Average Fiber Size Research Articles

Fabric pre-treated with Vitex negundo L essential oil as a preventive tool against mosquito bite

Despite its beneficial properties and the efficiency of essential oil in controlling mosquitoes and other hematopoietic insects, this biocontrol agent has several significant limitations, ranging from its chemical instability to its short protection time and sensitivity to oxidation. This research aimed to address these limitations by altering the surface functionality using encapsulated Vitex negundo essential oil (VnEO). The VnEO was extracted by hydrodistilation and analysed by GC–MS. The oil was β-cyclodextrin (β-CD) encapsulated and monochlorotriazine (MCT) modified to improve its fabric interaction and stability, while histological and immunohistochemical examinations were conducted to determine its safety. The fabrics were subjected to FT-IR, SEM, XRD, TGA, fiberometric, and Zeta potential analysis, while the repellency study was conducted in an olfactometer. Insecticidal monoterpenes and sesquiterpenes were confirmed by GC–MS, and an entrapment efficiency of 94.3% was achieved. The repellent interaction with the fabric was confirmed by the formation of two intense bands at 3277 (O–H) and 1710 cm−1 (C=O), broad diffraction peaks at 17.30° and 38.30–57.10° about a 4.70% increase in average fibre size and a 18.8% decrease in pore size, and lower fibre thermal stability. The surface of the fabric is negatively charged, causing an enhancement in the adsorption and affinity of VnEO by grafting of β-CD/MCT. The dermatological investigation suggests that the oil has no significant toxic effects. In conclusion, the encapsulation and fabric grafting employed are effective and safe for the preparation of a long-lasting repellent fabric.

Electrospun Smart Oxygen Indicating Tag for Modified Atmosphere Packaging Applications: Fabrication, Characterization and Storage Stability.

Pack integrity is essential for the success of modified atmosphere packaging of food products. Colorimetric oxygen leak indicators or tags are simple and smart tools that can depict the presence or absence of oxygen within a package. However, not many bio-based electrospun materials were explored for this purpose. Ultraviolet light-activated kappa-carrageenan-based smart oxygen indicating tag was developed using the electrospinning technique in this study and its stability during storage was determined. Kappa-carrageenan was used with redox dye, sacrificial electron donor, photocatalyst, and solvent for preparing oxygen indicating electrospun tag. Parameters of electrospinning namely flow rate of the polymer solution, the distance between spinneret and collector, and voltage applied were optimized using Taguchi L9 orthogonal design. Rheological and microstructural studies revealed that the electrospinning solution was pseudoplastic and the mat fibers were compact and non-woven with an average fiber size of 1–2 microns. Oxygen sensitivity at different oxygen concentrations revealed that the tag was sensitive enough to detect as low as 0.4% oxygen. The developed tag was stable for at least 60 days when stored in dark at 25 °C and 65% RH. The developed mat could be highly useful in modified atmosphere packaging applications to check seal integrity in oxygen devoid packages.

Preparation and Characterization of Cellulose Nanofibers from Banana Pseudostem by Acid Hydrolysis: Physico-Chemical and Thermal Properties

Cellulose is a biopolymer that may be derived from a variety of agricultural wastes such as rice husks, wheat straw, banana, and so on. Cellulose fibril that is reduced in size, often known as nanocellulose (NC), is a bio-based polymer with nanometer-scale widths with a variety of unique properties. The use of NC as a reinforcing material for nanocomposites has become a popular research issue. This research paper focuses on the production of banana pseudostem cellulose nanofiber. Nano-sized fiber was obtained from banana pseudostem through several processes, namely, grinding, sieving, pre-treatment, bleaching, and acid hydrolysis. The product yield was found to be 40.5% and 21.8% for Musa acuminata and Musa balbisiana, respectively, by the weight of the raw fiber. The reduction in weight was due to the removal of hemicellulose and lignin during processing. Transmission electron microscopy (TEM) analysis showed that the average fiber size decreased from 180 µm to 80.3 ± 21.3 nm. Finally, FTIR analysis showed that the fibers experienced chemical changes after the treatment processes.

The effect of different sizes of cross‐linked fibers of biodegradable electrospun poly(ε‐caprolactone) scaffolds on osteogenic behavior in a rat model in vivo

AbstractA variety of biodegradable polymer scaffolds serving the purpose of mimicking the extracellular matrix have been studied; however, no effective recipe has yet been developed for scaffold pore size and overall percent porosity, which are optimal for cell penetration in vitro and tissue growth in vivo. Thus, this study reports the effect of poly(ε‐caprolactone) (PCL) fiber size and scaffold porosity on the osteogenic behavior of scaffolds in a rat model in vivo. It was revealed that scaffolds with an average fiber size of 9.2 μm, and 4.05 μm, and combination of 0.6 μm submicrofibres (upper layer) with 9.2 μm microfibres (bottom layer) in hybrid two‐layer scaffolds behave significantly differently with respect to macrophage reactions and tissue regeneration in a rat model in vivo. Poor macrophage response at implantation tests into the bone tissue in vivo reveals the advantages of microfibrous PCL scaffolds with a fiber size of 4.05 μm and hybrid scaffolds with submicro‐ and microfibres for stimulation of reparative osteogenesis over microfibrous scaffolds with a fiber size of 9.2 μm. The combination of submicro‐ and microfibrous layers in hybrid scaffolds provides an opportunity to control the shape and density of bone trabeculae during regeneration processes in vivo.

Design of Asymmetric Nanofibers-Membranes Based on Polyvinyl Alcohol and Wool-Keratin for Wound Healing Applications.

The development of asymmetric membranes—i.e., matching two fibrous layers with selected composition and morphological properties to mimic both the epidermis and dermis—currently represents one of the most promising strategies to support skin regeneration during the wound healing process. Herein, a new asymmetric platform fabricated by a sequential electrospinning process was investigated. The top layer comprises cross-linked polyvinylalcohol (PVA) nanofibers (NFs)—from water solution—to replicate the epidermis’s chemical stability and wettability features. Otherwise, the bottom layer is fabricated by integrating PVA with wool-keratin extracted via sulfitolysis. This protein is a biocompatibility polymer with excellent properties for dermis-like structures. Morphological characterization via SEM supported by image analysis showed that the asymmetric membrane exhibited average fiber size—max frequency diameter 450 nm, range 1.40 μm—and porosity suitable for the healing process. FTIR-spectrums confirmed the presence of keratin in the bottom layer and variations of keratin-secondary structures. Compared with pure PVA-NFs, keratin/PVA-NFs showed a significant improvement in cell adhesion in in vitro tests. In perspective, these asymmetric membranes could be promisingly used to confine active species (i.e., antioxidants, antimicrobials) to the bottom layer to support specific cell activities (i.e., proliferation, differentiation) in wound healing applications.

Flow-induced bending deformation of electrospun polymeric filtration membranes using the “leaky” bulge test

In service, hydraulic flow is usually perpendicular to the plane of electrospun fiber mats for water filtration, inducing an out-of-plane deformation. In this paper, we have investigated the out-of-plane deformation response of wet electrospun polyacrylonitrile fiber mats with distinct average constituent fiber diameters of 232 ± 36 nm, 727 ± 148 nm and 1017 ± 80 nm, but with nominally similar thicknesses and areal densities using the classical bulge testing technique. The resultant pressure-deflection relationships are incompatible with constitutive models for out-of-plane deformation of continuum materials. Rather, the fiber mats exhibited a one-half dependence (p∼h12) governed by fiber deflection, and pressure asymptote indicative of steady-state fluid percolation, but influenced by the mats areal densities. In addition, the apparent bending rigidity increased with increasing fiber diameter. In the range tested for fiber mats with average fiber size of 232 nm, increase in mat thickness did not noticeably alter measured rigidities, although evidence of slight increase in pressure asymptote is observed. Cyclic flow rate tests provided evidence of good recoverability as well as minimal topological modifications.

Gallic acid encapsulated pea flour‐based nanofibers produced by electrospinning as a potential active food packaging material

AbstractThe main aim of the article was to produce gallic acid‐loaded pea flour/polyethylene oxide (PEO)‐based nanofibers through the electrospinning method as an alternative active packaging material. Incorporation of gallic acid caused significant changes in both solution properties and fiber morphology. Increasing gallic acid concentration resulted in increasing conductivity and decreasing consistency index, by the way decreasing average fiber size diameter. In thermogravimetric analysis (TGA), gallic acid addition resulted in a decrease in thermal degradation value of nanofibers. In addition to these changes, new chemical bands formed were an indicator of the successful encapsulation of gallic acid in Fourier‐transform infrared (FTIR) spectra. Nanofibers also showed promising results in terms of encapsulation of bioactive compounds. Therefore, gallic acid‐loaded pea flour/PEO‐based nanofibers might be considered as a promising active packaging material.

Incorporation of astrocaryum vulgare (tucuma) oil into PCL electrospun fibers

The aim of this study was to incorporate tucuma oil (Astrocaryum vulgare) into PolyCaprolactone (PCL) electrospun fibers and evaluate its physicochemical properties and cell viability. FTIR and DRX confirmed that tucuma oil (TO) does not affect the chemical properties of PCL and that the oil was loaded into the PCL microstructure, while TGA analysis showed that the oil increased the thermal stability of the polymeric fibers. SEM showed that the addition of the oil modified fibers structure by reducing the average fiber size from 5.5 μm to 1.7 μm for TO loaded samples. Cell viability assay demonstrated an increment on cell proliferation from 80% of pure PCL to 100% for samples containing TO. Therefore, it can be concluded that tucuma oil can be incorporated into PCL to form fibers by electrospinning, without meaningful changes in its physicochemical properties and increasing its biocompatibility.

Synthesis of PVDF/SiO2 nanofiber membrane using electrospinning method as a Li-ion battery separator

Abstract This work reported synthesis of PVDF/SiO2 (Polyvinilidene fluoride/Silica) nanofiber membrane by electrospinning method that was used as a separator in li-ion battery. The effect of the SiO2 nanoparticle addition to the PVDF nanofiber membrane to improve membrane characteristics which include porosity, temperature stability, mechanical strength and the stability of battery capacity were systematically investigated. The electrospinning parameter was adjusted at a voltage of 15 kV, the flow rate of 1,5 ml/hour, the distance between needle to collector 17 cm and spinning time for 1 h. The immersion of PVDF membrane in colloid SiO2 nanoparticles was carried out for 1 h. Nanofiber membrane was characterized by SEM (Scanning Electron Microscope), n-butanol intrusion, the dimensional changes before and after heat treatment, stress–strain mechanical measurements with autograph and battery analyzer. The PVDF nanofiber membrane has a beaded fiber with an average fiber size was ∼656 nm. The nanoparticle SiO2 formed double layer on the PVDF membrane. The porosity of PVDF without SiO2 and PVDF/SiO2 3000 ppm is 57% and 70%, respectively. The effect of addition SiO2 to mechanical strength were increased until 2.7 MPa and the membrane were stable at 150 °C for 30 min. The electrochemical performance test by using the produced PVDF membrane has a higher specific capacity than using PP membrane that is 104.6 mAh/g. The addition of SiO2 nanoparticles increased the PVDF membrane capacity stability for 6 cycles by the decline of specific capacity of 42.7 mAh/g for PVDF membrane to 18.7 mAh/g with the addition of 3000 ppm SiO2 nanoparticles.

Porcine Lung-Derived Extracellular Matrix Hydrogel Properties Are Dependent on Pepsin Digestion Time.

Hydrogels derived from decellularized lungs are promising materials for tissue engineering in the development of clinical therapies and for modeling the lung extracellular matrix (ECM) in vitro. Characterizing and controlling the resulting physical, biochemical, mechanical, and biologic properties of decellularized ECM (dECM) after enzymatic solubilization and gelation are thus of key interest. As the role of enzymatic pepsin digestion in effecting these properties has been understudied, we investigated the digestion time-dependency on key parameters of the resulting ECM hydrogel. Using resolubilized, homogenized decellularized pig lung dECM as a model system, significant time-dependent changes in protein concentration, turbidity, and gelation potential were found to occur between the 4 and 24 h digestion time points, and plateauing with longer digestion times. These results correlated with qualitative scanning electron microscopy images and quantitative analysis of hydrogel interconnectivity and average fiber diameter. Interestingly, the time-dependent changes in the storage modulus tracked with the hydrogel interconnectivity results, while the Young's modulus values were more closely related to average fiber size at each time point. The structural and biochemical alterations correlated with significant changes in metabolic activity of several representative lung cells seeded onto the hydrogels with progressive decreases in cell viability and alterations in morphology observed in cells cultured on hydrogels produced with dECM digested for >12 and up to 72 h of digestion. These studies demonstrate that 12 h pepsin digest of pig lung dECM provides an optimal balance between desirable physical ECM hydrogel properties and effects on lung cell behaviors.

Physical, Mechanical, and Bioactive Properties of Pig Lung-Derived ECM Hydrogels are Dependent on the Duration of Pepsin Digestion

Extracellular matrix (ECM) hydrogels derived from decellularized lungs are promising materials for tissue engineering, in the development of clinical therapies, and for modeling the lung ECM in vitro. Characterizing and controlling the resulting physical, biochemical, mechanical, and biologic properties of decellularized ECM after enzymatic solubilization and gelation is thus of key interest. As the role of enzymatic pepsin digestion in effecting these properties has been understudied, we investigated the digestion time-dependency on key parameters of the resulting ECM hydrogel. Using resolubilized homogenized decellularized pig lung ECM (dECM) as a model system, significant time-dependent alterations in the protein concentration, turbidity, and gelation potential occurred between 4 and 24 hours of digestion, plateauing at longer digestion times. These results correlated with qualitative SEM images and quantitative analysis of hydrogel interconnectivity and average fiber diameter. Interestingly, the time-dependent changes in the storage modulus tracked with the hydrogel interconnectivity results, while the Young's modulus values were more closely related to average fiber size at each time point. The structural and biochemical alterations translated to significant changes in metabolic activity of several representative lung cells seeded onto the hydrogels with progressive decreases in cell viability and alterations in morphology observed in cells cultured on hydrogels produced with dECM digested for greater than 12 and up to 72 hours of digestion. These studies demonstrate that 12hr structured pepsin digest of pig lung dECM provides an optimal balance between desirable physical dECM hydrogel properties and effects on lung cell behaviors.

Aligned biomimetic scaffolds based on carbon nanotubes-reinforced polymeric nanofibers for knee meniscus tissue engineering

Many strategies in tissue engineering have been developed in order to provide potential treatments for Knee meniscal injuries since it is a high incidence lesion and without effective treatment available in clinical practice. The success of this approach is directly related to the creation of a scaffold able to reproduce the complex extracellular matrix of the native meniscus with adequate mechanical properties. Here we fabricated an aligned biomimetic scaffold, based on carbon nanotube (CNT)-reinforced polymeric nanofibers. For that, scaffolds with both circumferentially and radially aligned polycaprolactone fibers were developed from a specific electrospinning setup and incorporated with two different concentrations of CNT: 0.05% and 0.10%. Characterization by scanning electron microscopy confirmed the spatial distribution and the alignment of the electrospun nanofibers as well as a decrease in average fiber size with the addition of CNT (the presence of CNT was confirmed by transmission electron microscopy). Dynamic mechanical analysis and biological assays showed an improvement in the mechanical properties related to increased CNT content without influence in mesenchymal stem cells survival. These findings suggest a potential applicability of this nanocomposite for knee meniscus tissue engineering.

Angiotensin receptor blockade mimics the effect of exercise on recovery after orthopaedic trauma by decreasing pain and improving muscle regeneration.

Our tibial fracture orthopaedic injury model in mice recapitulates the major manifestations of complex trauma, including nociceptive sensitization, bone fracture, muscle fibrosis and muscle fibre loss. Delayed exercise after complex orthopaedic trauma results in decreased muscle fibrosis and improved pain Losartan, an angiotensin-receptor blocker with anti-fibrotic abilities, recapitulates the effect of exercise on post-injury recovery and may provide an enhanced recovery option for those who are unable to exercise after injury ABSTRACT: Chronic pain and disability after limb injury are major public health problems. Early mobilization after injury improves functional outcomes for patients, although when and how to implement rehabilitation strategies remains a clinical challenge. Additionally, whether the beneficial effects of exercise can be reproduced using pharmacological tools remains unknown and may benefit patients who are unable to exercise as a result of immobilization. We developed a murine model of orthopaedic trauma combining tibia fracture and pin fixation with muscle damage. Behavioural measures included mechanical nociceptive thresholds and distances run on exercise wheels. Bone healing was quantified using microcomputed tomagraphic scanning, and muscle fibre size distribution and fibrosis were followed using immunohistochemistry. We found that the model provided robust mechanical allodynia, fibrosis and a shift to smaller average muscle fibre size lasting up to 5weeks from injury. We also observed that allowing 'late' (weeks 1-2) rather than 'early' (weeks 0-1) exercise after injury resulted in greater overall running activity and greater reversal of allodynia. In parallel, the late running paradigm was associated with reduced muscle fibrosis, earlier increase in muscle fibre diameter and a short-term benefit in reducing callus volume. Providing the anti-fibrotic angiotensin receptor blocker losartan to mice in drinking water reduced both allodynia and muscle fibrosis. Combining losartan and late exercise provided no additional benefit. We conclude that early healing after orthopaedic trauma must be allowed prior to the initiation of exercise to achieve optimal pain, functional and physiological outcomes and that losartan is a viable candidate for translational studies.

Electrohydrodynamic printing of sub-microscale fibrous architectures with improved cell adhesion capacity

ABSTRACT A solution-based electrohydrodynamic (EHD) printing strategy was developed to fabricate sub-microscale biopolymeric fibres to mimic the tiny architectures of native extracellular matrix (ECM) for enhanced cellular performance. It was found that when the working voltage was significantly reduced to 500 V, sub-microscale fibres as well as user-specific patterns with an average fibre size of 193 ± 51 nm can be stably EHD printed. The presented process is applicable to biocompatible polycaprolactone (PCL) for the fabrication of water-stable sub-microscale fibrous architectures. The resultant sub-microscale fibres exhibited unique capability to enhance cellular adhesion, spreading and orientation in comparison with conventional microscale fibres fabricated by conventional melt-based EHD printing. The EHD-printed fibres can be precisely stacked to form multilayer sub-microscale structures. The proposed solution-based EHD printing process provides a promising strategy to fabricate sub-microscale biopolymeric architectures that could be further functionalised by the incorporation of bioactive components for enhanced tissue regeneration.

Characterization of the Properties of Electrospun Blended Hybrid Poly(Vinyl Alcohol)_Aloe Vera/Chitosan Nano-Emulsion Nanofibrous Membranes

The spinning solution of blended hybrid poly (vinyl alcohol) (PVA)_Aloe Vera (AV) with various concentrations (0%, 3%, 10% and 15%) of chitosan nanoemulsion (CSNe) were electrospun under optimized conditions of high DC voltage 15 kV, distance of spinneret tip to collector plate 16.5 mm and spinneret diameter 0.8 mm. This work aims to manufacture the blended hybrid PVA_AV/CSNe nanofibrous membranes and characterize the solution and fiber properties, and tensile properties of the nanofibrous membranes by varying CSNe concentrations. Scanning electron microscopy (SEM) results revealed that beads-free fiber structure featured in all electrospun membranes with relatively homogeneous fiber size distribution. An increase of CSNe concentration from 0% to 15% reduces the average fiber size from 366 nm to 180 nm and increase tensile strength from 2,52  0.54 MPa to 6.18  0.15 MPa and tensile modulus from 7.5  1.06 MPa to 21.9  9.88 MPa of the membranes, respectively. The tensile strength of the present blended hybrid PVA_AV/CSNE nanofibrous membranes with 15% CSNe concentration and tensile modulus of that with all CSNe concentrations are included in the range of the natural skin properties: i.e. (5.00 – 30.00 MPa) and (4.6 – 20.0 MPa) for tensile strength and modulus, respectively. Such data suggest the potential use of the membranes as wound dressing material in the near future.

Design and characterization of dexamethasone-loaded poly (glycerol sebacate)-poly caprolactone/gelatin scaffold by coaxial electro spinning for soft tissue engineering

The aim of this research was to fabricate dexamethasone (Dex)-loaded poly (glycerol sebacate) (PGS)-poly (caprolactone) (PCL)/gelatin (Gt) (PGS-PCL/Gt-Dex) fibrous scaffolds in the form of core/shell structure which have potential application in soft tissues. In this regard, after synthesize and characterizations of PGS, PGS-PCL and gelatin fibrous scaffolds were separately developed in order to optimize the electrospinning parameters. In the next step, coaxial electrospun fibrous scaffold of PGS-PCL/Gt fibrous scaffold with PGS-PCL as core and Gt as shell was developed and its mechanical, physical and chemical properties were characterized. Moreover, degradability, hydrophilicity and biocompatibility of PGS-PCL/Gt fibrous scaffold were evaluated. In addition, Dex was encapsulated in PGS-PCL/Gt fibrous scaffold and drug release was assessed for tissue engineering application. Results demonstrated the formation of coaxial fibrous scaffold with average porosity of 79% and average fiber size of 294nm. Moreover, PGS-PCL/Gt fibrous scaffold revealed lower elastic modulus, ultimate tensile and ultimate elongation than those of PGS-PCL scaffold and more close to mechanical properties of natural tissue. Furthermore, lower contact angle of PGS-PCL/Gt than that of PGS-PCL demonstrated improved surface hydrophilicity of scaffold. DEX release was sustained over a period time of 30days from the scaffolds via three steps consisting of an initial burst release, secondary linear phase release pattern with slower rate over 20days followed by an apparent zero-order release phase. MTT observations demonstrated that there was no evidence of toxicity in the samples with and without Dex. Our findings indicated that core/shell PGS-PCL/Gt-Dex fibrous could be used as a carrier for the sustained release of drugs relevant for tissue engineering which makes it appropriate for soft tissue engineering.

Evaluation of PVA biodegradable electric conductive membranes for nerve regeneration in axonotmesis injuries: the rat sciatic nerve animal model.

The therapeutic effect of three polyvinyl alcohol (PVA) membranes loaded with electrically conductive materials - carbon nanotubes (PVA-CNTs) and polypyrrole (PVA-PPy) - were tested in vivo for neuro-muscular regeneration after an axonotmesis injury in the rat sciatic nerve. The membranes electrical conductivity measured was 1.5 ± 0.5 × 10-6 S/m, 579 ± 0.6 × 10-6 S/m, and 1837.5 ± 0.7 × 10-6 S/m, respectively. At week-12, a residual motor and nociceptive deficit were present in all treated groups, but at week-12, a better recovery to normal gait pattern of the PVA-CNTs and PVA-PPy treated groups was observed. Morphometrical analysis demonstrated that PVA-CNTs group presented higher myelin thickness and lower g-ratio. The tibialis anterior muscle, in the PVA-PPy and PVA-CNTs groups showed a 9% and 19% increase of average fiber size area and a 5% and 10% increase of the "minimal Feret's diameter," respectively. No inflammation, degeneration, fibrosis or necrosis were detected in lung, liver, kidneys, spleen, and regional lymph nodes and absence of carbon deposits was confirmed with Von Kossa and Masson-Fontana stains. In conclusion, the membranes of PVA-CNTs and PVA-PPy are biocompatible and have electrical conductivity. The higher electrical conductivity measured in PVA-CNTs membrane might be responsible for the positive results on maturation of myelinated fibers. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1267-1280, 2017.

Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions

Washing clothes made from synthetic materials has been identified as a potentially important source of microscopic fibres to the environment. This study examined the release of fibres from polyester, polyester-cotton blend and acrylic fabrics. These fabrics were laundered under various conditions of temperature, detergent and conditioner. Fibres from waste effluent were examined and the mass, abundance and fibre size compared between treatments. Average fibre size ranged between 11.9 and 17.7μm in diameter, and 5.0 and 7.8mm in length. Polyester-cotton fabric consistently shed significantly fewer fibres than either polyester or acrylic. However, fibre release varied according to wash treatment with various complex interactions. We estimate over 700,000 fibres could be released from an average 6kg wash load of acrylic fabric. As fibres have been reported in effluent from sewage treatment plants, our data indicates fibres released by washing of clothing could be an important source of microplastics to aquatic habitats.

Electrospinning of nanofibers: Characterization of jet dynamics and humidity effects

ABSTRACTElectrospinning is a method to produce submicron polymer fibers for a wide range of applications. In many applications, the average electrospun fiber size and uniformity are important for the product's performance and process economics. Thus, it is desirable for electrospinning to achieve consistent and controllable fiber diameters. However, the current state-of-the-art electrospinning process can result in variable fiber diameters, both run-to-run and during a run. This paper investigates how the operating regime as well as several important process factors affect fiber diameter using a vision-based system. For aqueous polyethylene oxide (PEO) solutions, it is found that the relative humidity has a strong effect on fiber diameter. Correlations between measurable parameters and fiber diameter are also developed to provide the ability to achieve the desired fiber diameters. The jet dynamics are experimentally identified through step response for development of appropriate control strategies.

Effect of filler content on morphology and physical–chemical characteristics of poly(vinylidene fluoride)/NaY zeolite-filled membranes

Poly(vinylidene fluoride) electrospun membranes have been prepared with different NaY zeolite contents up to 32 wt%. Inclusion of zeolites induces an increase of average fiber size from ~200 nm in the pure polymer up to ~500 nm in the composite with 16 wt% zeolite content. For higher filler contents, a wider distribution of fibers occurs leading to a broader size distribution between the previous fiber size values. Hydrophobicity of the membranes increases from ~115o water contact angle to ~128o with the addition of the filler and is independent on filler content, indicating a wrapping of the zeolite by the polymer. The water contact angle further increases with fiber alignment up to ~137°. Electrospun membranes are formed with ~80 % of the polymer crystalline phase in the electroactive β phase, independently on the electrospinning processing conditions or filler content. Viability of MC3T3-E1 cells on the composite membranes after 72 h of cell culture indicates the suitability of the membranes for tissue engineering applications.