Diameter Distribution Of Nanofibers Research Articles

Preparation and properties of bio-based PA56/SiO2–NH2 composite nanofiber membranes for high efficiency oil-water separation

With the continuous development of environmental protection and resource recycling demands, the development of bio-based separation membrane materials has increasingly attracted attention. Bio-based polyamide 56 (PA56), exhibiting excellent hydrophilicity, spinnability, and mechanical properties, is expected to complement and replace traditional separation membrane materials. In this study, the electrospinning preparation and structural control of PA56 nanofiber membranes were achieved through the optimization of PA56 content and mixed solvent ratios. The study found that when the PA56 content was 16 wt% and the formic acid to acetone ratio in the mixed solvent was 8:2, the nanofiber diameter distribution was the most uniform. Building on this, amino-functionalized modified silica (SiO2–NH2) nanoparticles were introduced to prepare PA56/SiO2–NH2 composite nanofiber membranes featuring a cobweb-like nanofiber network and micro-nodule structure. The effects of the addition of SiO2–NH2 nanoparticles on the morphology, structure, and properties of the fiber membranes were studied. The results indicate that the control of the mixed solvent ratio and the addition of SiO2–NH2 nanoparticles led to the formation of a cobweb-like nanofiber network and micro-nano nodular structure on the nanofiber surface, enhancing the hydrophilicity of PA56 nanofiber membranes. The M − 3 membrane with a nanoparticle addition amount of 0.8 wt% exhibited high hydrophilicity and underwater superoleophobic properties, achieving efficient separation of stable oil-in-water emulsions with a separation efficiency of 99.8 %. This work provides a new bio-based membrane material and its preparation method for treating oily wastewater using the membrane separation method.

Self-assembled electrospun PVA/CMC/PEO composite fiber film material with enhanced dye adsorption performance for wastewater treatment

As society rapidly progresses, environmental issues, including water pollution and ecosystem degradation are steadily worsening. In this work, a novel functional nanofiber composite film based on polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and polyethylene oxide (PEO) were prepared by using electrospinning technique. The incorporation of PEO facilitated a more concentrated nanofiber diameter distribution. The prepared composite films were further modified with glutaraldehyde vapor to enhance their hydrophobicity and improve pore-making capabilities on the fiber surface. The nanocomposite fiber film, with its simple preparation process, cost-effectiveness, and environmental friendliness, exhibits a promising prospect in addressing environmental challenges. Notably, the designed nanofiber films demonstrated remarkable efficiency in dye adsorption, owing to the high specific surface area of the fibers and the selective binding of active groups on the fiber surface to the dyes. Moreover, they showed good reusability, which is of great significance for adsorbents. Therefore, the obtained composite films from environmentally friendly preparation process has great application potential in wastewater treatment and dye removal.

Natural Biopolymer–Hydrogel Nanofibers for Antibacterial Applications

Abstract This study used a suitable solvent such as deionized water and aqueous acetic acid to dissolve completely polymer blends such as gelatin: chitosan: pullulan (G: CS: PUL) with mixing ratios of 80:10:10, 60:20:20, 40:30:30, and 20:40:40, respectively. The properties of natural polymer mixtures, viscosity, surface tension, and electrical conductivity were examined, and the fiber diameter and nanofiber diameter distribution were measured. Increasing the gelatin content from 20% to 80% in the G: CS: PUL increases the properties of biopolymer solutions, such as viscosity, surface tension, and electrical conductivity of 157%, 14%, and 37%, respectively. In addition, increasing the gelatin content reduces the contact angle by 55%. In other words, the average diameter of the nanofibers increased from 91.177 ± 27.162 to 212.46 ± 67.91 nm with the increase of the gelatin content by 40–100% in the blends and obtaining uniform fibers without beads, which enhanced the ability of nanofibers for releasing into the aqueous media and enhancing their use in packaging food such as (80:10:10 and 60:20:20). Moreover, the blend ratio 60:30:30 (G:CS: PUL) had better resistance to bacterial growth; the inhibition zone diameters were 26 and 23 mm for E. coli and S. aureus and had better average crystalline size and crystallinity.

High-efficiency retention of ultrafine aerosols by electrospun nanofibers

The versatility of nanofibrous polymeric materials makes them attractive for developing respiratory protective equipment. Ultrafine nanofibers effectively trap the most penetrating aerosols and exhibit consistent performance compared to conventional electret filters. Advanced nanofiber manufacturing technologies such as electrospinning can functionalize filter materials, enhancing them with unique antibacterial, catalytic, sensory, and other properties. Much of the current research in nanofibrous air filtration focuses on using nanofibers for lightweight personal protective equipment such as N95 respirators, but their use for higher levels of respiratory protection required for chemical, biological, radiological, and nuclear (CBRN) protection has not yet been comprehensively explored. In this study, we tested the hypothesis that electrospun filters could provide the particle filtration efficiency and breathing resistance required by the National Institute for Occupational Safety and Health Standard for CBRN air-purifying respirators. Our manufactured nanofibrous filters demonstrated submicron aerosol retention efficiency of > 99.999999%, which is four orders of magnitude better than the requirements of the CBRN standard. They also had a breathing resistance of ~ 26 mmH2O, which is more than twofold lower than the maximum allowable limit. Although the filter material from the gas mask cartridge currently in service with the U.S. military demonstrated a higher quality factor than electrospun filters, the comparative analysis of filter morphology suggested ways of improving nanofibrous filter performance by tuning nanofiber diameter distribution.

PVA/PEO/PVA-g-APEG nanofiber membranes with cytocompatibility and anti-cell adhesion for biomedical applications

To prepare novel medical dressings with excellent comprehensive properties, this work uses the polyvinyl alcohol-allyl polyethylene glycol graft copolymer (PVA-g-APEG) synthesized in our previous work as a modifier. The polyvinyl alcohol (PVA)/polyethylene oxide (PEO)/PVA-g-APEG nanofiber membranes with different PVA-g-APEG contents are successfully prepared by electrospinning technology. The biomimetic natural extracellular matrix structure of nanofiber membranes is achieved by regulating the PVA-g-APEG contents. As the content of PVA-g-APEG is 4 wt%, the diameter distribution of nanofibers is the narrowest. The average diameter of nanofibers reaches the minimum value of 267.18 nm, and the porosity of nanofiber membranes reaches the maximum value of 77.90%. Meanwhile, nanofiber membranes possess excellent biocompatibility. The absorption capacity of the nanofiber membranes for different liquids is improved with higher PVA-g-APEG content. The nanofiber membranes become soft and slippery after contact with liquid, effectively avoiding adhesion with cells. The cell proliferation rate is higher than 100%, and the cytotoxicity grade is 0. Additionally, the mechanisms of intermolecular interactions, crystallization and mechanical properties change of nanofiber membranes are discussed systematically. It provides a method and idea for preparing high-strength PVA/PEO nanofiber membranes and realizing the practical application of PVA/PEO composite systems in medical dressings.

Orthogonal Optimization Research on Various Nozzles of High-Speed Centrifugal Spinning.

High-speed centrifugal spinning is a burgeoning method of fabricating nanofibers by use of the centrifugal force field. This article studied four different spinning nozzles, which were called stepped nozzle, conical-straight nozzle, conical nozzle, and curved-tube nozzle, to explore the optimal nozzle structures for fabricating nanofibers. According to the principle of centrifugal spinning, the spinning solution flow states within the four nozzles were analyzed, and the solution outlet velocity model was established. Then, the structural parameters of the four kinds of nozzles were optimized with the spinning solution outlet velocity as the test index by combining the orthogonal test and numerical simulation. Based on the orthogonal test results, the influence of nozzle structure parameters on the solution outlet velocity was analyzed, and the best combination of parameters of the centrifugal spinning nozzle structure was obtained. Subsequently, the four kinds of nozzles were used to fabricate nanofibers in the laboratory, under different solution concentration, motor rotation speed, and outlet diameters. Finally, the scanning electron microscope (SEM) was applied to observe the morphology and surface quality of nanofibers. It was found that the surface of nanofibers manufactured by the conical-straight nozzle and curved-tube nozzle was smoother than that by stepped and conical nozzles, and the fiber diameter by the conical-straight nozzle was minimal, followed by curved-tube nozzles, stepped nozzles, and conical nozzles in the diameter distribution of nanofibers.

Novel free surface electrospinning for preparing nanofibers and its mechanism study

In order to meet the increasing demand for nanofibers and overcome the disadvantages of traditional electrospinning technology, it is necessary to research an electrospinning device that can produce nanofibers efficiently. In this paper, a free surface electrospinning device was improved, and a spherical section free surface electrospinning device was developed to prepare high-quality polyacrylo-nitrile nanofibers in batches. Meanwhile, MAXWELL 3-D software was used to simulate the electric field distribution of the spherical section free surface electro-spinning with solution reservoirs of different spherical radii. The influence of the spherical radius on the spinning effect was analyzed to study the spinning mechanism. The results showed that when the applied voltage was 40 kV, the electric field distribution of the spherical section free surface electrospinning with a larger spherical radius was more uniform, the nanofiber diameter was larger, the nanofiber diameter distribution was more uniform, and the yield of nanofibers was higher. When the spherical radius was 75 mm, the quality of nanofibers was better, and the yield could reach the maximum value of 14.35 g per hour, due to its higher average electric field intensity and uniform electric field distribution.

Valorization of Waste Chicken Feathers: Fabrication and Characterization of Novel Keratin Nanofiber Conduits for Potential Application in Peripheral Nerve Regeneration

Flexible, porous, biocompatible, and biodegradable tubular keratin nanofibers were fabricated as nerve regeneration conduits. Keratin was extracted from waste chicken feathers and then blended with polyvinyl alcohol and transformed into nanofiber conduits by electrospinning. The nanofiber conduits had average diameters that ranged from 170 to 234 nm. The nanofibers’ average diameter decreased when the keratin content was increased. In contrast, the range of nanofiber diameter distribution narrowed, suggesting that as nanofibers became thin, their numbers increased, thus reducing the interfacial spaces between them. The analysis confirmed the presence of keratin protein in nanofibers, guaranteeing biocompatibility and biodegradation. TGA showed that keratin improved the thermal stability and hydrophilicity of the nanofibers.

Efficient dye removal from wastewater by functionalized macromolecule chitosan-SBA-15 nanofibers for biological approaches

Today, one of the major concerns of environmental health is the purification of colored wastewater due to its high contamination. The present study focused on the synthesis and comprehensive characterization of environmentally friendly electrospinning membranes based on Chitosan cross linked with SBA-15 as a novel adsorbent for dye removal. Unlike most micro structured adsorbents, CTS-SBA-15 nanofibers with their special properties such as density, porosity, high surface-to-volume ratio, small and layered structures, etc. have a very high adsorption capacity to remove macromolecular pollution and microorganisms. Adsorbents were synthesized and functionalized, then produced by electrospinning instrument in the form of nanofibers sheets. In this study, FT-IR, XRD, FE-SEM, TEM, and tensile tests were employed to characterize the functional groups, surface morphology and pore diameter distribution of nanofibers. The influence of different analytical parameters was investigated to obtain the optimum conditions for the adsorption process. The optimum conditions for adsorption process obtained as following: type of adsorbent: CTS-SBA-15-NH2, pH: 2, adsorbent dosage: 0.05 g, initial concentration: 60 and 40 mg/l and contact time: 40 min, which followed from the Langmuir and Freundlich isotherms. So, it was found that CTS-SBA-15 can act as inexpensive and efficient adsorbent for the dye removal from the contaminated water.

Spinning solution flow model in the nozzle and experimental study of nanofibers fabrication via high speed centrifugal spinning

Comparing with traditional methods, high speed centrifugal spinning has the advantages of simple fabrication principle and high preparation efficiency. In this study, the flow law of spinning solution in the nozzle and the effect of spinning parameters on the morphology of nanofibers were explored. A motion model of spinning solution in the nozzle was established to study the velocity distribution of spinning solution in the nozzle, moreover, the relationship between the critical rotational speed required to form the jet and the spinning parameters was studied. It was found that the current velocity of spinning solution was mainly concentrated at the axis of the nozzle and shifted in the direction of Coriolis acceleration. The relationship between spinning parameters and the critical rotational speed was verified. The critical rotational speed for forming the spinning jet was directly proportional to the spinning solution concentration and inversely proportional to the nozzle diameter. Polyoxyethylene (PEO) nanofibers were fabricated by selectively adjusting spinning parameters and characterized by using scanning electron microscopy (SEM). The results showed that the diameter distribution of nanofibers could be adjusted by changing the spinning parameters, such as spinning solution concentration, rotational speed, nozzle length, nozzle diameter and collection distance. The high speed centrifugal spinning has the potential to produce single continuous nanofibers efficiently.

Effect of Dynamic Viscosity on Nanofiber Diameters and Electrical Conductivity of Polyacrylonitrile Nanofibers Doped Nano-Cu Particles

In this study, pure polyacrylonitrile nanofibers in the diameter range of 200-500 nm and PAN / Cu composite nanofibers in 200-600 nm diameter range were produced at applied voltage of 15 kV. The distribution of fiber diameters, the dynamic viscosities of the solutions and the electrical conductivity (EC) of the produced fibers have been examined as a function of copper nanoparticles content (1%, 3% and 5% by weight). Results showed that the dynamic viscosity of the electrospinning solution is an important parameter on the nanofiber morphology as well as on the nanofiber diameter distribution. Taken together, the data analysis showed that the highest EC value was 38x10-2 S/cm, which was obtained from nanofibers produced by electrospinning solution containing %1 Cu nanoparticle having a dynamic viscosity value of 577.7 mPa.s. The addition of Cu nanoparticles increased the EC of pure PAN nanofibers by a factor of 2.37. In addition, further analysis of pure PAN nanofibers and %1 Cu/PAN nanofibers have been performed by XRD, contact angle and TGA devices. Results showed that the TGA degradation curves of both pure PAN and Cu-based PAN nanofibers presented the same behavior. In DSC analysis, the glass transition temperature of pure PAN nanofibers was observed at 112 °C, while no glass transition temperature was observed for PAN nanofibers containing 1% Cu.

Shear‐aided high‐throughput electrospinning: A needleless method with enhanced jet formation

AbstractIn this article, we introduce a novel high productivity electrospinning setup for scaling up the classical method. We propose a new spinneret concept, which allows the shearing of the polymer solution prior to electrospinning. Most of the solutions used in electrospinning are shear‐thinning, that is, as they are sheared, they show smaller resistance against the deformations caused by the electrostatic field. Therefore, enhanced Taylor‐cone formation can be achieved, and it also gives a hand in controlling the nanofiber morphology easily, even during operation. In this study, we investigated the influence of shearing on the electrospinning process and the fiber morphology. When shearing was applied by rotation, the operation became more stable and the fiber morphology improved. Multiple jets were observed along the circular edges of the spinneret, also became thinner as an effect of the shearing rotation. The average diameter of the electrospun nanofibers was decreased by 18% with rotation speed applied, compared to those of the nonrotating condition (0 rpm). Besides that, we found that the electrospun nanofiber diameter distribution was significantly different for the various rotation speeds for which we found an applicable explanation with the aid of high‐speed camera recordings.

Physico-mechanical and in vitro characterization of electrically conductive electrospun nanofibers of poly urethane/single walled carbon nano tube by great endothelial cells adhesion for vascular tissue engineering

Cardiovascular diseases (CVD) because of blood vessel disease are considered as one of the most frequent causes for mortality in all over the world. Recently, blood vessel tissue engineering is identified as one the promising strategies in order to overcome CVD. Accordingly, using Nano technology provides many benefits in blood vessel tissue engineering. In Present research Unique electrical, mechanical and biochemical properties of SWNT combined with electrospun polyurethane nanofiber was investigated as a functional composite scaffold for vascular tissue engineering. SWNT and polyurethane nanofibers incorporation indicated a biomechanical behavior similar to native artery. The scaffold morphological properties have been investigated by the use of scanning electron microscopy. With respect to the results, nanofiber diameter distribution was narrowed down by increasing SWNT content, while mean nanofiber diameter increased from 40 nm up to 140 nm. Physico-chemical characterization using FTIR, DSC, XRD and Raman test, demonstrated the nanoparticle appropriate dispersion and interaction to the polyurethane macromolecule. Along with increasing SWNT content up to the 2% (W/W) ultimate stress and young modulus increased 3 and 11 time, compared to pure PU, respectively. Structures electrical conductivity was increased from 0.0013 s/cm to 0.36 s/cm along with the increasing of SWNT content up to 2%. SWNT unique properties modulated samples hydrophilicity, and also contact angle of nanofiber scaffolds decreased from 1000 to 770. By passing 7 days, in vitro cell culture demonstrated dense layer of endothelial cells, which is crucial for blood vessel tissue engineering. Obtained results confirmed that electrospun poly urethane-SWNT scaffold could be considered as an appropriate candidate for blood vessel tissue engineering.

Electrospun Mats: From White to Transparent with a Drop

AbstractIn this article, the transparency of hydrophilic electrospun mats is studied. Results showing how transmittance varies under the action of water are presented. It is observed that swelling plays a crucial role in the transmittance of the material, changing it from opaque to transparent when it is wet. Atomic force microscope measurements show that the diameter distribution of nanofibers is modified during both the wetting and the drying of the mats. Using these distributions and modeling the change in the relative refractive index as a composite material, a qualitative explanation of the mat scattering behavior by using the Mie scattering theory for cylinders has been done. The obtained results indicate that changes on the optical response produced by water contact are different according to the mat thickness: samples with smaller thicknesses can act as a water sensor with a persistent response over time, while samples with thicknesses greater than 7 µm can act as sensors for drying time.

Fabricated narrow diameter distribution nanofiber for an air filtration membrane using a double rings slit spinneret

A needleless electrospinning setup called “Needleless Double Rings Slit Electrospinning” was proposed for the first time. The control pump transports solution to the double rings slits through an insulated infusion tube. High voltage is applied to the metal ring and electric force exceeds the surface tension and viscosity, and multiple jets are spontaneously formed on the top of solution surface. Different spinning process parameters, including solution concentration, applied voltage, collection distance and spinning time, have an influence on nanofiber diameter distribution. The morphology of nanofibers has been observed using scanning electron microscopy. It is worth noting that narrow diameter distribution nanofibers have been fabricated using a novel double rings slit spinneret. Nanofiber diameter distribution has determined the mean pore diameter, pore diameter distribution, filtration efficiency and filtration resistance. The final results show that the pore size and filtration property for nanofiber membranes are significantly related with nanofiber diameter distribution. Narrow diameter nanofibers have contributed to the improvement of filtration properties for nanofiber membranes.

Multifunctional e-spun colloidal nanofiber structures from various dispersed blends of PVA/ODA-MMT with PVP/ODA-MMT, poly(VP-alt-MA) and AgNPs incorporated polymer complexes as electro-active platforms

This work presented a new approach to fabricate polymer nanocomposites films with nanofiber structures from solution blends of poly(vinyl alcohol) + octadecyl amine-montmorillonite (ODA-MMT) (matrix) with poly(N-vinylpyrroli- done) + ODA-MMT (partner-1), poly(N-vinylpyrrolidone-alt-maleic anhydride) ((poly(VP-alt-MA)) + (ODA-MMT) (partner-2) and their silver (Ag)-carrying polymer complexes by electrospinning. Chemical and physical structures, surface morphologies, thermal behaviors, electrical conductivity and thermal resistance parameters of nanofiber structures were in- vestigated. Poly(VP-alt-MA) was used both as a crosslinker and a donor of the hydrophilic groups such as -COOH and -NH-C=O amide from pyrrolidone ring. Reactive poly(VP-alt-MA), in situ generated Ag nanoparticles (AgNPs) and orig- inal partner polymer had an significant effect on the morphology and diameter distribution of nanofibers. High and excel- lent conductive behaviors were observed for the homopolymer and copolymer of VP based fiber structures, respectively. Upon successive chemical cross-linking of the nanofiber structures by reactive partner copolymer, the conductivity of nanofiber films as electro-active platforms dramatically increased to 3.90·10 -2 S·cm -1 at room temperature. Comparative analysis results also indicated that electrical properties strongly depended on the loaded reactive organoclay and in situ gen- erated AgNPs.

Thermodynamic Studies on Polyvinylpyrrolidone Solution Systems Used for Fabrication of Electrospun Nanostructures: Effects of the Solvent

ABSTRACTIn this research, we investigate the influence of polyvinylpyrrolidone (PVP) solution systems on the morphology of the PVP nanofibers fabricated by electrospinning of PVP solutions prepared in different organic solvents, including ethanol (EtOH), propanol (PrOH), chloroform, N‐methyl‐2‐pyrrolidone (NMP), and N,N‐dimethylformamide (DMF) and then compared with the experimental results. First, by considering the electrospun solutions behavior, the thermodynamic studies were evaluated then Hansen solubility theory was applied to select the desirable solvent systems. The dissolving power of the solvents for PVP was obtained in the following order: DMF > NMP >> chloroform > PrOH > EtOH. It seems that every solvent, which is able to dissolve PVP polymer, shows different spinning characteristics under identical conditions of processing parameters. By using PrOH, chloroform, and NMP solvents, electrospun nanofibers’ average diameter was decreased intensively but at the same time beads formation was observed. We investigated that EtOH was a desirable solvent for PVP to fabricate fibers with z micrometer diameter distribution, but because of its low dissolving power it is suitable for microfiber synthesis with the electrospinning process. Based on the Hansen theory and experimental results, the PVP/DMF solutions showed desirable characteristics for the electrospinning system. Furthermore, the PVP nanofiber's uniformity of the PVP/DMF solution was higher than other solvent systems, which mean that fiber diameter distribution is scanty than others. Finally, it has been demonstrated that with an appropriate solvent the nanofiber diameter distribution and formation of beads can be controlled by Hansen theory.

Synthesis of polyacrylonitrile/polyamidoamine composite nanofibers using electrospinning technique and their dye removal capacity

In this paper, polyacrylonitrile (PAN)–polyamidoamine (PAMAM) composite nanofibers were synthesized using electrospinning technique and their dye removal ability was investigated. The functional groups, morphology, total surface area and pore diameter distribution of nanofibers were studied by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), the Brunauer–Emmett–Teller (BET) and the Barret–Joyner–Halend (BJH) methods, respectively. Direct red 80 (DR80) and Direct red 23 (DR23) were used as the model compounds. The effects of adsorbent dosage, initial dye concentration, and solution pH on dye removal were evaluated. Kinetics and isotherm of dye adsorption were found to conform to pseudo-second order kinetics and Langmuir model, respectively. The maximum dye adsorption capacity (Q0) of PAN/PAMAM composite nanofiber was 1666.66 and 2000 mg/g for DR80 and DR23, respectively.

PVDF hollow fiber and nanofiber membranes for fresh water reclamation using membrane distillation

Polyvinylidene fluoride hollow fiber and nanofibrous membranes are engineered and successfully fabricated using dry-jet wet spinning and electrospinning techniques, respectively. Fabricated membranes are characterized for their morphology, average pore size, pore size distribution, nanofiber diameter distribution, thickness, and water contact angle. Direct contact membrane distillation (DCMD) performances of the fabricated membranes have been investigated using a locally designed and fabricated, fully automated MD bench scale unit and DCMD module. Electrospun nanofibrous membranes showed a water flux as high as 36 L m−2 h−1 whereas hollow fiber membranes showed a water flux of 31.6 L m−2 h−1, at a feed inlet temperature of 80 °C and at a permeate inlet temperature of 20 °C.

Characterization and structure analysis of PLGA/collagen nanofibrous membranes by electrospinning

AbstractPoly(DL‐lactide‐co‐glycolide) (PLGA)/marine collagen nanofibrous membranes (PCNMs) with different weight ratio of PLGA to collagen were fabricated by an electrospinning method. The morphology and diameter distribution of electrospun nanofibers were investigated by scanning electron microscopy (SEM). SEM images showed that the morphology and diameter distribution of the nanofibers were mainly affected by the concentration of the solution, weight ratio of the PLGA/collagen, and applied electric voltage, respectively. To investigate the cell responses, MG‐63 cells isolated from a human mandible were cultured onto various substrates and their adhesion, spreading, and proliferation were examined. Immunofluorescent staining of MG‐63 cultured on the PCNMs demonstrated homogeneous localization of F‐Actin and vinculin in their cytoplasms. However, no mature adhesive structures were observed in the cell cultured on other substrates. Also, the cells seeded on the materials proliferated. These results suggest that PCNMs strongly support the attachment and growth of osteosarcoma cells. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012