Cyclodextrins (CD) are cyclic oligosaccharides that can form noncovalent host–guest inclusion complexes to yield intriguing supramolecular structures. Electrospinning of nanofibers from CD is challenging since they are small molecules, nonetheless, electrospun nanofibers from CD would be particularly attractive because of the distinctive properties obtained by combining the very large surface area of nanofibers along with the inclusion complexation capability of CD. Herein, we performed the electrospinning of native CD type (i.e. γ-CD) using a minimal amount of carrier polymeric matrix (polyethylene oxide (PEO)). Once, the uniform nanofibers were electrospun from γ-CD/PEO systems, the polymeric carrier matrix was selectively removed by simple washing procedure, at the end, γ-CD short-nanofibers were obtained. We observed that γ-CD short-nanofibers could remove volatile organic compounds (VOC) (i.e. aniline) due to the inclusion complexation capability whereas pristine γ-CD powder could not have the capability for the VOC removal. 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
The electrospinning of polymer-free nanofibers from highly concentrated (160%, w/v) aqueous solutions of hydroxypropyl-β-cyclodextrin (HPβCD) and its inclusion complexes with triclosan (HPβCD/triclosan-IC) was achieved successfully. The dynamic light scattering (DLS) and rheology measurements indicated that the presence of considerable HPβCD aggregates and the high solution viscosity were the key factors in obtaining electrospun HPβCD and HPβCD/triclosan-IC nanofibers without the use of any polymeric carrier. The HPβCD and HPβCD/triclosan-IC solutions containing 20% (w/w) urea yielded no fibers but only beads and splashes because of the depression of the self-aggregation of the HPβCD. The inclusion complexation of triclosan with HPβCD was studied by isothermal titration calorimetry (ITC) and turbidity measurements. The characteristics of the HPβCD and HPβCD/triclosan-IC nanofibers were investigated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). It was found that the electrospinning of HPβCD/triclosan-IC solution having a 1:1 molar ratio was optimal for obtaining nanofibers without any uncomplexed guest molecules. 相似文献
The electrospinning process was used successfully to embed single-walled carbon nanotubes (SWCNTs) in a poly(ethylene oxide) (PEO) matrix, forming composite nanofibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphiphilic alternating copolymer of styrene and sodium maleate. The resulting dispersions were stable, having a dark, smooth, ink-like appearance. For electrospinning, the dispersions were mixed with PEO solution in an ethanol/water mixture. The distribution and conformation of the nanotubes in the nanofibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nanotubes within the nanofibers to facilitate direct observation. Nanotube alignment within the nanofibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nanotubes were embedded in a straight and aligned form, while entangled nonseparated nanotubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electrospun nanofibers with embedded SWCNTs. This result is in pronounced distinction to the detrimental effect of incorporation of multiwalled carbon nanotubes on polymer orientation in electrospun nanofibers, as reported previously. 相似文献
Chitosan/poly(ethylene oxide) (PEO) (5:1) nanofibers with cellulose nanocrystals (CNCs) were produced using an electrospinning technique. The addition of CNCs to the chitosan/PEO solutions allowed the production of uniform fibers (without beads) with a high proportion of chitosan. The fiber diameters were influenced by the concentration of CNCs in the chitosan/PEO solutions. The solutions containing 10% (w/w) of CNCs produced thinner fibers compared to solutions containing 5% (w/w) of CNCs. Thermogravimetric analysis indicated that the nanofibers were thermally stable, despite the CNCs having an effect on the PEO decomposition. Results from the cell assay in cultures of 3T3 fibroblasts indicated that the chitosan/PEO nanofibers (with 10% CNCs) promoted cell attachment with changes in the cytoskeletal organization. The results obtained in this work highlight the favorable effect of CNCs in electrospinning of chitosan/PEO. As expected, the influence of nanofibers on 3T3 fibroblasts F-actin and β-tubulin network revealed alterations in cytoskeleton, leading to changes in cell morphology and spreading. 相似文献
New nanofibers containing poly(vinyl pyrrolidone)-iodine complex (PVP-iodine) were obtained by electrospinning in order to prepare materials suitable for wound dressings. Different approaches were used: a one-step method based on electrospinning of PVP-iodine or poly(ethylene oxide)/PVP-iodine solutions and a three-step method based on electrospinning of PVP or poly(ethylene oxide)/PVP mixed solutions followed by photo-mediated crosslinking of the obtained nanofibers and subsequent complexation with iodine. The average diameters of the fibers were in the range 150-470 nm depending on the composition and on the applied field strength (AFS) and increased with increasing the amount of PEO in the spinning solutions. Higher AFS resulted in greater fiber diameter and in size distribution broadening. Photo-mediated crosslinking in the presence of 4,4′-diazidostilbene-2,2′-disulfonic acid disodium salt successfully stabilized the electrospun PVP and PEO/PVP nanofibers against water and water vapor. 相似文献
Ag nanoparticle-embedded one-dimensional β-CD (β-cyclodextrin)/PVP composite nanofibers were prepared using a one-step electrospinning
technique. Ag nanoparticles were obtained in the AgNO3/β-CD/DMF solution, in which silver nitrate been introduced as the precursor, DMF as solvent, β-CD as reducing and capping
agent. After electrospinning of the composite solution at room temperature, the β-CD/PVP nanofibers containing Ag nanoparticles
were obtained. The electrospun composite solution containning Ag nsnopsrticles were confirmed by UV-visible absorption spectra;
the resulting composite nanofibers were characterized by scanning electron microscopy , transmission electron microscopy,
and X-ray diffraction. Ag-β-CD/PVP nanofiber exhibits good antibacterial property for Escherichia coli and Staphylococcus aureus. Consequently, we propose that these Ag nanoparticle-embedded 1D-nanostructures prepared via electrospinning may be used
as antibacterial material. 相似文献
It is difficult to produce rubbery polymer nanofibers, that is, polybutadiene, by the method of electrospinning, since during electrospinning rubbery polymer fibers join and entangles due to their low Tg. For this reason, it is not easy to achieve the fiber form out of these polymers. Homogeneously electrospun carbon nanotubes (CNT)‐filled polybutadiene (PBu) and poly(ethylene oxide) (PEO) composite elastomeric fibers exhibit distinctive physical features such as uniform fiber diameter and distribution with significant improvements in thermomechanical properties. Controlled hydrophilicity/hydrophobicity with the components allows to generate homogenous, thermally stable and stretchable bio‐composite scaffold, and fibrous antibacterial membrane scaffolds out of PBu/PEO/CNT composite. We have combined the exciting properties of PEO with high pore density with the rubber elasticity of PBu via dissolving them in a dichloromethane/ethyl acetate organic solvent, and subsequently producing electrospun woven fibers with different PBu/PEO ratios. Frequency‐dependent thermomechanical characterization via dynamic mechanical analysis reveals pronounced changes in the onset and extent of melting, as well as the storage and loss modulus values at the onset of melting, in particular when small amounts (1.25% by wt%) of CNTs are present. The characteristic bands were detected for the PBu/PEO and PBu/PEO/CNT samples by means of Raman and Fourier‐transform infrared spectroscopy. CNT addition increases the hydrophobicity via the increase in roughness as attained by atomic force microscopy. 相似文献
Electrospinning is a recently rediscovered method to produce non-woven nanowebs of which the individual polymer fibres have diameters of 50-500 nm. Applications require specific functionalities to be present at the surface. The use of additives in the electrospun solution provides an elegant alternative to functionalised polymers. This study has focused on the use of the static secondary ion mass spectrometry (S-SIMS) to characterise the surface composition of nanofibres electrospun from acetone solutions containing 15% (w/w) of poly(?-caprolactone) (PCL, molecular weight 40,000) and 0-15 mol% (relative to PCL) cetyltrimethylammonium bromide (CTAB). Specifically, the calibration of the relative signal intensities of structural ions from PCL and CTAB as a function of the local concentrations requires adequate reference samples to be prepared. In general, this step becomes a major bottleneck in nanoscale analysis. A relatively simple method using a combination of spincoating and hand barcoating of solutions has been developed. Its applicability and limitations for monitoring the surface enrichment of CTAB in PCL nanowebs are discussed. 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
Summary: Poly(N‐vinylpyrrolidone) (PVP) was used in two methods to prepare polymer nanofibers containing Ag nanoparticles. The first method involved electrospinning the PVP nanofibers containing Ag nanoparticles directly from the PVP solutions containing the Ag nanoparticles. N,N‐Dimethylformamide was used as a solvent for the PVP as well as a reducing agent for the Ag+ ions in the PVP solutions. In the second method, poly(vinyl alcohol) (PVA) aqueous solutions were electrospun with 5 wt.‐% of the PVP containing Ag nanoparticles. The Ag nanoparticles were evenly distributed in the PVA nanofibers. PVP containing Ag nanoparticles could be used to introduce Ag nanoparticles to other polymer nanofibers that are miscible with PVP.
TEM image of a PVA nanofiber electrospun with 5 wt.‐% of the PVP containing Ag nanoparticles. 相似文献
Resorbable polymer electrospun nanofiber-based materials/devices have high surface-to-volume ratio and often have a porous structure with excellent pore interconnectivity,which are suitable for growth and development of different types of cells.Due to the huge advantages of both resorbable polymers and electrospun nano fibers,re sorbable polymer electrospun nanofibers(RPENs)have been widely applied in the field of tissue engineering.In this paper,we will mainly introduce RPENs for tissue engineering.Firstly,the electrospinning technique and electrospun nanofiber architectures are briefly introduced.Secondly,the application of RPENs in the field of tissue engineering is mainly reviewed.Finally,the advantages and disadvantages of RPENs for tissue engineering are discussed.This review will provide a comprehensive guide to apply resorbable polymer electrospun nanofibers for tissue engineering. 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