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The treatment of oily wastewater remains a technological challenge. Membrane separation methods can offer solutions with high throughput and low operating cost if suitable membranes can be developed. In this work, an electrospun polymer composite membrane containing metal–organic framework (MOF) particles and carbon nanotubes (CNTs) is presented, which performs both high water flux and high separation efficiency. Polyacrylonitrile (PAN), which has excellent fiber-forming properties, is used as the polymer matrix. The MOF zeolitic imidazole framework-8 (ZIF-8) increases membrane hydrophilicity and imparts nanopores. The MOF particles are tightly associated with CNTs, increasing the MOF binding and providing mechanical stability and increased surface area to the composite fiber membrane. The result is a high-flux, high-separation efficiency, and recyclable polyacrylonitrile/zeolitic imidazolate framework-8/carbon nanotube (PAN/ZIF-8/CNT) nanofiber membrane. The membrane has a high water contact angle (WCA > 130°) and exhibits underwater oleophilicity and underoil hydrophobicity. The PAN/ZIF-8/CNT membrane has a hierarchical porous structure of microscale and nanoscale channels, resulting in good porosity that greatly improves oil–water separation performance. The membrane has a high separation flux of 2139 L m–2 h–1 for oil–water emulsion in a gravity-fed apparatus and excellent oil/water separation efficiency (>98.5%). In addition, even under acidic, alkaline, saline, and abrasive conditions, the prepared membrane also exhibits excellent hydrophobic and oleophilic properties. This work offers prospects for water purification and oily wastewater remediation. [ABSTRACT FROM AUTHOR]

Oil pollution has always been an important issue affecting the ecological and residential environment, and the development of a highly efficient oil/water separation membrane has become a hot topic. In this paper, Janus polyacrylonitrile (PAN) nanofiber membranes (PNM) were prepared by co-blending hydrophilic SiO2 nanoparticles, carbon nanotubes (CNTs) doped with PAN (PNM-SiO2 and PNM-CNT, respectively) and then using sequential multilayer electrospinning. The existence of electrostatic mutual gravitational force between SiO2 and CNTs makes the binding between the multilayer membranes exist more firmly, which is conducive to withstand the osmotic pressure brought by the liquid. In addition, Janus PAN membranes have different wetting properties; they have a micro/nanopore structure that forms a permeable channel for liquids, thus enabling efficient separation of water-in-oil and oil-in-water emulsions, which separates oil/water emulsions with flux as high as 2188 L m–2 h–1 and separation efficiency as high as 99.8%. This experiment further develops the application of Janus membranes in oil/water separation. [ABSTRACT FROM AUTHOR]

In recent years, rare earth complexes have become famous for their unique luminescence characteristics, such as clear emission bands, long lifetimes, and high luminous quantum efficiency. Since lanthanide ions have relatively small absorption areas in the ultraviolet region, they absorb light weakly. However, the excitation can be improved via coordination with organic ligands and subsequent energy transfer from the ligand triplet state to a coordinated metal ion. Electrospinning is a processing method that can readily combine rare earth complexes with matrix materials, to obtain fiber membranes with high fluorescence efficiency and stable mechanical properties. Here, we report the application of fluorescent nanofibers to color-tunable materials and oxygen sensing materials by discussing the electrospinning techniques used to produce electrospun nanofibers containing lanthanide complexes. We then focus on the mechanism of luminescence of fluorescent nanofibers, discussing polymer-based membranes and ceramic-based membranes based on the main constituent materials of the fiber membranes. [ABSTRACT FROM AUTHOR]

Abstract: Nanofiber poly(ε-caprolactone) (PCL) scaffolds were fabricated by electrospinning, and their ability to enhance the osteoblastic behavior of marrow stromal cells (MSCs) in osteogenic media was investigated. MSCs were isolated from Wistar rats and cultured on nanofiber scaffolds to assess short-term cytocompatibility and long-term phenotypic behavior. Smooth PCL substrates were used as control surfaces. The short-term cytocompatibility results indicated that nanofiber scaffolds supported greater cell adhesion and viability compared with control surfaces. In osteogenic conditions, MSCs cultured on nanofiber scaffolds also displayed increased levels of alkaline phosphatase activity for 3weeks of culture. Calcium phosphate mineralization was substantially accelerated on nanofiber scaffolds compared to control surfaces as indicated through von Kossa and calcium staining, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Increased levels of intra- and extracellular levels of osteocalcin and osteopontin were observed on nanofiber scaffolds using immunofluorescence techniques after 3weeks of culture. These results demonstrate the enhanced tissue regeneration property of nanofiber scaffolds, which may be of potential use for engineering osteogenic scaffolds for orthopedic applications. [Copyright &y& Elsevier]

In this study, transparent membranes containing luminescent Tb3+ and Eu3+ complex-doped silica nanoparticles were prepared via electrospinning. We prepared the electrospun fibrous membranes containing Tb(acac)3phen- (acac = acetylacetone, phen = 1,10-phenanthroline) and/or Eu(tta)3phen- (tta = 2-thenoyltrifluoroacetone) doped silica (M-Si-Tb3+ and M-Si-Eu3+) and studied their photoluminescence properties. The fibrous membranes containing the rare earth complexes were prepared by electrospinning. The surface morphology and thermal properties of the fibrous membrane were studied by atomic force microscopy (AFM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Fluorescence spectroscopy was used to characterize the fluorescence properties of the membranes. During the electrospinning process, the PVDF transitions from the α phase to the β phase, which exhibits a more rigid structure. The introduction of rigid materials, like PVDF and silica, can improve the fluorescence properties of the hybrid materials by reducing the rate of nonradiative decay. So the emission spectra at 548 nm (Tb) and 612 nm (Eu) were enhanced, as compared to the emission from the pure complex. Furthermore, the fluorescence lifetimes ranged from 0.6 to 1.5 ms and the quantum yields ranged from 32% to 61%. The luminescent fibrous membranes have potential applications in the fields of display panels, innovative electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

A novel anhydrous preparation of silica (SiO2)-encapsulated terbium (Tb3+) complex nanoparticles has been investigated. The SiO2-Tb3+ nanoparticles are incorporated in electrospun polyvinylpyrrolidone hybrid nanofibers. Transmission electron microscopy confirms that Tb3+ complexes are uniformly and stably encapsulated in or carried by nanosilica. The influence of pH on the fluorescence of Tb3+ complexes is discussed. The properties, composition, structure, and luminescence of the resulting SiO2–Tb3+ hybrid nanoparticles are investigated in detail. There is an increase in the fluorescence lifetime of SiO2–Tb3+ nanoparticles and SiO2–Tb3+/polyvinylpyrrolidone (PVP) hybrid nanofibers compared with the pure Tb3+ complexes. Due to the enhanced optical properties, the fluorescent hybrid nanofibers have potential applications as photonic and photoluminescent materials. [ABSTRACT FROM AUTHOR]

Patients in hospital environments are susceptible to bacterial colonization, which can lead to infections. In this study, electrospun fibers were manufactured using poly(vinyl alcohol) (PVA) crosslinked with citric acid (CA) and incorporating the ionic liquid (IL) 1-hexadecyl-3-methylimidazolium chloride (C 16 MImCl) to prevent microbial growth and biofilm formation. The presence of CA and IL reduced the surface tension of the PVA solution (12% w/v) from 52.07 mN/m to 35.84 mN/m. CA was introduced into PVA solutions, and the resulting fibers were thermally crosslinked through esterification between PVA hydroxyl groups and CA. X-ray photoelectron spectroscopy (XPS) confirmed the presence of IL on the fiber surfaces. The IL acted as a surfactant, imparting plasticity to the electrospun fibers and enhancing homogeneity and mechanical properties. Before crosslinking, the PVA/CA/IL fibers exhibited an elongation at break (%) of approximately 140%, a tensile strength of 5.3 MPa, and an elastic modulus of 18.2 MPa. After cross-linking, the elongation at break reduced to 86%, the tensile strength increased to 7.6 MPa, and the elastic modulus increased to 88 MPa. Mechanical measurements confirmed the thermal crosslinking of the fibers, primarily because of the increased elastic modulus. Adhesion and proliferation tests with Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) indicated reduced bacterial adhesion and growth on the PVA/CA/IL fibers. Antimicrobial assays further confirmed a 50.73% and 69.42% increase in bactericidal activity against S. aureus and P. aeruginosa , respectively. The PVA/CA/IL fibers exhibit promising potential for producing antimicrobial materials to prevent the attachment and proliferation of microbial strains on solid surfaces. • The ionic liquid 1-hexadecyl-3-methylimidazolium was electrospuned with poly(vinyl alcohol)/citric acid. • The ionic liquid improved the electrospinnability of the polymer solutions. • The fibers were thermally cross-linked through esterification reaction. • The fibers containing the ionic liquid promoted anti-adhesive and antimicrobial properties. [ABSTRACT FROM AUTHOR]

Poly(ε-caprolactone) (PCL) is a hydrophobic and cytocompatible aliphatic polyester that has been used to produce PCL-based nanofibrous for both wound healing and tissue repair. However, the high hydrophobicity and low water adsorptive have been challenges for developing PCL-based materials for use in tissue engineering field. Here, we report a new polymer (a hydrophilic amino-functionalized tannin (TN)) that is associated with PCL for developing PCL-TN blends at different PCL:TN weight ratios (100:0, 95:5, 85:15 and 78:22). PCL:TN ratio may be tuned to modulate hydrophilicity and cytocompatibility of the nanofibers. The neutralization step and surface wettability played an important role in the attachment of human adipose-derived stem cells (ADSC cells) on PCL-TN membranes. Also, fluorescence images confirmed great proliferation of ADSC cells on the PCL-TN electrospun surfaces. Yet, neutralized PCL-TN nanofibers promoted bactericidal activity against Pseudomonas aeruginosa. These membranes have potential to be used as scaffolds for tissue engineering purposes. [ABSTRACT FROM AUTHOR]

In this work, a luminescent lanthanide complex, namely, Eu(tta) 3 phen (Eu = europium, tta = 2-thenoyltrifluoroacetone, phen = 1, 10-phenanthroline) is used as a luminescent dopant to prepare fluorescent nanofiber films. The resulting nanofibers (CS/PEO-SiO 2 @Eu(tta) 3 phen) are composed of chitosan and polyethylene oxide containing silica nanoparticles, encapsulating the Eu(tta) 3 phen. The nanofibers are stabilized by treatment with sodium bicarbonate (NaHCO 3) aqueous solution as neutralizer and then repeatedly washed with deionized water. A more stable Na-CS/PEO-SiO 2 @Eu(tta) 3 phen fiber film is obtained as a fluorescence sensor for Cu2+ ions. The Na-CS/PEO-SiO 2 @Eu(tta) 3 phen has high sensitivity, and a wide detection range. The response is linear in the concentration range from 10 to 90 μmol/L, and the detection limit is 0.826 μmol/L. In addition, Na-CS/PEO-SiO 2 @Eu(tta) 3 phen nanofiber film can be used as a recyclable sensor for the detection of Cu2+ ions in aqueous solution due to its good recyclability, selectivity and rapid optical response. • CS/PEO-SiO 2 @Eu(tta) 3 phen film is stabilized by neutralization with weak base. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film can be quenched after Cu2+ solution is dropped on it. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film is capable of accurately detecting 10–90 μmol/L of Cu2+, LOD is 0.826 μmol/L. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film can still be used as a Cu2+ sensor after 5 cycles of use. [ABSTRACT FROM AUTHOR]

[Display omitted] • HFPNM undergoes fluorescence quenching upon contact with Cu2+. • HFPNM is capable of accurately detecting 100–1000 nmol/L of Cu2+. • HFPNM can still be used as a Cu2+ sensor after 5 cycles of use. • HFPNM have the advantages of high detection sensitivity and environmental friendliness for recycling compared to other Cu2+ sensors. Cu2+ contamination in drinking water poses a threat to humans and the environment, and high concentrations of Cu2+ in human blood can induce disease. In recent years, fluorescence sensing of Cu2+ prepared from rare earth elements has been widely used for the accurate detection and quantification of Cu2+. In this paper, we report that europium (Eu), 4,4′,4-trimethyltriphenylamine (TTA), and 1,10-phenanthroline (Phen) undergo a complexation reaction to form the Eu(TTA) 3 Phen complex, which is loaded on SiO 2 nanoparticle to form SiO 2 @Eu3+. We use electrospinning of SiO 2 @Eu3+ and polyacrylonitrile (PAN) co-blended solutions to prepare PAN fluorescent nanofiber membranes (FPNM). FPNM are hydrolyzed hydrolysis to obtain Cu2+ sensors (HFPNM). The super hydrophilic surface of HFPNM undergoes fluorescence quenching upon contact with Cu2+. HFPNM is capable of accurately detecting 100–1000 nmol/L of Cu2+. Moreover, EDTA can be used as a reversible on/off switch for detection, and HFPNM can still be used as a Cu2+ sensor after 5 cycles of use. The HFPNM have the advantages of high detection sensitivity and environmental friendliness for recycling compared to other Cu2+ sensors. Fluorescent nanofibers can be combined with bio-nanotechnology allowing for promising future applications in Cu2+ detection and wearable smart fabrics. [ABSTRACT FROM AUTHOR]

Ecovio® is a hydrophobic, biodegradable, and synthetic polymer blend composed of poly(butylene adipate- co -terephthalate) and poly(acid lactic) polyesters. It is soluble in solvents of low polarity, being a challenge to obtaining thin and homogeneous electrospun Ecovio® fibers. Ecovio® blend solutions do not have electrospinnability due to the low viscosity and electrical conductivity. For overcoming this disadvantage, Ecovio® and Tween 20 were associated with a binary 85/15 chloroform/formic acid mixture. The formic acid (15 vol%) and Tween 20 (1.0 v% concerning the total solution volume) increased the Ecovio® electrospinnability, promoting thin fibers (average diameter of 253 nm). Tween 20 (1.0% v/v) reduced the surface tension from 29.50 to 28.92 mN/cm and increased the electrical conductivity and viscosity from 0.85 to 2.03 μS/cm and 26.02–27.13 mPa s. The solution parameters were adjusted, imparting Ecovio® solution electrospinnability. The Tween 20 induced a wettable fiber surface that immediately absorbed a water droplet after contact, reducing the water contact angle from 125° on Ecovio® fiber (488 nm) to 0° on Ecovio®/Tween 20 fiber (253 nm). The wettable Ecovio®/Tween 20 fiber adsorbed silver ions (Ag+) from an aqueous solution, promoting a reinforced (Elastic modulus of 2136 MPa) and wettable composite fiber after Ag + reduction. The determined Ag0 content was 8 μg per composite fiber gram. Ecovio®/Tween 20 fibers stabilized the AgNPs, imparting anti-adhesive and antimicrobial properties against Staphylococcus aureus (S. aureus) and Escherichia coli. The composite filter removed bacteria from water (S. aureus at 107 CFU/mL), reaching a removal efficiency of 99.99% in the first filtration. The biodegradable and antimicrobial composite filter can replace conventional harsh chemicals that treat water, including drinking water contaminated with bacteria. [Display omitted] • Tween 20 and formic acid improved the electrospinnability of polymer blends. • Tween 20 promoted wettable surfaces that adsorb Ag + ions. • The Ag + ions are reduced, imparting a composite filter. • The AgNPs reinforced the filter, supporting an elastic modulus of 2136 MPa. • The antimicrobial filter removed bacteria (99.99%) from water at 107 CFU/mL. [ABSTRACT FROM AUTHOR]

CH/PEO-SiO 2 @Eu3+ fiber is prepared by electrospinning. Due to the fluorescence of Eu3+ complex, the film appears red under the excitation of UV-light. When the Cu2+ solution is dropped to the film, the color of the film will no longer appear red, and the fluorescence of the composite chitosan nanofibers can be quickly and sensitively quenched. [Display omitted] • CH/PEO-SiO 2 @Eu3+ nanofiber is prepared by electrospinning. • Due to the fluorescence of Eu3+ complex, the film appears red under the excitation of UV-light. • The fluorescence of the CH/PEO-SiO 2 @Eu3+ film can be quenched after Cu2+ solution is dropped on it. Trace amounts of heavy metal ions in the human body are essential for maintaining health. However, heavy metal ion excess or deficiency causes toxicity or disease. This study examines the sensitivity of luminescent europium complexes for the detection of Cu2+. Here, Eu3+ is complexed with1,10-phenanthroline (phen) and 4,4′,4-trimethyltriphenylamine (TTA) to form luminescent [Eu3+(TTA) 3 phen] complexes, encapsulated in silica (SiO 2) nanoparticles. The silica nanoparticles are then formed into a composite with a blend of chitosan and polyethylene oxide (PEO), to make electrospun nanofibers. The combination of Eu3+ complexes with SiO 2 nanoparticles doped in chitosan enhances the fluorescence performance. Photophysical measurements show that when the Cu2+ concentration is 100 μmol/L, the fluorescence of the composite chitosan nanofibers can be quickly and sensitively quenched, and that concentrations as low as 10 μmol/L Cu2+ can be detected. Furthermore, the use of chitosan and PEO to prepare the material makes these new fluorescence-based copper sensing materials suitable for Cu2+ detection in biological systems. [ABSTRACT FROM AUTHOR]