<正>The stability ofpoly(vinyl alcohol)(PVA) nanofibrous mats in water media was improved by post-electrospinning treatments.Bifunctional glutaraldehyde(GA) in methanol was used as a crosslinking agent to stabilize PVA nanofiber,but fiber twinning was observed frequently,and the highly porous structure of PVA nanofibrous mats was destroyed when the crosslinked fiber was soaked in water.To overcome this shortcoming,chitosan(CS) was introduced into the PVA spinning solution to prepare PVA/CS composite nanofibers.Their treatment in GA/methanol solution could retain the fiber morphology of PVA/CS nanofibers and porous structure of PVA/CS nanofibrous mats even if they were soaked in aqueous solutions for 1 month.Scanning electron microscopy(SEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC) were applied to characterize the physicochemical structure and thermal properties of PVA nanofibers.It was found that the water resistance of PVA nanofibrous mats was enhanced because of the improvement of the degree of crosslinking and crystallinity in the electrospun PVA fibers after soaking in GA/methanol solution. 相似文献
Fairly uniform chitosan (CS)/poly(ethylene oxide) (PEO) ultrafine fibers containing silver nanoparticles (AgNPs) were successfully
prepared by electrospinning of CS/PEO solutions containing Ag/CS colloids by means of in situ chemical reduction of Ag ions.
The presence of AgNPs in the electrospun ultrafine fibers was confirmed by X-ray diffraction patterns. The AgNPs were evenly
distributed in CS/PEO ultrafine fibers with the size less than 5 nm observed under a transmission electron microscope. X-ray
photoelectron spectroscopy suggested that the existence of Ag―O bond in the composite ultrafine fibers led to the tight combination
between Ag and CS. Evaluation of antimicrobial activities of the electrospun Ag/CS/PEO fibrous membranes against Escherichia coli showed that the AgNPs in the ultrafine fibers significantly enhanced the inactivation of bacteria. 相似文献
Summary: Electrically conducting polypyrrole‐poly(ethylene oxide) (PPy‐PEO) composite nanofibers are fabricated via a two‐step process. First, FeCl3‐containing PEO nanofibers are produced by electrospinning. Second, the PEO‐FeCl3 electrospun fibers are exposed to pyrrole vapor for the synthesis of polypyrrole. The vapor phase polymerization occurs through the diffusion of pyrrole monomer into the nanofibers. The collected non‐woven fiber mat is composed of 96 ± 30 nm diameter PPy‐PEO nanofibers. FT‐IR, XPS, and conductivity measurements confirm polypyrrole synthesis in the nanofiber.
An SEM image of the PPy‐PEO composite nanofibers. The scale bar in the image is 500 nm. 相似文献
The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were fabricated by one-step electrospinning and ion-imprinting methods and their application as adsorbents for metal ions was also investigated.The resulting chitosan nanofiber mats were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and thermal gravimetric analysis(TGA).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were used as adsorbents for the removal of Pb(Ⅱ)ions from aqueous or acid solutions.The effects of p H values,contact time,content of crosslinker(glutaraldehyde)on Pb(Ⅱ)ions adsorption were studied.The results indicated that the Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had the highest adsorption capacity of 110.0 mg/g at p H 7.The kinetic study demonstrated that the adsorption of Pb(Ⅱ)ions followed the pseudo-second-order model.The equilibrium isotherm data showed that the Langmuir model was the most suitable for predicting the adsorption isotherm of the studied system.The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had good adsorption selectivity,which illustrates the equilibrium adsorption capacity in the order of Pb(Ⅱ)Cu(Ⅱ)Zn(Ⅱ)Cd(Ⅱ)Ni(Ⅱ).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were stable and had good reuse ability. 相似文献
Chitosan–poly(vinyl alcohol), CS–PVA, blended membranes were prepared by solution casting of varying proportions of CS and PVA. The blend membranes were then crosslinked interfacially with trimesoyl chloride (TMC)/hexane. The physiochemical properties of the blend membranes were determined using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), tensile test and contact angle measurements. Results from ATR-FTIR show that TMC has crosslinked the blend membranes successfully, and results of XRD and DSC show a corresponding decrease in crystallinity and increase in melting point, respectively. The crosslinked CS–PVA blend membranes also show improved mechanical strength but lower flexibility in tensile testing as compared to uncrosslinked membranes. Contact angle results show that crosslinking has decreased the surface hydrophilicity of the blend membranes. The blend membrane properties, including contact angle, melting point and tensile strength, change with a variation in the blending ratio. They appear to reach a maximum when the CS content is at 75 wt%. In general, the crosslinked blend membranes show excellent stability during the pervaporation (PV) dehydration of ethylene glycol–water mixtures (10–90 wt% EG) at different temperatures (25–70 °C). At 70 °C, for 90 wt% EG in the feed mixture, the crosslinked blend membrane with 75 wt% CS shows the highest total flux of 0.46 kg/(m2 h) and best selectivity of 986. The blending ratio of 75 wt% CS is recommended as the optimized ratio in the preparation of CS–PVA blend membranes for pervaporation dehydration of ethylene glycol. 相似文献
Fabrication of electrospun chitosan nanofibers is still a controversial issue in publications. Although regarding the lots of reports, mixtures of chitosan with a hydrophilic synthetic polymer such as polyethylene oxide (PEO) have been electrospun successfully, abundance of partly contradictory protocols in which one variable has been surveyed in each study is unfortunately baffling. In the present study, influence of three considerable parameters including the average molecular weight of chitosan, chitosan solution concentration and the mass ratio of polyethylene oxide to chitosan at the mixtures on electrospinning possibility as well as the quality of as-spun fibers is investigated. Eventually, the necessities for obtaining the best results are introduced followed by further analysis of optimized nanofibers using atomic force microscopy. According to our results, the blend solutions prepared from the low molecular weight (LMW) chitosan and PEO are efficient for reproducible production of bead-free electrospun nanofibers even in low proportion of polyethylene oxide. 相似文献
Collagen functionalized thermoplastic polyurethane nanofibers (TPU/collagen) were successfully produced by coaxial electrospinning technique with a goal to develop biomedical scaffold. A series of tests were conducted to characterize the compound nanofiber and its membrane in this study. Surface morphology and interior structure of the ultrafine fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), whereas the fiber diameter distribution was also measured. The crosslinked membranes were also characterized by SEM. Porosities of different kinds of electrospun mats were determined. The surface chemistry and chemical composition of collagen/TPU coaxial nanofibrous membranes were verified by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometry (FTIR). Mechanical measurements were carried out by applying tensile test loads to samples which were prepared from electrospun ultra fine non-woven fiber mats. The coaxial electrospun nanofibers were further investigated as a promising scaffold for PIECs culture. The results demonstrated that coaxial electrospun composite nanofibers had the characters of native extracellular matrix and may be used effectively as an alternative material for tissue engineering and functional biomaterials. 相似文献
Three different solvent mixtures were used to prepare electrospun membranes based on polylactic acid (PLA), polyethylene oxide (PEO) and enzymatic cellulose nanofibers (CNF). The materials were characterized from a morphological, spectroscopic, mechanical and rheological point of view. Furthermore, swelling test were performed in order to assess the water uptake of each sample.The results put into evidence that the choice of the solvents affects the structure and the properties of the membranes. Among the protocols tested, using chloroform/acetone/ethanol mixture was found to allow a high degree of CNF dispersion and a good electrospinnability of polymer solutions. These features led to membranes with impressive improvement of mechanical properties (+350% in stiffness, +350% in tensile strength and +500% in toughness) with respect to those of PLA/PEO and dramatically increased the water uptake of these materials (up to +350% within 120 min). 相似文献
Convenient and integration fabrication process is a key issue for the application of functional nanofibers. A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV) protection nanofibers. The titanium dioxide(TiO2) nanoparticles suspension was delivered through the shell channel of the coaxial spinneret, by which the aggregation of TiO2 nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO) nanofiber was obtained. With the content of TiO2 increasing from 0 to 3%(mass fraction), the average diameter of nanofibers increased from (380±30) nm to (480±100) nm. The surface functionalization can be realized during the electrospinning process to gain PEO/TiO2 composite nanofibers directly. The uniform distribution of TiO2 nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance. The maximum UV protection factor(UPF) value of composite nanofibers reaches 2751. This work presented a novel surface-functionalized way for the preparation of composite nanofiber, which has great application potential in the field of micro/nano system integration fabrication. 相似文献
By means of the electrospinning technique we have successfully synthesized cyclodextrin (CD) functionalized polyethylene oxide (PEO) nanofibers (PEO/CD) with the ultimate goal to develop functional nanowebs. Three different types of CDs; α-CD, β-CD and γ-CD are incorporated individually in electrospun PEO nanofibers. The aqueous solutions containing different amount of PEO (3%, 3.5% and 4% (w/v), with respect to solvent) and CDs (25% and 50% (w/w), with respect to PEO) are electrospun and bead-free nanofibers are obtained. The presence of the CDs in the PEO solutions is found to facilitate the electrospinning of bead-free nanofibers from the lower polymer concentrations and this behavior is attributed to the high conductivity and viscosity of the PEO/CD solutions. The presence of CDs in the electrospun PEO nanofibers is confirmed by Fourier transform infrared (FTIR) spectroscopy studies. The 2-D X-ray diffraction (XRD) spectra of PEO/CD nanowebs did not show any significant diffraction peaks for CDs indicating that the CD molecules are distributed within the polymer matrix without any phase separated crystalline aggregates. 相似文献
Water holding capacity becomes essential for hygiene applications including baby diapers. Microfibers of hydrophilic polymers have been useful source for such applications. While, super hydrophilic and stable nanofibers incorporation with functional antibacterial agent are essential to get higher absorption of water along with antimicrobial activity against harmful bacteria. In current work, hydrophobic polymeric nanofibers are transformed to super hydrophilic nanofibers by addition of copper (II) oxide (CuO hereafter) nanoparticles. CuO nanoparticles provided two distinctive properties to existing nanofibers. Firstly, nanofibers surface area was significantly increased, and secondly copper (II) oxide itself is hydrophilic material which imparted hydrophilicity to base polymer. Polyacrylonitrile, crosslinked Polyvinyl Alcohol, and PICT were selected as super hydrophobic polymeric nanofibers. Copper II oxide nanoparticles (same concentration) were added in all polymer solution and electrospun. Surface, morphological, and hydrophilic properties were characterized and it was concluded that copper II oxide is suitable for transforming hydrophobic nanofibers to super hydrophilic nanofibers. Water holding capacity (WHC) was also improved for all prepared nanofiber mats. WHC for PVA/CuO, PAN/CuO, and PICT/CuO were recorded an average of 23 g/g, 21 g/g, and 18 g/g respectively. Combining all useful results from possible characterization of nanofiber mats, it is expected that CuO nanoparticles loaded nanofibers will have potential application as antibacterial, sustainable, and stable replacement of hygiene products. 相似文献
This review aims to provide a literature overview as well as the authors’ personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemical properties. To the readers’ convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap-platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets-PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non-toxic, non-yellowing, and non-inflammable. Medical applications of Lap/PEO composites in bio-sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed. 相似文献
The present study describes the harnessing of revalued cow milk (denoted as waste milk) for fabricating casein fibers (CAS) with enhanced mechanical performance and antibacterial properties by the electrospinning method. For this purpose, polyethylene oxide (PEO) was employed (10 and 20 wt%) as a binder for the appropriate electrospun CAS fibers. Different amount of tannic acid (TA) was incorporated into casein/polyethylene oxide fibers (CAS/PEO) as a crosslinker agent, bringing filaments with a diameter of ca. 2 µm. The incorporation of 4 wt% of TA promotes the fibers' reticulation, forming a stable three-dimensional network. Also, the mechanical performance of CAS/PEO fibers was improved, where the tensile strength was increased from 0.91 MPa to 1.88 MPa with 4 % of TA, while the breaking elongation was increased from 93.74 % to 274.56 %. This behavior benefits the processing of fibers by electrospinning. Furthermore, the TA addition during the electrospun of CAS/PEO fibers enhances fibers' wettability properties and thermal stability induced by the crosslinker agent. Additionally, the antibacterial activity (AA) test demonstrates that CAS fibers can inhibit the growth of Gram-positive S. aureus and Gram-negative E. coli after 0.5 h, 1.5 h, 3 h, and 24 h of contact, which is generated by the TA addition. Our results suggest that the electrospun fabrication of CAS/PEO fibers with TA as a crosslinker agent represents an innovative harnessing of waste milk to produce functional textiles with potential biological application. 相似文献
Simvastatin (SIM) particles are liposoluble drugs with large particle sizes, resulting in poor compatibility with electrospun polycaprolactone (PCL)/polyethylene glycol (PEG) nanofibers, so that part of them will be exposed to the electrospun nanofiber surface, which is easy to cause the burst release of drugs. Therefore, in this paper, stearic acid (SA) with good biocompatibility was innovatively added to increase the dispersion uniformity of SIM in the spinning solution, thus improving the performances of SIM-loaded PCL/PEG nanofiber membranes (NFMs). Accordingly, the effects of SA addition on the morphologies, mechanical properties, wettability, and drug release properties of the SIM-loaded NFMs were studied. The results showed that after SIM was dissolved in SA solution, the particle size of SIM was significantly reduced and could be evenly dispersed in the polymer spinning solution, thus obtaining the SIM-loaded composite NFMs with the best morphology and performance. 相似文献
In this study, polystyrene nanofibers were prepared by electrospinning for the adsorption of olanzapine, risperidone, and clozapine from aqueous solution. The properties of polystyrene nanofibers were characterized via FTIR, SEM, TEM, TG, and XRD analyses. In addition, the impact of contact time, initial ion concentration, adsorbent dosage, temperature, and pH on the adsorption was studied. The adsorption kinetics and thermodynamic evaluation of three analytes on PS nanofibers were performed. The adsorption of the three analytes by polystyrene nanofibers followed the first-order kinetics with constant rates of 0.02348, 0.02683, and 0.03024 mg/g min for olanzapine, risperidone, and clozapine, respectively. Further, the adsorption conformed to Redlich-Peterson isotherm model and the maximum adsorption capacities for olanzapine, risperidone, and clozapine were 12.33, 8.36, and 12.96 mg/g, respectively. The adsorption process was characterized by spontaneous, exothermic, and physical reaction. The regeneration of nanofiber adsorbent showed that the adsorption capacity did not significantly change after 5 cycles of desorption. The selectivity of different analytes followed the order of clozapine > risperidone > olanzapine. Thus, the polystyrene electrospun nanofibers exhibit good potential as novel adsorbents for the isolation and purification of antipsychotic drugs from biological samples. 相似文献
ZnO nanofibers were prepared from zinc acetate/polyvinyl alcohol (PVA) by electrospun method. The morphological features,
crystallinity, mechanical and optical properties of the ZnO nanofibers were studied. The results show the specific surface
area of the ZnO nanofibers was influenced by the electrospun conditions. The specific surface area reached 389.7 m2g−1 as the average diameter was 232 nm. The XRD date reveals the nanofibers consist of a single phase of well-crystallized ZnO
with hexagonal structure. The elastic modulus of a single ZnO nanofiber was also characterized by nano-scale three-point bending
test. 相似文献
In recent decades, the number of patients requiring biocompatible and resistant implants that differ from conventional alternatives dramatically increased. Among the most promising are the nanocomposites of biopolymers and nanomaterials, which pretend to combine the biocompatibility of biopolymers with the resistance of nanomaterials. However, few studies have focused on the in vivo study of the biocompatibility of these materials. The electrospinning process is a technique that produces continuous fibers through the action of an electric field imposed on a polymer solution. However, to date, there are no reports of chitosan (CS) and polyvinyl alcohol (PVA) electrospinning with carbon nano-onions (CNO) for in vivo implantations, which could generate a resistant and biocompatible material. In this work, we describe the synthesis by the electrospinning method of four different nanofibrous membranes of chitosan (CS)/(PVA)/oxidized carbon nano-onions (ox-CNO) and the subdermal implantations after 90 days in Wistar rats. The results of the morphology studies demonstrated that the electrospun nanofibers were continuous with narrow diameters (between 102.1 nm ± 12.9 nm and 147.8 nm ± 29.4 nm). The CS amount added was critical for the diameters used and the successful electrospinning procedure, while the ox-CNO amount did not affect the process. The crystallinity index was increased with the ox-CNO introduction (from 0.85% to 12.5%), demonstrating the reinforcing effect of the nanomaterial. Thermal degradation analysis also exhibited reinforcement effects according to the DSC and TGA analysis, with the higher ox-CNO content. The biocompatibility of the nanofibers was comparable with the porcine collagen, as evidenced by the subdermal implantations in biological models. In summary, all the nanofibers were reabsorbed without a severe immune response, indicating the usefulness of the electrospun nanocomposites in biomedical applications. 相似文献
In this communication, biodegradable and highly elastic silk fibroin/poly(lactide-co-ε-caprolactone)/polyethylene oxide (SF/PLCL/PEO) tri-polymers composite film was fabricated by sol–gel casting technology. The tri-polymers composite film exhibited a high cycle performance and rapid degradation rate by regulating the content of blending of the three polymer contents. The viability of cardiomyocyte cells was demonstrated for both SF/PLCL and SF/PLCL/PEO composite films after 1 day of culture, although the tri-polymers composite film demonstrated superior cell growth, attachment and spreading after culturing for 7 days. Study findings support the potential application of this biocompatible tri-polymers composite film as a heart patch substitute with multi-functionalities. 相似文献