scholarly journals Structural and Thermophysical Studies of Composite Na-Cobaltite Electrospun Nanofibers

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Fatima-tuz-Zahra ◽  
M. Anis-ur-Rehman
Keyword(s):  
Thermal Conductivity ◽  
Flow Rate ◽  
Sol Gel ◽  
Electrospun Nanofibers ◽  
Processing Parameters ◽  
Electrospinning Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Electrospinning Technique ◽  
Energy Applications

Polymeric nanofibers have been produced in the last few years by electrospinning of polymer solutions. Polyvinyl alcohol (PVA) was the selected polymer for the preparation of nanofibers. Processing parameters like flow rate, needle gauge, needle to collector distance, and molarity of the solution have been optimized during electrospinning process. Sol-gel method has been used for the preparation of thermoelectric cobaltite nanoparticles having composition NaCoO2. Sol-gel combined electrospinning technique was used to prepare the composites of the NaCoO2 with PVA nanofibers. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for the structural analysis of the prepared samples. Scanning electron microscopy (SEM) was used to observe the morphology of the prepared fibers. SEM micrographs showed that, by increasing the flow rate, diameter of the fibers increased from 185 nm to 200 nm. Two-probe method and Advantageous Transient Plane Source (ATPS) were used to study the electrical and thermal transport properties, respectively. Thermal conductivity and electrical conductivity showed a direct dependence on temperature. It was observed that particles, sample has lower thermal conductivity (0.610 W/m-K) as compared to that of composite nanofibers (1.129 W/m-K). The measurements reported are novel and are useful for energy applications.

PVA-Ketoprofen Nanofibers Manufacturing Using Electrospinning Method for Dissolution Improvement of Ketoprofen

2013 ◽  
Vol 737 ◽  
pp. 166-175 ◽  
Author(s):  
Jessie S. Pamudji ◽  
Khairurrijal ◽  
Rachmat Mauludin ◽  
Titi Sudiati ◽  
Maria Evita
Keyword(s):  
Dissolution Rate ◽  
Solid Dispersion ◽  
Flow Rate ◽  
Polymer Concentration ◽  
Electrospinning Process ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Electrospinning Method ◽  
Rate Improvement

Background and purpose: Ketoprofen is an NSAIDs agent which has analgesic and anti inflammation effects. Ketoprofen is classified into class II in the biopharmaceutical classification system that has a high permeability but low solubility. Hence, the absorption rate of this substance is governed by its dissolution rate. Electrospinning is a method that combine solid dispersion technology and nanotechnology. This method can be selected to enhance the dissolution rate of active substances. The aim of this research is to improve the dissolution rate of ketoprofen through the preparation of polymeric nanofiber polivinyl alcohol (PVA) containing ketoprofen using electrospinning process. Methods: Preparation of nanofibers with various of PVA-ketoprofen ratio, flow rate, and PVA concentration in the solution were accomplished using electrospinning instrument. Casting solid dispersion film were also prepared by solvent evaporation method and used as a reference. The rates of dissolution of ketoprofen from each of nanofibers, casting films, and pure ketoprofen were conducted in HCl pH 1.2 medium at 37oC. Characterization of nanofibers was carried out using Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). Results: Nanofibers which contained of PVA-ketoprofen 1:1 in ratio w/w showed a significant improvement in dissolution (p<0.05) compared to the pure ketoprofen. Meanwhile, nanofibers obtained from a solution containing 7.5 % PVA (w/v) and 4 ml/h in flow rate showed the best dissolution rate improvement and significantly different (p<0.05) with either the casting film or the pure ketoprofen. The improvement of ketoprofen dissolution was due to the increasing of surface area of nanofiber and the change of ketoprofen from crystalline into amorphous form. Conclusion: Electrospinning technique can be used to improve the dissolution rate of ketoprofen through the PVA-ketoprofen nanofiber formation by choosing the appropriate polymer concentration and manufacturing process.

scholarly journals Characterization of PVPK90 core shell nanofibers containing curcumin prepared by emulsion electrospinning process

2021 ◽  
Author(s):  
Hossein Kamali ◽  
Parisa Farzadnia ◽  
Jebraeil Movaffagh ◽  
Mohammadreza Abbaspour
Keyword(s):  
Drug Release ◽  
Organic Phase ◽  
Flow Rate ◽  
Electrospun Nanofibers ◽  
Amorphous Structure ◽  
Electrospinning Process ◽  
Core Shell ◽  
Electrospinning Technique ◽  
Disintegration Time

Abstract The pharmacological effects of curcumin (CUR) as a polyphenolic ingredient of turmeric affected by its water insolubility, poor bioavailability, and instability. The electrospun nanofibers of hydrophilic biodegradable polymer can be addressed this issue. The current study aimed to investigate the CUR-loaded core-shell PVPK90 nanofibers generated from O/W nanoemulsions. CUR-loaded PVPK90 fibers were prepared based on the central composite design and different levels of drug concentration, flow rate, amount of acetone, and organic phase percentage by electrospinning technique and their diameter and uniformity, tensile strength, wetting and disintegration time were evaluated. Then, DSC, FTIR, XRD, TEM, fluorescence microscopy, and drug release test were carried out on the optimized nanofibers. The formulation containing 6 mg/mL CUR, 30% organic phase, 0.4 mL acetone, and flow rate of 1 mL/h was selected as optimum formulation. The results were confirmed the core-shell bead-free uniform fibers at the nanometer scale. The optimum nanofiber showed a good flexibility, short wetting and disintegrating times as well as the amorphous structure. The drug release pattern indicated the rapid release of the drug within 30 min. Our findings confirm that the O/W emulsion electrospinning-based PVPK90 core-shell nanofiber would be beneficial as a novel delivery system for water insoluble drug.

scholarly journals Solvent Effects on Morphology and Electrical Properties of Poly(3-hexylthiophene) Electrospun Nanofibers

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1501 ◽  
Author(s):  
Jung-Yao Chen ◽  
Chien-You Su ◽  
Chau-Hsien Hsu ◽  
Yi-Hua Zhang ◽  
Qin-Cheng Zhang ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Field Effect Transistors ◽  
Electrospun Nanofibers ◽  
Charge Carrier Mobility ◽  
Organic Field Effect Transistors ◽  
Electrospun Nanofiber ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
The Core ◽  
Core Polymer

Herein, poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofiber-based organic field-effect transistors were successfully prepared by coaxial electrospinning technique with P3HT as the core polymer and poly(methyl methacrylate) (PMMA) as the shell polymer, followed by extraction of PMMA. Three different solvents for the core polymer, including chloroform, chlorobenzene and 1,2,4-trichlorobenzene, were employed to manipulate the morphologies and electrical properties of P3HT electrospun nanofibers. Through the analyses from dynamic light scattering of P3HT solutions, polarized photoluminescence and X-ray diffraction pattern of P3HT electrospun nanofibers, it is revealed that the P3HT electrospun nanofiber prepared from the chloroform system displays a low crystallinity but highly oriented crystalline grains due to the dominant population of isolated-chain species in solution that greatly facilitates P3HT chain stretching during electrospinning. The resulting high charge-carrier mobility of 3.57 × 10−1 cm2·V−1·s−1 and decent mechanical deformation up to a strain of 80% make the P3HT electrospun nanofiber a promising means for fabricating stretchable optoelectronic devices.

Structure and properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/poly(L-lactic acid) quasi core/sheath melt-electrospun microfibers

2018 ◽  
Vol 89 (9) ◽  
pp. 1770-1781 ◽  
Author(s):  
Huaizhong Xu ◽  
Benedict Bauer ◽  
Masaki Yamamoto ◽  
Hideki Yamane
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Tensile Tests ◽  
Processing Parameters ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Diffraction Patterns

A facile route was proposed to fabricate core–sheath microfibers, and the relationships among processing parameters, crystalline structures and the mechanical properties were investigated. The compression molded poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/poly(L-lactic acid) (PLLA) strip enhanced the spinnability of PHBH and the mechanical properties of PLLA as well. The core–sheath ratio of the fibers was determined by the prefab strip, while the PLLA sheath component did not completely cover the PHBH core component due to the weak interfacial tension between the melts of PHBH and PLLA. A rotational target was applied to collect aligned fibers, which were further drawn in a water bath. The tensile strength and the modulus of as-spun and drawn fibers increased with increasing the take-up velocities. When the take-up velocity was above 500 m/min, the jet became unstable and started to break up at the tip of the Taylor cone, decreasing the mechanical properties of the fibers. The drawing process facilitated the crystallization of PLLA and PHBH, and the tensile strength and the modulus increased linearly with the increasing the draw ratio. The crystal information displayed from wide-angle X-ray diffraction patterns and differential scanning calorimetry heating curves supported the results of the tensile tests.

Effect of Processing Parameters on the Morphology, Particulate, and Superconducting Properties of Electrospun YBCO Nanostructures

2020 ◽  
Vol 63 ◽  
pp. 89-97
Author(s):  
Saleh Eesaa Jasim ◽  
Mohamad Ashry Jusoh ◽  
Muhammad Aizat Kamarudin ◽  
Fahmiruddin Esa ◽  
Rodziah Nazlan
Keyword(s):  
Molecular Weight ◽  
Total Content ◽  
Processing Parameters ◽  
Electrospinning Process ◽  
Coarse Grained ◽  
Critical Temperatures ◽  
Electrospinning Technique ◽  
Molecular Weight Polymer ◽  
Practical Applications ◽  
Nanostructured Ceramics

Superconductivity in nanostructured ceramics offers significant advantages over the conventional coarse-grained materials in view of miniaturization of superconducting electronic devices. In this paper, we report the formation of four morphologies of superconducting YBa2Cu3O7-δ (YBCO) nanostructures by electrospinning technique using polymeric polyvinyl pyrrolidone (PVP) solutions of different molecular weight and altering the total content of the metallic precursors. The morphologies prepared using this strategy are nanorods (NRs), nanogarlands (NGs), nanohierarchical (NH), and nanoparticles (NPs). Alternating current susceptibility measurements showed high critical temperatures (TC ~90 K) for the NH YBCO synthesized using PVP of the lowest molecular weight; whereas the YBCO NRs synthesized using a higher molecular weight polymer showed the lowest TC (82 K). A relationship between the particulate properties and TC was also observed – the lower is the pore size the higher is the TC. The YBCO NGs showed the highest specific surface area (7.06 m2/g) with intermediate TC (88 K). Electrospinning process appears an effective and controllable technique to produce different nanomorphologies with intrinsic properties suitable for practical applications.

Iron and Iron-oxide on Silica Nanocomposites Prepared by the Sol-gel Method

2002 ◽  
Vol 17 (3) ◽  
pp. 590-596 ◽  
Author(s):  
G. Ennas ◽  
M. F. Casula ◽  
G. Piccaluga ◽  
S. Solinas ◽  
M. P. Morales ◽  
...  
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Gel Method ◽  
Sol Gel Method ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Nanometric Particles

γ–Fe2O3/SiO2 and Fe/SiO2 nanocomposites, with a Fe/Si molar ratio of 0.25, were prepared by the sol-gel method starting from ethanolic solutions of tetraethoxysilane and iron (III) nitrate. After gelation the xerogels were oxidated or reduced. Samples were investigated by transmission electron microscopy, x-ray diffraction, differential scanning calorimetry, and thermogravimetry. Magnetic properties of the samples were investigated at room temperature (RT) and at 77 K. Nanometric particles supported in the silica matrix were obtained in all cases. Bigger particles (10 nm) were obtained in the case of Fe/SiO2 nanocomposites with respect to the γ–Fe2O3/SiO2 samples (5–8 nm). A slight effect of sol dilution on particle size was observed only in the case of γ–Fe2O3/SiO2 nanocomposites. A superparamagnetic behavior was shown at RT only by γ–Fe2O3/SiO2 nanocomposites. Iron-based composites exhibited coercivity values higher than 700 Oe at RT.

Formation and Phase Transformation of R. F. Sputter Deposited NON-BCC 6-A15 Chromium Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
J. P. Chu ◽  
J. W. Chang ◽  
P. Y. Lee ◽  
J. K. Wu
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Working Pressure ◽  
Annealing Study ◽  
First Order Transition ◽  
Sputter Deposited ◽  
First Time

AbstractFormation and phase transformation of non-BCC δ-A15 Cr thin films prepared by R. F. magnetron sputtering have been characterized. Processing parameters such as working pressure, deposition time and temperature were found to affect the formation of δ-A15 Cr films. Using differential scanning calorimetry, we have demonstrated for the first time that the phase transformation of the δ-A15 Cr phase to the equilibrium c-BCC Cr phase is an irreversible, exothermic, first-order transition. At a heating rate of 10°C/min, the onset and peak temperatures of transformation were determined to be 428°C and 437°C, respectively. Our post-deposition annealing study by X-ray diffraction further verified the occurrence of transformation.

Synthesis of V2O5 Powders by EDTA Assistance Ultrasound Sol-Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 207-210
Author(s):  
Quan Wen ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Activation Energy ◽  
Raw Materials ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calcination Temperatures ◽  
Sol Gel Process ◽  
Ft Ir ◽  
Precursor Powders ◽  
Influence Of Ph

V2O5 powders were successfully synthesized by the EDTA assistanced ultrasound sol-gel process using NH4VO3 and EDTA, NH3•H2O as raw materials. The synthesized activation energy and the influence of pH values and the calcination temperatures on the phases and microstructures of powders were particularly investigated. The precursor powders and the V2O5 powders were characterized by X-ray diffraction (XRD), fourier transform inelectron microscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry-thermal gravimetric (DSC-TG). Results show that the obtained products exhibit good crystallization under the conditions of pH=4, calcination temperature 400~500 °C and calcination time 0.5 h during the synthesizing process. The as-prepared V2O5 powders show preferred growth orientation along (001) plane at the pH=4. By DSC analysis, the ultrasonic cavitation result in the decrease in synthesized activation energy obviously than that was prepared without ultrasonic irradiation.

Reactive atmosphere synthesis of sol-gel heavy metal fluoride glasses

1992 ◽  
Vol 7 (6) ◽  
pp. 1534-1540 ◽  
Author(s):  
A.M. Mailhot ◽  
A. Elyamani ◽  
R.E. Riman
Keyword(s):  
Heavy Metal ◽  
Sol Gel ◽  
Fluoride Glass ◽  
Metal Fluoride ◽  
X Ray Diffraction ◽  
Combustion Analysis ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heavy Metal Fluoride ◽  
Heavy Metal Fluoride Glasses

A glass based on ZrF4 was synthesized by a combination of sol-gel and reactive atmosphere processing. Infrared spectroscopy and combustion analysis show that the fluorination process reduces the concentration of organic and hydroxide impurities. Chemical changes have occurred during fluorination; this is indicated by different x-ray diffraction traces and crystallization characteristics for the fluorinated sample compared to the oxide gel product. Chemical analysis from x-ray fluorescence indicates that the fluorinated gel is chemically similar to a melted glass of the same composition. Differential scanning calorimetry gives a glass transition temperature of 290 °C and a crystallization temperature of 390 °C. These values are consistent with those expected for a fluoride glass prepared by conventional methods.

A Calcination Technology for Ultrafine La3NbO7 Powder Prepared by Sol-Gel Process

2011 ◽  
Vol 412 ◽  
pp. 271-274
Author(s):  
Ying Li ◽  
Qiang Xu ◽  
Ling Dai
Keyword(s):  
Single Phase ◽  
Sol Gel ◽  
Average Particle Size ◽  
Complex Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Acid Complex ◽  
Calcination Process ◽  
Sol Gel Process

In order to prepare ultrafine La3NbO7 powder, a potential material for thermal barrier coatings, the calcination process of La3NbO7 was studied in this paper.The precursor of La3NbO7 was synthesized by using a citric acid complex method. A calcination process had been systematically investigated. The reaction temperature was determined by differential scanning calorimetry (DSC). The phase composition of powders was characterized by X-ray diffraction (XRD), and the morphology was obtained by scanning electron microscope (SEM). The results revealed that the single-phase La3NbO7 powder could be successfully prepared while the calcination temperature exceeded 800°C and a better morphology could be maintained at 800°C for 4 hours. Considering all above, an optimum calcination scheme was adopted at 800°C for 4 hours. The as-prepared La3NbO7 powders had a grain size of about 50nm and an average particle size of about 300nm.

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