首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 406 毫秒
1.
In this study novel material PbS–graphene/TiO2 composites were prepared by sol–gel method. The “as-prepared” composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS) and Raman spectroscopic analysis. The photocatalytic activities were investigated by the degradation of methylene blue (MB) as a standard dye. We observed that coupling of PbS with TiO2 extends the photoresponse to visible region. This revealed that the excellent photoinduced charge separation abilities and transport properties of graphene make these hybrids as potential candidates for developing high-performance next-generation devices.  相似文献   

2.

Electrospun polymeric nanofibers as carriers for anticancer drugs have received a great deal of attention to treat tumor cells. This work was aimed to prepare an optimized nanofibrous sample based on poly(vinyl alcohol) (PVA)/chitosan (CS) blend, and then evaluate it containing 5-fluorouracil (5-FU) in terms of morphology, drug release, and cell culture. The electrospinning conditions to produce PVA/CS (50/50) blend nanofibers with an average diameter of approximately 150.8 nm were adjusted as follows: applied voltage 17 kV, needle tip to collector distance 60 cm, and flow rate 0.1 mL/h. The obtained results from Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) showed that there were no chemical interactions between the polymers and drug during the electrospinning process and the uniform morphology without beads. Moreover, to prolong 5-FU release from the blend nanofibers, three layered samples consisting of PVA/CS blend and poly (ε-caprolactone) (PCL) [PVA/CS-PCL 3-layers] were electrospun. On the other hand, by adding PCL in the PVA/CS blend nanofibers, the samples showed more hydrophobic property. Eventually, thiazolyl blue (MTT) assay along with NIH 3T3 cells culture proved that the sample could kill more than 80% of the cells. This formulation could be a promising candidate for cancer therapy potentially.

  相似文献   

3.
This paper reports for the first time the facile synthesis of hollow F-doped SnO2 nanofibers by solution blow spinning (SBS) and their ethanol sensing performance. The as-prepared nanofibers were characterized using scanning electron microscopy (SEM), x-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier-transform infrared spectroscopy (FTIR), and electrochemical impedance spectroscopy (EIS). The gas sensing behavior of the F-doped SnO2 nanofibers was investigated using a homemade test chamber. The results revealed the preparation of mesoporous F-doped SnO2 hollow fibers with a diameter ranging from 207 ± 43 to 355 ± 41 nm. The combination of nanocrystalline hollow structure and F doping led to fast high-responsive ethanol sensors at room temperature (RT) with good reproducibility and long-term stability. These results indicate that F-doped SnO2 hollow nanofibers are good candidates for building practical low-temperature ethanol gas sensors.  相似文献   

4.
This article reports the facile synthesis of copper sulfide (CuS)/polyaniline (PANI) nanocomposites by in situ polymerization. The composites were characterized by scanning electron microscopy (SEM), UV–visible and Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). SEM analysis showed that the metal sulfide nanoparticles were uniformly dispersed in the polymer matrix. The characteristic peaks in FTIR and UV–vis spectra of PANI were found to be shifted to higher wave numbers in PANI/CuS composite, which is attributed to the interaction of CuS nanoparticles with PANI chain. XRD pattern revealed the structurally ordered arrangement of polymer composite and this regularity increases with increase in concentration of nanoparticles. Glass transition temperature of the nanocomposite increased with increase in the concentration of nanoparticles and it indicated the ordered arrangement of the polymer composite than PANI. TGA studies indicated excellent thermal stability of polymer nanocomposite. The electrical properties of nanocomposites were studied from direct current and alternating current resistivity measurement. Conductivity, dielectric constant, and dissipation factor of the nanocomposite were significantly increased with the increase in CuS content in the nanocomposite. The enhancement of these properties suggests that the proposed PANI/CuS nanocomposites can be used as multifunctional materials for nanoelectronic devices. POLYM. ENG. SCI., 54:438–445, 2014. © 2013 Society of Plastics Engineers  相似文献   

5.
The TiO2 nanofibers and nanoparticles are prepared by electrospinning and molten salt method, respectively. The materials are characterized by X-ray diffraction scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and a thermal analysis. The SEM and TEM studies showed that fibers were of average diameter ∼100 nm and composed of nanocrystallites of size 10-20 nm. Electrochemical properties of the materials are evaluated using cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy. Cyclic voltammetric studies show a hysteresis (ΔV) between the cathodic and the anodic peak potentials for TiO2 nanofibers and nanoparticles (sizes ∼15-30 nm) are in the range, 0.23-0.30 V and a redox couple Ti4+/3+ around ∼1.74/2.0 V. Electrochemical cycling results revealed that the TiO2 nanofibers have lower capacity fading compared to that of the nanoparticles. The capacity fading for 2-50 cycles was ∼23% for nanofibers, which was nearly one-third of that of corresponding nanoparticles (∼63%). We discussed the effect of particle size on hysteresis and cycling performance of TiO2 nanoparticles. Impedance analysis of TiO2 nanofibers and nanoparticles during first discharge cycle is analyzed and interpreted.  相似文献   

6.
The photoluminescent germanium nanocrystals (Ge-NCs) were successfully incorporated into electrospun polymeric nanofiber matrix in order to develop photoluminescent nanofibrous composite web. In the first step, the synthesis of Ge-NCs was achieved by nanosecond pulsed laser ablation of bulk germanium wafer immersed in organic liquid. The size, the structural and the chemical characteristics of Ge-NCs investigated by TEM, XPS, XRD and Raman spectroscopy revealed that the Ge-NCs were highly pure and highly crystalline having spherical shape within 3–20 nm particle size distribution. In the second step, Ge-NCs were mixed with polyvinyl alcohol (PVA) polymer solution, and then, Ge-NC/PVA nanofibers were obtained via electrospinning technique. The electrospinning of Ge-NCs/PVA nanoweb composite structure was successful and bead-free Ge-NCs/PVA nanofibers having average fiber diameter of 185 ± 40 nm were obtained. The STEM analysis of the electrospun Ge-NCs/PVA nanofibers elucidated that the Ge-NCs were distributed homogeneously in the polymeric nanofiber matrix. The UV–Vis absorption and photoluminescence spectroscopy studies indicated the quantum confinement effect of Ge-NCs on the optical properties of the electrospun Ge-NCs/PVA nanoweb.  相似文献   

7.
A new type of mesoporous silica nanoparticle (MSN) was synthesized in fluoride media via sol–gel technique using TritonX 100 and Tween-20. The surface area and pore volume of the MSN particles were modified by varying the concentration of Tween-20. The prepared MSN nanoparticles with large surface area and pore volume (T-2, T-3) were selected to accommodate the model drug duloxetine hydrochloride (DX) for evaluation of their drug-loading and release abilities. Calcined and DX loaded nanoparticles were characterized by Brunauer–Emmett–Teller technique (BET), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG) analysis and UV-diffuse reflectance (UV-DRS). In vitro release studies proved that the particle displays an initial burst release followed by sustained release for up to 140 h. From the studies it is evident that the synthesized particle may be useful as a carrier for sustained release of active pharmaceutical ingredients (APIs).  相似文献   

8.
In this study, TiO2 nanofibers were fabricated via the electrospinning method followed by air annealing. Then, Ti-requirement in the conventional hydrothermal synthesis of BaTiO3 stoichiometry was supplied by using these nanofibers. The microstructural and compositional properties of BaTiO3 nanoparticles were studied using SEM, TEM, XRD, XPS, and Raman spectroscopy. The structural analysis showed that the cubic symmetry was the dominant one in the BaTiO3 nanoparticles, whereas Raman spectroscopy indicated the coexistence of cubic symmetry with the tetragonal polymorph. The nanoparticles displayed higher photocatalytic reactivity under UV-A light compared to visible irradiation during decomposition of methylene blue dye and reached 24.2% and 18.8% degradation, respectively, after 1 hour. Furthermore, the dielectric properties were investigated using sintered compacts of these nanoparticles. Among the employed temperatures for sintering, the highest relative density (90%) and dielectric constant (2165 at 1 MHz) were obtained at 1250°C and 5 hours. This study revealed that the electrospun TiO2 nanofiber precursor can successfully be used for the production of nanoscale barium titanate particles suitable for various applications.  相似文献   

9.
Silver/polyaniline (Ag-PANi) nanocomposites were prepared via in situ reduction of silver in aniline by mild photolysis performed with short wavelength (365 nm) radiation from UV lamp for 12 h. Reduction of the silver in aqueous aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of aniline into polyaniline. A slightly broadened X-ray diffraction (XRD) pattern suggests small particle which was size consistent with cubic silver nanoparticles. The UV–Vis absorption revealed that the bands at about 400–420 nm due to benzonoid ring of the polyaniline are overlapped and blue-shifted due to the presence of silver nanoparticles in powdered state. Scanning electron microscopy (SEM) of the silver/polyaniline (Ag-PANi) nanocomposite showed a size distribution with nanofibers and granular morphology of silver nanoparticles. Our findings are not only the promising approach for electro-catalytic hydrazine oxidation but also utilized in the other bio-sensing applications.  相似文献   

10.
A nanofiber membrane composed of poly(ε‐caprolactone) (PCL), poly(vinyl pyrrolidone) (PVP), and silver nanoparticles was prepared via electrospinning technique. The morphology and structure of the PCL/PVP/Ag nanofibers composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). The SEM images showed that various composites of PCL/PVP/Ag could be electrospun to yield continuous and uniform nanofibers. FTIR spectra indicated that the molecular interactions between PCL and PVP are weak. The hydrophilicity, mechanical property, and swelling behavior of the as‐spun composites can be manipulated by altering the blend ratio of PCL/PVP. XRD patterns and XPS spectra showed that the Ag nanoparticles were dispersed in the PCL/PVP nanofiber composites; and the Ag nanoparticles endowed the PCL/PVP/Ag composite with antibacterial activities. The obtained PCL/PVP/Ag nanofiber composites with the morphology similar to that of native extracellular matrix have the potential to create a moist environment and to kill bacteria, which make it possible to be used for wound dressing application. POLYM. COMPOS., 37:2847–2854, 2016. © 2015 Society of Plastics Engineers  相似文献   

11.
The main aim of this study is to investigate the effect of silver‐doped zinc oxide (Ag‐ZnO) loading on the structural, morphological, thermal and electrical properties, and gas sensing behavior of polypyrrole (PPy)/phenothiazine (PTZ)‐blend nanocomposites. The composites are characterized by FTIR, XRD, SEM, TEM, DSC, TGA, and impedance studies. FTIR spectra exhibit the presence of Ag‐ZnO in the PPy/PTZ blend. XRD analysis shows that the semicrystalline behavior of the polymer blend is greatly enhanced by the addition of Ag‐doped ZnO particles. Uniform dispersion of nanoparticles in the polymer is obtained from SEM analysis. The TEM images confirm the presence of spherically shaped nanoparticles in PPy/PTZ blend with a size of 10–25 nm. The DSC measurement indicates that the glass transition temperature of PPy/PTZ blend was significantly improved in the presence of Ag‐doped ZnO nanoparticles. The thermal decomposition temperature of nanocomposite obtained from TGA shows an increase with increase in the content of Ag‐ZnO particles. The incorporation of Ag‐doped ZnO nanoparticles to PPy/PTZ blend exhibit increase in the AC conductivity and dielectric properties of the nanocomposite, due to the pilling of charges at the extended interface of the composite system. The DC conductivity of the nanocomposite increases with the loading of nanoparticles. The ammonia gas sensing performance of PPy/PTZ/Ag‐ZnO nanocomposite is analyzed, and the result shows that the fabricated blend composite can be used as a promising candidate for the easy access of gas molecules. J. VINYL ADDIT. TECHNOL., 26:187–195, 2020. © 2019 The Authors. Journal of Vinyl and Additive Technology published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.  相似文献   

12.
Chitosan (CS) nanofibers were successfully used to modify indium tin oxide (ITO) electrode by electrospinning technique. Then, Prussian blue (PB) nanoparticles were electrodeposited on the CS nanofibers by potentiostatic technique in an acidic solution containing single ferricyanide. By this method, direct synthesis of PB nanoparticles on the nanofibers that were used for modifying electrode came true. Transmission electronic microscopy (TEM) showed that the average size of PB nanoparticles was about 50 nm. Selected-area electron diffraction (SAED) showed diffusive diffraction spots, indicating the mosaic structure of the PB nanoparticles on the CS nanofibers. X-ray powder diffraction (XRD) displayed the long-range disorder of CS nanofibers and demonstrated the formation of PB nanoparticles. Results of the scanning electron microscope (SEM) images indicated that the PB nanoparticles could be electrodeposited on the CS nanofibers. The amount of the PB nanoparticles on the CS nanofibers increased with increasing potential value of the electrodeposition. In addition, the cyclic voltammetric response displayed two characteristic redox couples of PB. The modified electrode exhibited electrocatalytic activity towards reduction of H2O2.  相似文献   

13.
《Ceramics International》2017,43(10):7682-7689
Herein, we report a sustainable production of magnetic cobalt ferrite nanoparticles by conventional (CHM) and microwave heating (MHM) method. Hibiscus rosa-sinensis extract was used as both reducing and stabilizing agent. Using plant extracts to synthesize nanoparticles has been considered as an eco-friendly method, since it avoids noxious chemicals. The plethora of plant extract mediated nanoparticles were compared by techniques, such as XRD, Rietveld, FT-IR, SEM, EDX, UV-Visible DRS, PL and VSM were carried out to analyze and understand their crystallite size, functional groups, morphology, optical and magnetic properties. The crystalline structure of cobalt ferrite nanoparticles revealed the cubic structure and the microwave heating of nanoparticles showed smaller crystallite size compared to the conventional heating, which was then confirmed by XRD analysis. To analyze the presence of functional groups and the phytochemical involvement of the plant extract was confirmed by FT-IR studies. Spherical morphology with less than 100 nm sized particles was confirmed by SEM and EDX analysis confirm the existence of Co, O, and Fe elements present in the samples. UV-Visible DRS studies were carried out to calculate the band gap of the as-synthesized nanoparticles, estimated from the Kubelka-Munk function, as 2.06, and 1.87 eV for CHM and MHM, respectively. Photoluminescence emission spectrum of the nanoparticles showed two different bands at 494 and 620 nm, which explores the optical properties of the nanoparticles, due to the quantum confinement effect. VSM analysis showed better ferromagnetic behavior, which can be used for magnetic applications.  相似文献   

14.
《Ceramics International》2023,49(8):12231-12239
Ultra-rapid microwave-assisted hydrothermal synthesis was performed, zinc oxide nanoparticles were fabricated and doped with gallium. Different times (5, 15, and 30 min) and concentrations of doped Ga (1, 3, and 6%) were used to improve their characteristic properties. In addition, the relation between time/dopant was analyzed. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Photoluminescence (PL) to verify number of defects. SEM analysis showed the formation of nanorods morphology even with a short synthesis time. The X-ray diffractograms and Raman spectra suggest the successful insertion of Ga into the ZnO lattice. The crystallite size obtained by doping was between 36 and 50 nm. The lattice parameters determined by the Rietveld refinement confirmed the formation of a wurtzite hexagonal structure. The band gap range found was 3.12–3.22 eV, which increases the potential of ZnO for optical applications. The presence of defects as result of doping was confirmed by PL. The microstructural changes of the material are enhanced by doping, which causes the photocurrent to increase from 0,002 to 0.012 mA/cm2 in doped ZnO. The synthesis time and Ga doping facilitated the production of ZnO nanoparticles with improved properties.  相似文献   

15.
《Ceramics International》2015,41(7):8382-8387
As a part of the desire to save the environment via green chemistry practices, we report a novel method to synthesize ZnO nanoparticles from nontoxic and biocompatible chemicals where no pollutant or combustible side product is produced. In this recipe, a binary Zn(II) Schiff-base complex is obtained from alanine where water is used as solvent and a biologically compatible amino acid instead of toxic amines is used as a nitrogen source. The Schiff-base complex is subsequently heat treated to synthesize ZnO particles via a solid-state decomposition process. The effect of post heat treatment temperature (400, 500, and 600 °C) on microstructure and defect content of ZnO nanoparticles is investigated. The formation of single phase ZnO particles is confirmed by XRD θ–2θ patterns and FTIR spectra. TEM and SEM micrographs indicate the formation of nanoparticles with a particle size of 50–110 nm for different heat treatment temperatures. Combing XRD, FTIR, and PL results, it is revealed that the samples heat treated at intermediate temperatures (500 °C) possess the lowest defect concentration and a favorable crystallinity. This study emphasizes on green chemistry and synthesis of nanomaterials through ecofriendly methods to save our planet and its reservoirs for future and next generations.  相似文献   

16.
The electrospun nanofibers emerge several advantages because of extremely high specific surface area and small pore size. This work studies the effect of PVA nanofibers diameter and nano‐sized TiO2 on optical properties as reflectivity of light and color of a nanostructure assembly consisting polyvinyl alcohol and titanium dioxide (PVA/TiO2) composite nanofibers prepared by electrospinning technique. The PVA/TiO2 composite spinning solution was prepared through incorporation of TiO2 nanoparticles as inorganic optical filler in polyvinyl alcohol (PVA) solution as an organic substrate using the ultrasonication method. The morphological and optical properties of collected composites nanofibers were highlighted using scanning electron microscopy (SEM) and reflective spectrophotometer (RS). The reflectance spectra indicated the less reflectance and lightness of composite with higher nanofiber diameter. Also, the reflectance and lightness of nanofibers decreased with increasing nano‐TiO2 concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
The polymeric blend was fabricated with crystalline poly(vinylidene fluoride) (PVDF)/amorphous functionalized-poly(methyl methacrylate) (PMMA) in 70/30 w/w ratio by chemical mixing method. Functionalization of PMMA was achieved with 2-amino-5-nitrobenzoic acid. The prepared polymer blend was used as a matrix to synthesize nanocomposites with undoped/doped zinc oxide (ZnO) nanoparticles. Doping in ZnO was achieved with vanadium, sulfur, and dysprosium elements as a dopant. The structural, optical, electronic, and morphological properties of undoped/doped nanosized ZnO and blended nanocomposites were accessed through sophisticated analytical techniques, that is, Fourier transform infrared (FTIR), ultraviolet–visible (UV–vis), UV–vis–diffuse reflectance spectra, nuclear magnetic resonance, fluorescence spectroscopy, X-ray diffraction (XRD), transmission electron microscopy, and scanning electron microscopy. The FTIR band at 1165–1176 cm−1 in functionalized-PMMA indicate the formation of aliphatic C-N bond along with aromatic 1H chemical shift (δ) at 7.134, 7.829 and 8.210 ppm confirm the successfully functionalization of PMMA. The prominent XRD peak at 2θ = 20.8° in nanocomposites shown improvement in β-phase of PVDF. The results show that Dy doped ZnO nanoparticles create remarkable effect on various properties of nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47116.  相似文献   

18.
The effect of blend composition on the morphology, dynamic mechanical properties, thermal and physico-mechanical properties of linear low density polyethylene (LLDPE)/ ethylene-co-methyl acrylate (EMA) blends were studied. The blend showed both dispersed and continuous phase morphology that depends on the blend composition. A co-continuous structure is formed for blends containing 50 wt% of EMA. Dynamic mechanical studies showed that flexibility of the blend enhanced with the expansion of the amorphous region as EMA content increased. However, two separate melting temperature peak observed in differential scanning calorimetry (DSC) analysis indicate that the blends are immiscible in crystalline region of the two polymers. X-ray diffraction (XRD) studies showed that crystallinity of blends decreases with increase in EMA content and negative deviation of tensile strength from the mixing rule indicates the poor interfacial adhesion between the two components. FTIR spectroscopy established the lack of chemical interaction between LLDPE and EMA, which support the SEM, DSC, DMA and XRD observations. Parallel-Voids model has been applied to characterize phase morphology of these blends.  相似文献   

19.
《Ceramics International》2022,48(4):4874-4885
The effects of lemon juice and annealing treatment on phase composition, vibrational modes, microstructural and dielectric behavior of Mg doped copper ferrite nanoparticles have been synthesized and analyzed in detail in this present work. The various characterization techniques are used to examine the phase, microstructural, vibrational and dielectric nature of the samples at different annealing temperatures (600 °C and 900 °C). The phase and microstructure of Mg substituted CuFe2O4 nanoparticles have been analyzed by XRD, SEM and TEM. The secondary phase peaks free XRD spectra revealed that the as burst and the annealed Mg–CuFe2O4 nanoparticles have single phase cubic spinel structure. The average crystallite size of the as burnt, annealed 600 °C and annealed 900 °C of as prepared nanoparticles are calculated as 8.9 nm, 12.8 nm and 31.6 nm respectively. Another verification of the spherical shaped particle's size was confirmed by TEM analysis and it found as average size of 28.7 nm, this result is well matched with XRD analysis. The effect of size with impact of annealing treatment on magnetic and dielectric properties also analyzed. The size-dependent Mg–CuFe2O4 nanostructures exhibit promising sensing properties which ensure them as a potential candidate for humidity sensor applications. The as-burnt and annealed samples both show a humidity response over the humid range of 10–95 %RH. The sample annealed at 900 °C has the highest average sensor response (6.02 MΩ/%RH) among the as-burnt sample (6.38 MΩ/%RH) and annealed sample at 600 °C (7.11 MΩ/%RH).  相似文献   

20.
Blends of low‐density polyethylene (LDPE) and a glass‐filled thermotropic liquid crystalline polymer (LCP‐g) have been prepared by melt mixing techniques. The thermal transitions, dynamic behavior, morphology and crystalline properties of the blends have been measured by DSC, DMTA, SEM and XRD respectively. The crystallinity decreased with increase in LCP‐g content in the blends. At higher levels of LCP‐g, crystal growth is favored in the PE phase. From DSC, it is found that the thermal stability of the blends increased with the LCP‐g content. The variation of storage modulus, loss modulus and stiffness as a function of blend ratio suggested the phase inversion at the 40–50% level of LCP‐g in the blend. SEM studies revealed that with the increase in LCP‐g content, the flow of the matrix was restricted.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号