PEO Nanofibers Research Articles

Toughened CFRPs via PEO Nanofibers: Effect of Water Ageing on Delamination

AbstractDelamination is a common failure mechanism affecting composite laminates. Thermoplastic poly(ethylene oxide) (PEO) nanofibers are recently proposed for toughening carbon fiber reinforced polymers (CFRPs), obtaining promising results. In the present work, PEO‐modified epoxy CFRPs underwent ageing in water for 1 month, and the interlaminar properties are assessed via double cantilever beam (DCB) and end‐notched flexure (ENF) tests. The Mode I delamination behavior of both PEO‐modified and unmodified commercial composite plates is compared. Water ageing slightly affects the mechanical properties of the nano‐modified laminates, though the interleaved nano‐reinforcement is water‐soluble. The achieved results are very encouraging and pave the way to the use of PEO nanofibrous mats for hindering delamination in composite laminates.

Biological activities of fig latex -loaded cellulose acetate/poly(ethylene oxide) nanofiber for potential therapeutics: Anticancer and antioxidant material

Cancer is a fatal disease, and unfortunately, the anticancer drugs harm normal cells. Plant's extracts are the golden key to solving this issue. In this research, fig latex - from Ficus carica- was encapsulated using cellulose acetate (CA) and poly (ethylene oxide) (PEO) polymers via electrospinning method (Fig@CA/PEO). Fig@CA/PEO nanofiber scaffold was characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The average fiber diameter was decreased with an increase in latex concentration from 715 nm to 583 nm. FT-IR spectroscopy indicated the presence of fig latex in Fig@CA/PEO nanofibers. Compared to 5-fluorouracil, Fig@CA/PEO nanofiber scaffold considered safe towards normal cells (WI-38). Moreover, the nanofiber scaffold was efficient against colon cancer cells (Caco) and liver cancer cells (HepG2) as it demonstrated IC50 values for cells by 23.97 μg/mL and 23.96 μg/mL, respectively. Besides, the nanofiber scaffold revealed mechanistic variations in apoptotic oncogenes; described by the upregulation of BCL2 and P21, combined by downregulation of p53 and TNF. Moreover, the nanofiber scaffold showed antioxidant activity counting 33.4, 36 and 41 % of DPPH scavenging as the fig latex concentration increased. The results demonstrate that the Fig@CA/PEO nanofiber scaffold is a promising substitute to traditional chemotherapy.

"Nano in Nano"-Incorporation of ZnO Nanoparticles into Cellulose Acetate-Poly(Ethylene Oxide) Composite Nanofibers Using Solution Blow Spinning.

In this work, the preparation and characterization of composites from cellulose acetate (CA)-poly(ethylene oxide) (PEO) nanofibers (NFs) with incorporated zinc oxide nanoparticles (ZnO-NPs) using solution blow spinning (SBS) is reported. CA-PEO nanofibers were produced by spinning solution that contained a higher CA-to-PEO ratio and lower (equal) CA-to-PEO ratio. Nanoparticles were added to comprise 2.5% and 5% of the solution, calculated on the weight of the polymers. To have better control of the SBS processing conditions, characterization of the spinning suspensions is carried out, which reveals a decrease in viscosity (two- to eightfold) upon the addition of NPs. It is observed that this variation of viscosity does not significantly affect the mean diameters of nanofibers, but does affect the mode of the nanofibers' size distribution, whereby lower viscosity provides thinner fibers. FESEM-EDS confirms ZnO NP encapsulation into nanofibers, specifically into the CA component based on UV-vis studies, since the release of ZnO is not detected for up to 5 days in deionized water, despite the significant swelling of the material and accompanied dissolution of water-soluble PEO. Upon the dissolution of CA nanofibers into acetone, immediate release of ZnO is detected, both visually and by spectrometer. ATR-FTIR studies reveal interaction of ZnO with the CA component of composite nanofibers. As ZnO nanoparticles are known for their bioactivity, it can be concluded that these CA-PEO-ZnO composites are good candidates to be used in filtration membranes, with no loss of incorporated ZnO NPs or their release into an environment.

Nanofibers with genotyped Bacillus strains exhibiting antibacterial and immunomodulatory activity.

Biofilm-associated diseases such as periodontitis are widespread and challenging to treat which calls for new strategies for their effective management. Probiotics represent a promising approach for targeted treatment of dysbiosis in biofilm and modulation of host immune response. In this interdisciplinary study, nanofibers with two autochthonous Bacillus strains 27.3.Z and 25.2.M were developed. The strains were isolated from the oral microbiota of healthy individuals, and their genomes were sequenced and screened for genes associated with antimicrobial and immunomodulatory activities, virulence factors, and transferability of resistance to antibiotics. Spores of two Bacillus strains were incorporated individually or in combination into hydrophilic poly(ethylene oxide) (PEO) and composite PEO/alginate nanofibers. The nanofiber mats were characterised by a high loading of viable spores (> 7 log CFU/mg) and they maintained viability during electrospinning and 6months of storage at room temperature. Spores were rapidly released from PEO nanofibers, while presence of alginate in the nanofibers prolonged their release. All formulations exhibited swelling, followed by transformation of the nanofiber mat into a hydrogel and polymer erosion mediating spore release kinetics. The investigated Bacillus strains released metabolites, which were not cytotoxic to peripheral blood mononuclear cells (PBMCs) in vitro. Moreover, their metabolites exhibited antibacterial activity against two periodontopathogens, an antiproliferative effect on PBMCs, and inhibition of PBMC expression of proinflammatory cytokines. In summary, the developed nanofiber-based delivery system represents a promising therapeutic approach to combat biofilm-associated disease on two fronts, namely via modulation of the local microbiota with probiotic bacteria and host immune response with their metabolites.

Protease Immobilization in Solution-Blown Poly(ethylene oxide) Nanofibrous Nonwoven Webs

Enzyme-functionalized solution-blown nonwoven (EFSBN) fibers were produced by a single-step solution blow spinning method that utilizes high-velocity gas to simultaneously extrude the codissolved polymer–solvent–enzyme spinning solution and evaporate solvent at mild conditions to form a nanofibrous web with preserved enzyme activity. A broad concentration range of 0.6–7.4 wt % protein of subtilisin A protease from Bacillus licheniformis was successfully entrapped by poly(ethylene oxide) (PEO) during solution blow spinning nonwoven web production. The presence of enzyme protein in the solid nanofibers was detected by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Time of flight-secondary ion mass spectroscopy and laser confocal microscopy revealed the immobilized enzymes were mainly positioned inside the fibers and homogeneously distributed throughout the webs. Scanning electron microscopy showed that the fiber shape and diameter of PEO nanofibers containing enzymes were irregular compared to PEO-only nanofibers. Residual enzyme activity in the webs was measured by redissolving fibers in buffer and comparing the released enzyme activity to nonimmobilized free enzyme using a casein substrate-based assay. Immobilized protease (1.3% (w/w) protein in solid dry nanofiber webs) retained more than 90% of the free enzyme activity. Protease immobilized in solid nanofiber webs exhibited long storage stability at ambient (∼22 °C) and 4 °C temperature storage conditions, with more than 60% remaining catalytic activity after 300 days compared to the initial activity. Immobilized protease had equally good thermal stability as a stabilized liquid commercial protease, both retaining above 95% of their initial activity after treatment for 12 h at 65 °C. In contrast, the same liquid protease diluted in buffer lost activity within 2 h at that temperature. The nondusting, readily aqueous-soluble EFSBN solid materials are easy to handle and have good storage stability compared to liquid products.

Fabrication of Water‐Soluble Polythiophene/Poly (sulfonic acid diphenyl aniline)/Polyethylene Oxide Electrospun Nanofibers and Their Antioxidant Activities

AbstractThe fabrication and antioxidant properties of polythiophene/poly(sulfonic acid diphenyl aniline)/polyethylene oxide electrospun nanofibers obtained in this study were brought to the literature for the first time. For this, polythiophene/poly(sulfonic acid diphenyl aniline)/polyethylene oxide (PTh/PSDA/PEO) nanofibers containing 5, 10, 20 and 40 % PTH/PSDA composite by weight were produced by electrospinning method. According to both CUPRAC and ABTS assays, these electrospun nanofibers were found to have antioxidant activity. According to both CUPRAC and ABTS assays, the highest antioxidant activity was obtained from PTh/PSDA/PEO4 electrospun nanofiber containing 40 % PTH/PSDA with values of 244 and 111 μg TE/mg, respectively. This nanofiber was found to be non‐toxic according to the MTT assay and its thermal stability was not much different from that of the PEO nanofiber. PTh/PSDA/PEO electrospun nanofibers were biocompatible, water‐soluble nanofibers that were candidates for use in many biological applications with further characterization. These electrospun nanofibers were characterized by FT‐IR, UV‐Vis.,1H NMR, XRD and TGA. Surface morphologies were investigated by SEM.

Impact of zinc salt counterion on poly(ethylene oxide) solution viscosity, conductivity, and ability to generate electrospun MOF/nanofiber composites

The effect of seeding poly(ethylene oxide), PEO, aqueous solutions with zinc acetate (ZA) and zinc chloride (ZC) on solution properties (e.g., viscosity and electrical conductivity) and the ability to electrospin nanofibers was investigated. The impacts of the type of Zn counterion and overall salt concentration on solution viscosity and electrical conductivity were correlated to the ability to electrospin nanofibers, as well as the resulting fiber morphology. In dilute PEO solutions, Zn salt addition reduced the PEO hydrodynamic radius ( R h ) and viscosity likely as a result of PEO chain envelopment of Zn cations, while in semi-dilute entangled regimes, Zn salt addition increased R h and viscosity likely due to interactions a single Zn cation with multiple polymer chains. The addition of Zn salts had limited effects on the overlap concentration ( c* ), but increased the entanglement concentration ( c e ), and the presence of either ZA or ZC enabled electrospinning of bead-free fibers at lower PEO concentrations (than without salt) because of the increased electrical conductivity of the solution. However, increasing the ZA concentration in solution had limited effect on fiber diameter and morphology, while raising the ZC concentration in solution resulted in the fusion of fibers into webs and films likely due to charge carryover. The resulting salt-doped PEO nanofibers were used as a template to synthesize a zeolitic imidazolate framework, ZIF-8, through a vapor-deposition approach exploiting the embedded Zn as nucleation sites for heterogeneous growth in a ‘Fiber-first’ strategy. • Aqueous poly(ethylene oxide) solutions were seeded with zinc salts. • Zinc salts, notably Zn acetate, reduced polymer concentration required to spin bead-free fibers. • Zinc chloride, especially at higher loadings, led to electrospun fused webs instead of fibers. • Zinc counterion type impacted solution conductivity and affected bead-free fiber development. • Zinc salt seeding enabled the vapor-phase growth of the zeolitic imidazolate framework ZIF-8.

Fast dissolving nanofibrous mats for diclofenac sodium delivery: Effects of electrospinning polymer and addition of super-disintegrant

Fast dissolving oral preparations have unique advantages such as rapid dissolution, fast onset of action, convenient administration, and enhanced bioavailability. Therefore, these formulations are proper choices for pain management. The aim of this study was to design and characterize nanofiber (NF) based fast dissolving oral preparations for diclofenac sodium (DS). Different NF-forming hydrophilic polymers were used for the preparation of fast dissolving oral mats and their disintegration time and dissolution rate were compared. DS was incorporated with high loading percentage (25%). The disintegration time showed the following order: PEO NFs > PVP NFs > PVA NFs. To further decrease disintegration time, a super-disintegrant was incorporated into the nanoformulations. The sodium starch glycolate (SSG) enriched NFs showed very rapid disintegration (0.4 s) and complete dissolution within 120 s. The XRD results confirmed the poorly crystalline nature of DS in NFs. FTIR indicated DS incorporation into NFs without any interaction with formulation components. The pH of NF solutions was around neutral and the system showed appropriate biocompatibility evaluated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Higher permeability of DS by incorporation into NFs was proved by permeation study through sheep buccal mucosa. The optimum formulation has great potential as a fast-dissolving mat for pain management.

Fabrication, characterization and in vitro evaluation of disulfiram-loaded cellulose acetate/poly(ethylene oxide) nanofiber scaffold for breast and colon cancer cell lines treatment

Cancer and microbial infections threaten human health. Currently, chemotherapeutic drugs for cancer lack selectivity between normal and cancer cells, exacerbating this problem. Effective anticancer drug encapsulation is the golden key to solving this issue. Disulfiram (DS), an anticancer drug, has low solubility and selectivity and to tackle this concern, cellulose acetate (CA) and poly (ethylene oxide) (PEO) was selected as a matrix to prepare nanofiber containing DS (DS@CA/PEO) via electrospinning technique. DS@CA/PEO nanofiber was characterized by SEM, FTIR, TGA, and X-rd patterns and the results confirmed DS incorporation in CA/PEO nanofiber. DS@CA/PEO nanofiber scaffold showed higher safety than DS-free on human normal cells (Wi-38) with revealing similar anticancer activity of DS-free against colon cancer line (Caco-2) and breast cancer line (MDA-MB 231). This higher selectivity of DS@CA/PEO towards cancer cells than normal cells was associated with maintaining apoptotic activity and aldehyde dehydrogenase-inhibitory potency of DS. The latter efficacy led to eradicating colon and breast cancer stem cells, as evidenced by flow cytometry. Moreover, DS@CA/PEO nanofiber scaffold showed potent antibacterial activity (in vitro) against both Gram-negative and Gram-positive bacteria. These results investigated that DS@CA/PEO nanofiber scaffold could be a potential dual candidate as a selective anticancer and antimicrobial agent.

On the thermogravimetric analysis of polymers: Polyethylene oxide powder and nanofibers

AbstractThermogravimetric analysis of polyethylene oxide (powder and nanofibers obtained by force spinning water or chloroform solutions of polyethylene oxide) was studied using different theoretical models such as Friedman and Flynn‐Wall‐Ozawa. A semiempirical approach for estimating the “sigmoid activation energy” from the thermal degradation was suggested and confirmed by the experimental data on PEO powder and nanofibers' mats. The equation allowed for calculating a “sigmoid activation energy” from a single thermogram using a single heating rate without requiring any model for the actual complex set of chemical reactions involved in the thermal degradation process. For PEO (powder and nanofibers obtained from water solutions), the “sigmoid activation energy” increased as the heating rate was increased. The sigmoid activation energy for PEO mats obtained from chloroform solutions exhibited a small decrease as the heating rate was increased. Thermograms' derivatives were fitted to determine the coordinates of the inflection points. The “sigmoid activation energy” was compared to the activation energy determined from the Flynn‐Wall‐Ozawa model. Similarities between the thermal degradation of polyethylene oxide powder and of the nanofibers obtained from water solutions were discussed. Significant differences between the sigmoid activation energies of the mats obtained from water and chloroform solutions were reported.

Confined crystallization and chain conformational change in electrospun poly(ethylene oxide) nanofibers

This study focused on understanding the confined crystallization of poly(ethylene oxide) (PEO) in electrospun nanofibers. The effect of thermal treatment on PEO crystallization was also studied. An electrospinning process with a rotating drum collector enabled stretching and aligning of polymer chains, which resulted in the formation of a planar zigzag conformation. The confined environment in nanofibers facilitated an ordered crystal arrangement, resulting in an increase in the degree of crystallinity with a decrease in the fiber diameter. By contrast, large fibers extended solvent evaporation, which resulted in large crystallite sizes. The confined geometry and mechanical force provided by a rotating collector induced the preferred crystal orientation parallel to the fiber axis. Upon thermal annealing, the stretched PEO chains relaxed, resulting in a change from the metastable zigzag conformation to a stable helical conformation. Thermal treatment monotonically increased the melting temperature, degree of crystallinity, and crystallite size of PEO nanofibers regardless of the fiber diameter but did not influence the orientation of the organized crystals. The confinement effect on the chain conformation and crystallization behavior of poly(ethylene oxide) (PEO) in electrospun nanofibers was investigated. The PEO chains in electrospun nanofibers were tightly packed and exhibited a zigzag conformation. Increasing the fiber diameter reduced the packing of polymer chains, resulting in increases in the melting temperature and crystallite size. Thermal treatment relaxed the stretched chains, which induced a change from the metastable zigzag conformation to a stable helical conformation. Additionally, the melting temperature, degree of crystallinity, and crystallite size increased with increasing annealing temperature.

The Fabrication of Poly(Σ-caprolactone)-Poly(ethylene oxide) Sandwich Type Nanofibers Containing Sericin-Capped Silver Nanoparticles as an Antibacterial Wound Dressing.

In this study, antibacterial, synthetic poly(Σ-caprolactone)-poly(ethylene oxide) (PCL-PEO) multilayer nanofibers were produced by an electrospinning method. The material was synthesized in 3 layers. The upper-lower protective layers were produced by PCL nanofibers and the intermediate layer was produced from PEO nanofiber containing sericin-capped silver nanoparticles (S-AgNPs). The electrospinning conditions in which nano-sized, smooth, bead-free fibers were obtained was determined to be an applied voltage of 20 kV, a flow rate of 8 μL/min and a distance between the collector and the needle tip of 22 cm for the PCL layer (dissolved at a 12% g/mL concentration in a chloroform:methanol (3:2) solvent mixture) layer. For the S-AgNPs doped PEO layer (dissolved at a 3.5% g/mL concentration in water), the corresponding conditions were determined to be 20 kV, 15 μL/min and 20 cm. To characterize the three-layer material that consisted of PCL and S-AgNPs doped PEO layers, FTIR and SEM analyses were performed, and the water retention capacity, in situ degradability and antibacterial activity of the material was investigated. According to SEM analysis, the fibers obtained were found to be nano-sized, smooth and bead-free and the average size of the nanofibers forming the PCL layer was 687 nm while the average size of the fibers forming the PEO layer was 98 nm. Antibacterial activity tests were performed using gram-positive (Staphylococcus aureus ATCC 6538) and gram-negative (Escherichia coli ATCC 25922) bacteria and the resulting biomaterial was found to have antimicrobial effect on both gram-negative and gram-positive bacteria. It was determined that the 3-layer material obtained in this study can be used as a wound dressing.

Surface Functionalization of PEO Nanofibers Using a TiO2 Suspension as Sheath Fluid in a Modified Coaxial Electrospinning Process

Surface Functionalization of PEO Nanofibers Using a TiO2 Suspension as Sheath Fluid in a Modified Coaxial Electrospinning Process

Cellulose reinforced electrospun chitosan nanofibers bio-based composite sorbent for water treatment applications

Electrospun chitosan–polyethylene oxide/TEMPO-oxidized cellulose (CS–PEO/TOC) bio-based composite was fabricated for the first time for water treatment applications. This new concept allows cellulose and chitosan to be combined in a simpler and efficient way, avoiding the use of harmful solvents, compared to previously published related work. The “Sandwich-like” material is composed of a porous oxidized cellulosic fibers central core (TOC handsheet) and a thin layer of electrospun CS–PEO nanofibers on both sides of the core. Average diameters for CS–PEO and TOC were 159.3 ± 33.7 nm and 21.7 ± 5.1 µm, respectively. Fourier Transform Infrared Spectroscopy (FTIR) was carried out on the bio-based composite. Results suggest that no covalent bonds are involved but rather electrostatic interactions occur which allows bonding of the electrospun nanofiber layers on TOC core and no delamination. CS–PEO electrospinning time was varied to study the effect of nanofiber’s coating weight on strength, permeability and adsorption capacity of the bio-based material. Mechanical properties of the composite were improved over the electrospun nanofiber mat. The CS–PEO provides greater elasticity (strain%) and the TOC provides a higher tensile strength to the material. However, tensile index was reduced by 48% with electrospinning time, while burst index was almost constant. The best conditions were achieved for 2 h electrospinning time. Under these conditions, a high permeable material (290.13 L/m2 hbar) was developed. The adsorption capacity for Cu (II) ions reached up to 27% with only 12 mg of chitosan onto the CS–PEO/TOC (12.42 mg/g). The data fit better to the pseudo-second order model, suggesting chemisorption as the main mechanism involved for copper adsorption. This study opens-up potential opportunities for the development of a robust material for wastewater applications at an industrial scale.

A colorimetric and fluorometric polydiacetylene biothiol sensor based on decomposition of a pyridine-mercury complex

Biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) participate in numerous cellular functions and physiological processes. Because changes in the levels of these biological important substances are associated with various clinical disorders and diseases, methods for their selective sensitive and quantitative detection are in high demand. In the current study, we developed a new, selective and sensitive colorimetric and fluorometric biothiol chemosensor that is comprised of a mercury-complexed, pyridine-containing polydiacetylene (PDA). Owing to its high affinity toward sulfur, biothiols promote decomposition of the pyridine-mercury complex in the PDA in conjunction with colorimetric and fluorescence changes. Specifically, upon addition of biothiols the new chemosensor undergoes a blue-to-red color transition and generates red fluorescence. Moreover, incorporation of the chemosensor in electrospun PEO nanofibers leads to an enhanced sensitivity for biothiol detection. The strategy developed in this study should be applicable to the design of other thiol-specific sensors that utilize pyridine-containing conjugated molecules.

Anticellular PEO coatings on titanium surfaces by sequential electrospinning and crosslinking processes

Titanium implants having some superior properties for tissue replacements have been widely used in biomedical fields. However, the implants are vulnerable to bacterial attacks and therefore they must be modified. In this study, two kinds of titanium surfaces, bare (Ti-b) and sandpapered (Ti-p) titanium, were used and electrospinning method was utilized for coating them with poly(ethylene oxide) (PEO) nanofibers with average diameter of 180 nm. In order to obtain insoluble coating, the PEO nanofibers were crosslinked by UV-initiating and crosslinking agent, pentaerythritol triacrylate (PETA), in the presence of UV irradiation at 366-nm wavelength. Fibroblastic MC3T3-E1 preosteoblasts and S. epidermidis bacteria were cultured on these surfaces to investigate their attachment and proliferation behavior. The preosteoblasts cultured on Ti-p exhibited better initial adhesion than that of Ti-b at the end of the 4 h of incubation period, which reveals the importance of surface roughness. The bacteria adhered and colonized on Ti-b surfaces at the end of the 24 h of incubation. In contrast, Ti surfaces modified by the PEO nanofibers inhibited cellular and bacterial attachment significantly. This study discloses that electrospinning and subsequent crosslinking of PEO can be evaluated as an effective approach for creating anticellular coatings for Ti implants.

Monte Carlo simulation of molecular and structural properties of mono- and bi-dispersed poly(ethylene oxide) nanofibers

Molecular and structural properties of poly(ethylene oxide), PEO, nanofibers with different diameters and molecular weights were investigated using Monte Carlo simulation of coarse-grained models on high coordination lattice. PEO nanofibers made up of mono- and bi-dispersed chains of CH3-(OCH2CH2)x-OCH3 where x = 13 to 53, with diameter ranged from 7.4 to 16.4 times the radius of gyration of PEO chains, were analyzed. For mono-disperse chains, as a result of increasing molecular weight, the bulk density increases and the molecular size at the surface is decreased more than the nanofibers composed of shorter chain length. There is higher degree of parallel orientation of the chains and bonds at the surface and a broader region over which this bond orientation pertains. For nanofibers with mixed molecular weight, shorter chains tend to segregate at the surface and the density of short chain component is higher in this region. Compared to mono-disperse nanofibers, the properties of longer chains do not significantly change, whereas the orientation of chains and bonds for low molecular weight polymers become more anisotropic orientation in the presence of longer chains.

Nanofibres made from biocompatible and biodegradable polymers, with potential application as medical textiles

An important and growing part of the textile industry is the medical and related healthcare and hygiene sector. Recently, ultrafine fiber webs made from biocompatible and biodegradable polymers have been obtained by the electrospinning process. Their unique properties such as high surface area-to-volume ratio, small pore sizes, high porosity, and the possibility of incorporation therapeutic compounds into the electrospun nanofibers has attracted the researcher’s attention lately. This paper presents the obtaining of PEO and PVA nanofibers.

Plasma-treated poly(ethylene oxide) nanofibers containing tea tree oil/beta-cyclodextrin inclusion complex for antibacterial packaging

This work describes the effect of cold nitrogen plasma to enhance the antibacterial activity of poly(ethylene oxide) (PEO) nanofibers containing antibacterial agent. Beta-cyclodextrin (β-CD) and tea tree oil (TTO) were used as a host-guest to form water-soluble inclusion complex. The encapsulation efficiency of TTO in inclusion complex could reach 73.23% at 60°C. As antibacterial agent, the inclusion complex was encapsulated into PEO matrix by electrospun. After plasma treatment, the release efficiency of antibacterial agent from PEO nanofibers was improved. As a result, the antibacterial activity of PEO nanofibers was enhanced accordingly. The plasma-treated nanofiber membranes achieved the highest antibacterial activity against Escherichia coli O157:H7, which was tested on the beef for 7d, with inhibition efficiently of 99.99% whether at 4°C or 12°C. The plasma-treated PEO nanofiber membranes containing TTO/β-CD inclusion complex (TTO/β-CD-IC) can prolong the shelf-life of beef, suggesting it has potential application in active food packaging.

Effects of solvent on structures and properties of electrospun poly(ethylene oxide) nanofibers

ABSTRACTPoly(ethylene oxide) (PEO) nanofibers were prepared by electrospinning PEO solution with a mixed solvent of ethanol and deionized water. The results show that the mixed solvent system has noteworthy influences on structures and properties of electrospun PEO nanofibers, including molecular chain orientation, crystallinity degree, surface morphology, fiber diameter, diameter distribution, spinnability, and productivity. With increasing ethanol content in the mixed solvent, wrinkly morphologies appear on the surface of PEO nanofibers due to a high evaporation rate of ethanol during electrospinning process. The dielectric constant, dipole moment, conductivity, density, boiling point, and solubility parameter of the mixed solvent become lower with the ethanol content increasing. Besides, the hydrogen‐bonding interactions between PEO and solvents become weaker. As a result, PEO nanofibers with larger diameters, lower molecular chain orientation, and crystallinity degree are obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45787.