biological information can provide a diagnostic basis for early assessment and diagnosis of thrombosis and atherosclerosis, especially for postoperative recrudescence of thrombus deep within the human body.

Self‐assembled core‐shell structured organic nanofibers fabricated by single‐nozzle electrospinning for highly sensitive ammonia sensors

AbstractElectrospinning is a unique method to prepare 1‐dimentional nanofiber for large‐scale manufacturing. Here in, we demonstrated chemical sensors based on the semiconducting nanofibers with core‐shell structure by simple single‐nozzle electrospinning with the spontaneous phase separation. The core‐shell structure nanofiber has large active sites which make it highly sensitive to chemical analytes. The thickness of the sensing shell can be tuned by controlling the mass ratio of core and shell components. As a demonstration, the nanofiber‐based sensor exhibits high sensitivity to low‐concentration ammonia (ppb level), as well as stability and reversibility. This unique fast single‐nozzle electrospinning technique used to fabricate semiconducting nanofibers with core‐shell structure provides a facile and designable process for the integration of multifunctional organic semiconducting layer into the organic electronic system.

Simultaneous green synthesis and in-situ impregnation of silver nanoparticles into organic nanofibers by Lythrum salicaria extract: Morphological, thermal, antimicrobial and release properties.

This research has revealed the promising, green and one-pot approach for fabrication of antimicrobial nanohybrids based on organic nanofibers including cellulose (CNF), chitosan (CHNF), and lignocellulose (LCNF) nanofibers impregnated with silver nanoparticles (AgNPs). Lythrum salicaria extract was used as a reducing agent as well as a capping agent. Formation of the spherical AgNPs ranging between 45 and 65 nm was proved by UV-Vis spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Biomaterials supported AgNPs were characterized and compared for their morphological, thermal, release, and antimicrobial properties. The considerable influence of the phenolic compounds of L.salicaria extract on the synthesis and uniform distribution of AgNPs on nanofibers was confirmed by field emission electron microscopy (FE-SEM). Energy dispersive X-ray spectroscopy (EDX) and ICP-OES analysis of nanohybrids, reflected a high loading capacity for LCNF and also CHNF in contrast to CNF. The release of AgNPs from LCNF substrate was lower than other nanofibers but the order of antimicrobial activity of nanohybrids against E.coli and S.aureus was as this: CHNF ˃ LCNF ˃ CNF. Generally, this research suggested that the efficiency of CHNF and LCNF as immobilizing support of AgNPs is higher than CNF and L.salicaria extract was proposed as a high potential reducing and capping agent.

Design and synthesis of organic rectorite-based composite nanofiber membrane with enhanced adsorption performance for bisphenol A.

Nowadays, most of mineral-based adsorbents are powder form, which makes them inconvenient to collect and always easy to cause secondary pollution. In this work, an organic rectorite composite nanofiber membrane (SRt-PAN) was designed and prepared by electrospinning technique. The as-received composite nanofiber membranes were characterized by XRD and SEM analysis, proving the homodisperse and existence of SRt in PAN nanofiber membrane. A series of batch experiments for BPA adsorption were carried out to investigate the effect of different adsorption parameters, including initial concentration, pH, and temperature of pollutant solution. The influences of modifier dosage and adsorbent dosage on the adsorption performance were investigated as well. On the basis of the experiment results, the adsorption process could be well described by the pseudo-second-order model and the Langmuir isotherm. In addition, the thermodynamic parameters indicate that this adsorption process is exothermic and spontaneous. Moreover, compared with pure nanofiber membranes and organic rectorite powders, the resultant SRt-PAN adsorbents exhibited higher adsorption capacity, superior reusability, and adsorption stability. It is indicated that the hydrophobicity surface of organic rectorite should be the key factor to not only the intimate interfacial combination between the mineral and PAN, but also the enhancement of BPA adsorption capacity.

Self-assembly and metal-directed assembly of organic semiconductor aerogels and conductive carbon nanofiber aerogels with controllable nanoscale morphologies

A versatile and highly tunable synthesis for nanofiber aerogels based on the n-type organic semiconductor perylene tetracarboxylic diimide (PTCDI) is presented. PTCDI nanofiber aerogels are demonstrated to incorporate the organic semiconductor into a high surface area and porous morphology, and can also be graphitized to synthesize carbon nanofiber (CNF) aerogels by thermal annealing. Using this approach, CNF aerogels with variable density and crystallinity are synthesized. Furthermore, by incorporating metal salts into the synthesis, metal-directed assembly yields a variety of nanoscale morphologies. The selection of post-synthesis thermal treatment can result in metal-directed assembly of PTCDI aerogels, low crystallinity graphitic aerogels decorated with metal nanoparticles, or highly crystalline graphitic aerogels with controllable nanoscale morphologies. The high surface area and porosity afforded by the aerogel morphology coupled with the intrinsic properties of PTCDI or CNFs is important for improving their performance in a number of applications including energy storage and catalysis.

Laser Systems and Networks with Organic Nanowires and Nanofibers

AbstractThe potentialities of miniaturized laser sources are still far from being fully developed. Unprecedented opportunities are generated in this field by organic nanowires and nanofibers, which can be used as building blocks of micro‐ and nanolasers in which they combine optical gain, waveguiding, and very high versatility to create nanophotonic networks. The progress in laser devices and network architectures based on optically pumped organic light‐emitting nanowires and nanofibers is here presented, with emphasis on developed active materials, fabrication technologies, lasing mechanisms, and cavity geometries, and on achieved device performance in terms of spectral tunability, excitation threshold, and resonator quality factors. Recent examples of optical coupling of different miniaturized lasers, of their application in optical sensing, and of network lasers are presented. Future directions for research are also outlined, which include the exploration of new classes of active organic or hybrid materials within nanowires, the more in‐depth characterization of the fundamental properties of these lasers, and the use of topologically defined organic nanophotonics in network science, computing, and diagnostics.

Electrochemical Biosensing of Chilled Seafood Freshness by Xanthine Oxidase Immobilized on Copper-Based Metal–Organic Framework Nanofiber Film

ATP degradation is an important biochemical change during decomposition of seafood. Hypoxanthine and xanthine which are formed during ATP degradation process can be used for evaluation of chilled seafood freshness. Present study successfully immobilized xanthine oxidase (XOD) onto a type of biocompatible copper-based metal organic framework nanofibers (Cu-MOF) film and used it for fabrication of a hypoxanthine and xanthine electrochemical biosensor. Cu-MOF can efficiently entrap XOD, provide a suitable atmosphere for XOD biocatalysis, and ensure good electron transfer between enzyme and electrode surface. The as-prepared XOD-electrochemical biosensor demonstrated high sensitivity for both hypoxanthine and xanthine with a wide linear range (0.01 to 10 μM) and low limit of detection. During the 3-week storage stability test at 4 °C, the fabricated biosensor demonstrated good reusability (up to 100 times) and excellent storage stability for hypoxanthine and xanthine. When applied for detection of hypoxanthine and xanthine in chilled squid and large yellow croaker, the XOD-electrochemical biosensors demonstrated good recovery rates.

Flexible and Highly Sensitive Hydrogen Sensor Based on Organic Nanofibers Decorated by Pd Nanoparticles.

A highly sensitive and flexible hydrogen sensor based on organic nanofibers decorated by Pd nanoparticles (NPs) was designed and fabricated for low-concentration hydrogen detection. Pd NPs were deposited on organic nanofiber materials by DC magnetron sputtering. The temperature dependence of the sensitivity at 25 ppm H2 was characterized and discussed, and the maximum response of the sensor increased linearly with increasing measurement temperature. Performances of the hydrogen sensor were investigated with hydrogen concentration ranging from 5 ppm to 50 ppm. This sensor exhibits high sensitivity, with the response up to 6.55% for H2 as low as 5 ppm, and the output response of the hydrogen sensor increased linearly with the square root of hydrogen concentration. A cycling test between pure nitrogen and 25 ppm hydrogen concentration was performed, and the hydrogen sensor exhibited excellent consistency.

Study of Electron-Vibrational Interaction in Molecular Aggregates Using Mean-Field Theory: From Exciton Absorption and Luminescence to Exciton-Polariton Dispersion in Nanofibers

We have developed a model in order to account for electron-vibrational effects on absorption, luminescence of molecular aggregates and exciton-polaritons in nanofibers. The model generalizes the mean-field electron-vibrational theory developed by us earlier to the systems with spatial symmetry, exciton luminescence and the exciton-polaritons with spatial dispersion. The correspondence between manifestation of electron-vibrational interaction in monomers, molecular aggregates and exciton-polariton dispersion in nanofibers is obtained by introducing the aggregate line-shape functions in terms of the monomer line-shape functions. With the same description of material parameters we have calculated both the absorption and luminescence of molecular aggregates and the exciton-polariton dispersion in nanofibers. We apply the theory to experiment on fraction of a millimeter propagation of Frenkel exciton polaritons in photoexcited organic nanofibers made of thiacyanine dye.

Analytical study of fractional Bratu-type equation arising in electro-spun organic nanofibers elaboration

In this article, we present a hybrid analytical scheme, namely, homotopy perturbation transform method to achieve the solutions of the non-linear Bratu-type problem with fractional order derivatives. The Caputo type fractional derivatives are considered in the present article. He’s polynomial is used to tackle the nonlinearity which arise in our considered problem. Using the initial conditions, the numerical solutions of the problem are computed. The numerical procedure reveals that only a few iterations are needed for better approximation of the solutions, which illustrates the effectiveness and reliability of the method. Effects of fractional order derivatives on the solutions for various particular cases are depicted through graphs.

Synthesis of zirconia, organic and hybrid nanofibers for reinforcement of polymethyl methacrylate denture base: evaluation of flexural strength and modulus, fracture toughness and impact strength

Objective The objective of this study was to synthesize and characterize inorganic zirconium oxide (ZrO2), organic [bisphenol A diglycidyl ether dimethacrylate (Bis-GMA)+triethylene glycol dimethacrylate (TEGDMA)+polyethylene glycol dimethacrylate (PEGDMA)] and hybrid (ZrO2+ Bis-GMA + TEGDMA) nanofibers and the use of these nanofibers for improving flexural strength (FS) and flexural modulus (FM), fracture toughness (FT) and impact strength (IS) of polymethyl methacrylate (PMMA) resin. Materials and methods Inorganic, organic and hybrid nanofibers were synthesized by wet electrospinning technique. The study was divided into four groups according to the type of added nanofibers (6%) to the heat-curing PMMA denture base resin; control group: PMMA without nanofibers, inorganic group: PMMA with silanized ZrO2 nanofibers, organic group: PMMA with Bis-GMA/TEGDMA/PEGDMA nanofibers and hybrid group: PMMA with ZrO2/Bis-GMA/TEGDMA nanofibers. According to ISO FDIS 20795-1:2013, three-point bending test was used to measure FS, FM and FT for each group (n = 10). According to ISO 197-A1: 2005, impact tester was used to measure IS for each group (n = 10). One-way analysis of variance was used for statistical significance between groups and post-hoc (Tukey's test) was used for multiple comparisons. P value less than or equal to 0.01 was considered significantly different. Results The synthesized pure forms of three types of nanofibers were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. Nanofibers-reinforced groups (ZrO2, hybrid and organic, respectively) recorded high means % than that of the control group as follows: 205, 184 and 170% for FS (MPa), 184, 149 and 120% for FM (GPa), 210, 189 and 177% for FT (MPa m1/2) and 151, 180 and 176% for IS (KJ/m2). In each of the four tested mechanical properties, one-way analysis of variance revealed a significant differences between the studied groups (P = 0.000) and post-hoc (Tukey's test) revealed that nanofibers-reinforced groups were markedly significantly higher than control group (P = 0.000). Conclusion ZrO2, Bis-GMA/TEGDMA/PTEGDMA and ZrO2/Bis-GM/TEGDMA hybrid nanofibers synthesized by electrospinning technique improved significantly FS, FM, FT and IS of PMMA resin (P = 000).

Ultra-permeable polyamide membranes harvested by covalent organic framework nanofiber scaffolds: a two-in-one strategy.

Polyamide-based thin-film composite nanofiltration membranes are widely used for potable water decontamination, brackish water desalination and wastewater reutilization. However, enhancing the water permeance of the polyamide layer within the thin-film composite nanofiltration membrane still remains a great challenge, because of the relatively large thickness and high transport resistance of the polyamide layer produced by intractable interfacial polymerization. Herein, we reported a two-in-one strategy to prepare ultra-permeable nanofiltration membranes via covalent organic framework (COF) nanofiber scaffold mediated interfacial polymerization. The highly porous and hydrophilic COF nanofiber scaffolds enhanced the controlled release of amine monomers, leading to ultrathin polyamide layers. Also, the relatively smooth COF nanofiber scaffolds can be spontaneously evolved into rugged and uneven architectures during interfacial polymerization, providing rough substrates for enlarging the actual areas of polyamide layers. Therefore, the increased areas of polyamide layers were employed as additional water permeable domains. Arising from the synergetic effect of the ultrathin and increased water permeation domains, the produced membranes exhibit exceptional nanofiltration performance with a water permeance of up to 31.1 L m-2 h-1 bar-1 and a Na2SO4 rejection rate of about 95%, outperforming most other nanofiltration membranes. This highly accessible technique opens a new avenue for the design and engineering of ultra-permeable thin-film composite nanofiltration membranes, highlighting its great potential in providing clean water.

Nanoarchitectured metal–organic framework-derived hollow carbon nanofiber filters for advanced oxidation processes

MOF-derived hollow carbon nanofiber filters (HCNFs) are designed as an efficient peroxymonosulfate catalytic reactor for the removal of organic pollutants.

Facile Fabrication of Magnetic Metal–Organic Framework Nanofibers for Specific Capture of Phosphorylated Peptides

A kind of magnetic metal–organic framework (mag-MOF) nanofibers was presented; the inorganic hydroxyapatite nanowires functionalized with magnetic nanoparticles on the surface acted as the scaffold...

Enhancing the supercapacitive performance of Nickel based metal organic framework-carbon nanofibers composite by changing the ligands

The present work offers a facile, cost-effective and green strategy to efficiently regulate the pore dimensions and surface morphology of Nickel based Metal organic frameworks (MOFs) using three carboxylic acids of different molecular lengths. The material characterization studies revealed that Ni MOF with longer organic linker i.e., 4, 4‘-Biphenyl dicarboxylic acid (Ni-BPDC) exhibits large surface area and large pore dimensions which enables swift movement of electrolyte ions through the framework. Also, the interconnected network of Ni-BPDC nanoplates results into continuous charge distribution, thus delivering better electrochemical performance amongst three Ni MOFs. Furthermore, to enhance the electrochemical performance of Ni-BPDC, it was combined with carbon nanofibers (CNF) and the electrochemical characterization studies of Ni-BPDC/CNF as a single electrode material shows its high specific capacity of 250.6 mA h g−1 at current density of 1 A g−1. To further explore real time application of Ni-BPDC/CNF composite, a symmetric supercapacitor device was fabricated in a Swagelok cell and it is found to deliver excellent energy density of 48.1 Wh kg−1 and power density of 1064.7 W kg−1 at an operating voltage of 1.2 V. Besides, it manifests a long cycle life with only 8% deterioration of initial specific capacity after 5000 cycles. We believe that these encouraging results not only suggests the possibility for tuning properties of existing MOFs using different organic linkers but also provides an efficient way to develop hybrid MOF composites for future energy storage applications.

Surface Roughness, Hardness, Color Stability, Water Sorption and Water Solubility of PMMA Denture BaseMaterial Reinforced with SynthesizedInorganic, Organic, and Hybrid Nanofibers

Objective: The objective of the study was to assess surface roughness, microhardness, colorstability, water sorption and water solubility of polymethyl methacrylate (PMMA) denture base resinreinforced with inorganic {silanized ZrO2}, organic {Bisphenol A diglycidyl ether dimethacrylate(Bis-GMA)+Triethylene glycol dimethacrylate (TEGDMA)+Polyethylene glycol dimethacrylate(PEGDMA)} and hybrid {silanized ZrO2+Bis-GMA+ TEGDMA} Nanofibers.Materials and Methods: The study was divided into four groups according to the addednanofibers (6wt%) to heat curing PMMA denture base material; Control group: PMMA denturebasematerial without reinforcing nanofibers, Inorganic group: PMMA denture-base material withsilanized ZrO2 nanofibers, Organic nanofibers group: PMMA denture-base material with Bis-GMA/TEGDMA/PEGDMA nanofibers and, Hybrid nanofibers group: PMMA denture-base material withsilanized ZrO2/Bis-GMA/TEGDMA nanofibers. For each group, 10 specimens were prepared andtested for surface roughness, microhardness, water sorption and water solubility. For each group11 specimens were prepared and tested for color stability. Surface roughness was measured byoptical method. Digital Microhardness tester was used to measure Vickers microhardness. Colorstability was evaluated according to ISO/FDIS 20795-1 and ISO 7491, using a Portable ReflectiveSpectrophotometer. Water sorption (WSP) and water solubility (WSL) were performed accordingto ISO/FDIS 20795-1. One-way ANOVA was used for comparison between groups and Post-Hoctest (Tukey’s tests) was used for multiple comparisons. P-value different.Results: One-way ANOVA revealed insignificant differences between the studied groups insurface roughness (p=0.168) and color stability (p=0.806). Significant differences were found in microhardness (p=0.000), WSP (p=0.000) and WSL (p=0.000). Post-Hoc (Tukey’s test) revealedthat: 1) microhardness means of nanofibers-reinforced groups were markedly significantly higherthan control group (p=0.000). 2) WSP of organic nanofibers reinforced group was significantlylower than that of control (p=0.008), hybrid (p=0.001) and inorganic (p=0.000) groups that werenot significantly different from each other (p≥0.243). 3) WSL of ZrO2 nanofibers reinforced groupwas significantly higher than control, organic, and hybrid groups (p=0.000). However, the controlgroup was not significantly different from organic (p=0.992) and hybrid (P=0.018) groups. Organicgroup was significantly lower than hybrid group(p=0.009).Conclusions: Addition of 6% nanofibers prepared by electrospinning technique to PMMAdenture resin significantly enhanced microhardness. Surface roughness and color stability were notaffected. Water sorption was significantly reduced with organic nanofibers, but was not affected withZrO2 and hybrid nanofibers. The highest water solubility for nanofibers reinforced groups recordedin this study was (0.46±0.04μg/mm3) which is nearly one third of the ISO limit (1.6μg/mm3).