Electrospinning Academic News

Preparation and characterization of Lu2SiO5:Ce3+ luminescent ceramic fibers via electrospinning 2021-03-18

Cerium-doped lutetium oxyorthosilicate (Lu2SiO5:Ce3+, or shortly LSO:Ce) luminescent ceramic fibers were synthesized by the sol–gel process followed with electrospinning in the present research. Polyvinyl butyral (PVB) was used as a spinnable carrier and anhydrous system availed the efficient generation of the composite fibers. The phase of Lu2SiO5 starts to appear at 1100 °C based on XRD analysis. After annealed at 1200 °C for 4 h, all samples with different cerium doping concentrations show a pure phase of LSO with a well-crystallized structure. The annealed samples retain smooth surfaces and uniform morphologies. LSO:Ce fibers thus prepared exhibit a strong emission peak located at about 403 nm, corresponding to the Ce3+ 5d1→4 f1 transitions. LSO:1%Ce fibers exhibit the most intense emission among the samples doped with different cerium concentrations, which also present a much stronger emission than that of LSO:1%Ce powders. X-ray excited luminescence (XEL) spectrum shows that LSO:

Application of silver nanoclusters in electrospun fibers 2021-03-18

The purpose of this study is to prepare multifunctional polymer fibers. We report a simple and controllable method for in situ synthesis of Ag nanoclusters (NCs) in electrospun polymer fibers via a photochemical reaction. The prepared composite polymer fibers emit pink luminescence and the luminescence property can be optimized by pH and Ag(I) precursor concentration. The as-prepared Ag NCs in electrospun polymer fibers were mainly Ag2–5 with a quantum yield of 6.81% and a lifetime of 2.29 ns. The in situ growth of Ag NCs avoids excessive surface modifications which may cause the aggregation of Ag NCs in many ex situ assembly methods. The combination of Ag NCs with polymer fibers greatly improves the stability of Ag NCs and broadens their applications. The storage of Ag NCs becomes facilitative due to the formation of bulky mat. Furthermore, these luminescence composite polymer fibers show strong antibacterial activity against Staphylococcus aureus (S. aureus).

Composite nanofibers were prepared by electrospinning gel method 2021-03-18

Luminescent polyimide (PI)/europium nanofibers have been successfully prepared by electrospinning combined with an in situ sol–gel technique. The possible reaction mechanism of the simultaneous imidization of polyamide acid and gelation of europium phase was analyzed by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The results showed that chemical coupling and noncovalent interaction existed between the polymer and the europium which formed during the preparative process. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electronic spectroscopy (SEM) studies also indicated the successful incorporation of europium into PI matrix and various morphologies could be achieved by controlling the calcination temperature and the europium content. Nanofibers with necklace-like structures were obtained after calcination under high temperatures. These PI/europium nanofibers were further demonstrated to have strong fl

Electrospinning synthesis and luminescent properties of Lu2O3:Eu3+ nanofibers 2021-03-18

One-dimensional Lu2O3:Eu3+ nanofibers were prepared by electrospinning followed by high-temperature calcinations. Thermogravimetric and differential thermal analysis, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, photoluminescent spectra and decay curves were used to characterize the samples. Results showed that samples began to crystallize at ∼500 °C and crystallized completely around 1000 °C. The average diameter of nanofibers (1000 °C annealed) was about 55 nm and the particle size of Lu2O3:Eu3+ increased with increasing annealing temperature. Under ultraviolet excitation, nanofibers exhibited typical red emission of Eu3+ in Lu2O3. The effect of heat-treatment temperature on luminescent properties of nanofibers was also discussed.

Electrospinning film as a self-powered sensing platform 2021-03-18

The sensitive detection of low frequency small accelerations is particularly desirable in seismic prediction, wave energy utilization and dam/bridge damage monitoring. In this work, we report for the first time the electrospinning of polyvinylidene fluoride/carbon dots (PVDF/CDs) nanofibers and their piezoresponse under different acceleration rate. The desirable nanofibrous mats, with thin and smooth morphology, are acquired by changing spinning parameters, and β-phase crystal content is improved with increasing introduction of CDs. At an acceleration rate of 6 m/s2, frequency of 1.6 Hz and applied force of 35 N, the maximum open-circuit voltage density of 55.6 V cm−3, and short-circuit current density of 2.1 μA cm−3 are achieved for PVDF/CDs fiber with 1% (wt/v) CDs loading. In particular, the fiber mat is tested with detection sensitivity of acceleration change up to 0.4 m/s2 for potential as an acceleration sensor. Moreover, CDs not only improve the piezoresponse of PVDF fiber, but

Electrospinning fabrication and luminescent properties of SrMoO4:Sm3+ nanofibers 2021-03-18

Samarium ions doped strontium molybdate (SrMoO4:Sm3+) nanofibers (NFs) were fabricated by a simple electrospinning process. The obtained SrMoO4:Sm3+ NFs are composed of scheelite-type tetragonal SrMoO4 phase, and the NFs have an average diameter of ca. 90 nm. Under 275 nm ultraviolet (UV) excitation, the NFs show an orange-red fluorescent property symbolized by a characteristic emission (606 nm) resulting from the 4G5/2 → 6H7/2 energy level transition of Sm3+. And the photoluminescence (PL) emissi on intensity of the SrMoO4:Sm3+ NFs is superior to that of the nanoparticles (NPs) counterpart under the same doping concentrations. The effect of Sm3+ concentrations on the 4G5/2 → 6H7/2 emission intensity was also investigated. The result reveals that the concentration quenching will occur when the Sm3+ content exceeds 2 at.%. In other words, the SrMoO4:Sm3+ NFs have an optimal luminescent performance under such a doping concentration.

Preparation and luminescent properties of europium-doped yttria fibers by electrospinning 2021-03-18

Sub-micrometer-sized fibers of europium-doped yttria (Y2O3:Eu3+) were prepared by electrospinning followed by high-temperature calcinations for the first time. The fibers were with diameters of 200–400 nm and lengths of several 10 μm and cubic in phase. The spectral properties of the Y2O3:Eu3+ fibers were studied, in contrast with those of bulk powders. The results indicated that in the present Y2O3:Eu3+ fibers the excited charge transfer band had slightly blue shift in comparison with that in the bulk due to weaker covalence of Eu–O bonds. In addition, both of the lifetimes of the 5D1 and 5D0 states in the fibers became shorter than that in the bulk due to improved nonradiative transition rates.

Hierarchical Assembly of Atomically Precise Metal Clusters as a Luminescent Strain Sensor 2021-03-18

We demonstrate the formation of a versatile luminescent organo-inorganic layered hybrid material, composed of bovine serum albumin (BSA)-protected Au30 clusters and aminoclay sheets. X-ray diffraction revealed the intercalation of Au30@BSA in the layered superstructure of aminoclay sheets. Coulombic attraction of the clusters and the clay initiates the interaction, and the appropriate size of the clusters allowed them to intercalate within the lamellar aminoclay galleries. Electron microscopy measurements confirmed the hierarchical structure of the material and also showed the cluster-attached clay sheets. Zeta potential measurement and dynamic light scattering probed the gradual formation of the ordered aggregates in solution. The hybrid material could be stretched up to 300% without fracture. The emergence of a new peak in the luminescence spectrum was observed during the course of mechanical stretching. This peak increased in intensity gradually with the degree of elongation or stra

Production of biohybrid protein/PEO scaffolds by electrospinning 2021-03-18

Electrospun polymeric micro‐ and nanofibers offer the opportunity to reproduce the filamentous structure of the extracellular matrix in native tissues. The ability to electrospin extracellular matrix proteins offers the additional benefit of being able to create a chemical and structural microenvironment for cells in order to influence their behavior during scaffold seeding and tissue formation. This offers significant advantages over unspecific protein adsorption or functionalisation with adhesion promoting peptide sequences. However, producing electrospun fibers from pure protein solutions remains difficult and costly. A more accessible approach is to introduce proteins into electrospun fibers by blending synthetic polymer solutions with selected extracellular matrix proteins. The correct choice of polymer also makes the usage of toxic and denaturing solvents unnecessary. In this study we have investigated the production process for and the suitability of protein/PEO fibers, specifi

Porous Chitin Microbeads for More Sustainable Cosmetics 2021-03-18

The microbead form is a material architecture that is promising for use in biomedical and cosmetic applications; however, the use of petroleum-based microbeads (i.e., plastics) has raised significant environmental concerns in recent years. Microbeads prepared from renewable polymers could represent a sustainable alternative to these synthetic microbeads. This work explores the use of chitin in preparing biodegradable, biocompatible microbeads of low toxicity. Chitin microbeads were synthesized using the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]); the IL was used to both extract chitin directly from waste shrimp shell and to prepare the porous microbeads by coagulation in polypropylene glycol (PPG). The effects of biopolymer source and bead-preparation parameters on the formation of beads were investigated, as well as the effects of the drying conditions on the dry bead structure. It was found that IL-extracted chitin could be used to prepare beads of homogeneo

Synthesis and characterization of calcium zirconate nanofibers produced by electrospinning 2021-03-18

Calcium zirconate fibers were produced by electrospinning and characterized in this work. The solution was prepared from zirconium and calcium salts, using polyvinyl-pyrrolidone (PVP) as processing aid. The decomposition of the organic fraction and crystallization of calcium zirconate were followed by thermogravimetry and differential scanning calorimetry (TG/DSC). Raman Spectroscopy was used to measure the vibrational modes in the green as well as in the calcined fibers. The final phase composition was studied by means of X-ray diffraction (XRD). The fiber morphology was investigated by confocal laser scanning microscopy (CLS) and scanning electron microscopy (SEM). The formation reaction of calcium zirconate was observed at about 740 °C. Highly crystalline fibers were obtained already at 800 °C, but the crystallinity and calcium zirconate yield improved when the temperature was increased to 1000 °C.

Palladium/Carbon Nanofibers by Combining Atomic Layer Deposition and Electrospinning for Organic Pollutant Degradation 2021-03-18

As organic dyes are a major source of pollution, it is important to develop novel and efficient heterogeneous catalysts with high activity for their degradation. In this work, two innovative techniques, atomic layer deposition and electrospinning, were used to prepare palladium nanoparticles (Pd NPs) supported on carbon nanofibers (CNFs). The sample morphology was investigated using scanning and transmission electron microscopy. This showed the presence of nanofibers of several micrometers in length and with a mean diameter of 200 nm. Moreover, the size of the highly dispersed Pd NPs was about 7 nm. X-ray photoelectron spectroscopy visually validated the inclusion of metallic Pd. The prepared nano-catalysts were then used to reduce methyl orange (MO) in the presence of sodium borohydride (NaBH4). The Freundlich isotherm model was the most suitable model to explain the adsorption equilibrium for MO onto the Pd/CNF catalysts. Using 5 mL MO dye-solution (0.0305 mM) and 1 mL NaBH4 (0.026 m

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