Solution Blow Spinning Technique Research Articles

Solution blow spun piezoelectric nanofibers membrane for energy harvesting applications

Energy harvesting systems have benefited from the use of one-dimensional nanostructures such as nanofibers. For example, the conversion of mechanical energy to electrical energy has paved the way for nanofibers to be used in a wide range of applications. PVDF (polyvinylidene fluoride) has long been regarded as a promising material for piezoelectric applications. Furthermore, the solution blow spinning (SBS) technique, with its simple setup, can mass-produce nanofibers with the required properties for applications needing great flexibility while also attaining high piezoelectricity. The aim of this research is to investigate how electric voltage can be generated from flexible piezoelectric materials such as SBS PVDF nanofibers. Meanwhile, the nanofibers mats have been integrated into a basic setup that stimulates the generation of DC voltage under mechanical pressure produced by footsteps. The work followed a morphological characterization using SEM and studying the β-phase of the fabricated fibers using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), and it was found that β phase content for solution blow spun nanofibers reached 80% and the β-crystalline phase was enhanced due to the transformation from α to β phases. Our manufactured SBS nanofibers can create electric voltage under the influence of mechanical stresses, to simulate the foot step pressure, with varying amplitude and vibrational frequency, according to piezoelectric analysis.

Chitosan/PCL nanofibrous films developed by SBS to encapsulate thymol/HPβCD inclusion complexes for fruit packaging

In this work, the solution blow spinning (SBS) technique was used to rapidly fabricate the thymol (THY)/2-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complexes loaded chitosan (CS)/polycaprolactone (PCL) nanofibrous films for fruit preservation and packaging. XRD results indicated that the THY/HPβCD inclusion complexes were successfully incorporated into the CS/PCL nanofibers. The nanofibrous films had an increase of average diameters of nanofibers from 243.84 nm to 560.55 nm, an enhancement of water vapor permeability, a decrease of the crystallinity, and a hydrophilic surface after the incorporation. FTIR and thermal analysis showed that the thermal stability was also improved due to the formation of hydrogen bonds between THY/HPβCD inclusion complexes and CS/PCL nanofibers. The developed films obtained a long-term continuous release of THY during 240 h, and had a good antifungal activity in vitro and in vivo. The above results indicated the promising prospects of SBS in developing antifungal nanofibrous films for postharvest fruit.

Production of nanofibers from solution blow spinning (SBS)

The solution blow spinning technique was used, for the first time, to produce nanofiber of ultra-high molecular weight polyethylene (UHMWPE). The diameter of the nanofiber was smaller than that produced by the electrospinning process. This technique produces nanofibers on a rotating target by dragging a polymeric gel solution through a needle with heated concentric nozzles. The external nozzle, high-pressure air, pulls the polymeric solution through the internal nozzle. The gel polymeric solution is kept stirred, until used on a heated reservoir. The effect of working distance, injection pressure, and solution concentration was investigated. SEM images show that the diameters of the fibers produced ranged from 150 nm to 230 nm for ultra-high molecular weight polyethylene. The results indicate that the average fiber diameter was influenced by the solution concentration, while the morphology of nanofibers was controlled by the injection pressure and the working distance. Additionally, the thermal behavior and hydrophobicity were evaluated.

Formation of copper oxide II in polymer solution-blow-spun fibers and the successful non-woven ceramic production

Copper oxide II is a p-type semiconductor that can be used in several applications. Focusing on producing such material using an easy and low-cost technique, we followed an acetate one-pot-like route for producing a polymer precursor solution with different acetates:PVP (polyvinylpyrrolidone) weight ratios. Then, composite nanofibers were produced using the solution blow spinning (SBS) technique. The ceramic CuO samples were obtained after a calcination process at 600 °C for 2 h, applying a heating rate of 0.5 °C/min. Non-woven fabric-like ceramic samples with average diameters lower than 300 nm were successfully obtained. SEM images show relatively smooth fibers with a granular morphology. XRD shows the formation of randomly oriented grains of CuO. In addition, FTIR and XRD analyses show the CuO formation before the heat treatment. Thus, a chemical reaction sequence was proposed to explain the results.

The effect of surface morphology on endothelial and smooth muscle cells growth on blow-spun fibrous scaffolds

This study aimed to analyze the growth of two types of blood vessel building cells: endothelial cells (ECs) and smooth muscle cells (SMCs) on surfaces with different morphology. Two types of materials, differing in morphology, were produced by the solution blow spinning technique. One-layer materials consisted of one fibrous layer with two fibrous surfaces. Bi-layer materials consisted of one fibrous-solid layer and one fibrous layer, resulting in two different surfaces. Additionally, materials with different average fiber diameters (about 200, 500, and 900 nm) were produced for each group. It has been shown that it is possible to obtain structures with a given morphology by changing the selected process parameters (working distance and polymer solution concentration). Both morphology (solid versus fibrous) and average fiber diameter (submicron fibers versus microfibers) of scaffolds influenced the growth of ECs. However, this effect was only visible after an extended period of culture (6 days). In the case of SMCs, it was proved that the best growth of SMCs is obtained for micron fibers (with an average diameter close to 900 nm) compared to the submicron fibers (with an average diameter below 900 nm).

Effect of two-step calcination on the formation of nickel oxide hollow nanofibers

1D (one-dimensional) hollow nanofibers are of great technological interest. Their formation can be controlled by tuning the calcination process. However, the formation mechanism through the control of the burning stage is still debated in the literature. Herein, the influence of calcination in two steps on the morphology of hollow nanofibers of nickel oxide (NiO), prepared by solution blow spinning (SBS) technique, was investigated. A systematic study using a variety of characterization techniques suggests that a prolonged residence time in the initial step of calcination produces nanofibers with a better definition of the hollow region with better control of tubular wall thickness. Statistically, the calcination methodology studied here does not affect the outer diameter of nanofibers, as shown by Analysis of Variance (ANOVA) and Tukey’s method. According to our findings, the formation mechanism is influenced by gas diffusion and phase separation during fiber spinning and heat treatment, which suggests that neither the Kirkendall effect nor the Ostwald ripening process can be solely responsible for the formation hollow fibers. These findings contribute to a better understanding of the formation of metal-oxide hollow nanofibers induced by heat treatment.

Paramagnetic Meissner Effect and Current Flow in YBCO Nanofiber Mats

Microstructural and magnetic characterizations of YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-δ</sub> nanowire fabric-like samples were performed. Fabric-like ceramic superconductors are nanoporous materials and can be applied, e.g., in magnetic shielding, since the porous morphology makes them extremely light-weight and effectively to be cooled. The samples were produced by the solution blow spinning (SBS) technique, starting from a sol-gel solution of the precursor materials in polyvinyl-alcohol. The morphology of the samples was characterized by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction with the aim to analyze the possible current paths. The magnetic hysteresis loops revealed typical polycrystalline behavior, and field-cooling in various small applied fields shows the presence of the paramagnetic Meissner effect (PME), but in a distinctly different way as compared to melt-texured Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> CaCu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8+δ</sub> or Nb.

Optimum heat treatment to enhance the weak-link response of Y123 nanowires prepared by Solution Blow Spinning

Although the production of YBa2Cu3O7-δ (Y123) has been extensively reported, there is still a lack of information on the ideal heat treatment to produce this material in the form of one dimension nanostructures. Thus, by means of the Solution Blow Spinning technique, metals embedded in polymer fibers were prepared. These polymer composite fibers were fired and then investigated by thermogravimetric analysis. The maximum sintering temperatures of heat treatment were chosen in the interval 850 °C–925 °C for 1 h under oxygen flux. SEM images allowed us to determine the wire diameter as approximately 350 nm for all samples, as well as to map the evolution of the entangled wire morphology with the sintering temperature. XRD analysis indicated the presence of Y123 and secondary phases in all samples. Ac magnetic susceptibility and dc magnetization measurements demonstrated that the sample sintered at 925 °C/1 h is the one with the highest weak-link critical temperature and the largest diamagnetic response.

Metallophthalocyanine/polyacrylonitrile nanofibers by solution blow spinning technique for enhanced photocatalytic activity by visible light

AbstractA novel photocatalyst, nano‐sized zinc and cobalt phthalocyanines (MPc), are anchored on polyacrylonitrile (PAN) nanofibers in the presence or absence of TiO2 and the process was realized with an innovative solution blow spinning (SBS) method for the first time. Novel nanofiber composites were characterized by scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy techniques. According to the SEM micrographs, the immobilization of nano‐Pcs on the surface of PAN nanofibers was uniform and does not involve agglomeration. The MPc/PAN composite yielded nearly complete degradation of methylene blue (MB) of a highly photocatalytic nature. It was also found that the presence of TiO2 on MPc/PAN composite have no effect on photodegradation of MB. Also, the recycling of new photocatalysts required as little change as possible owing to their macroscopic structure and their flexible nature.

Solution Blow Spinning of Polyvinylidene Fluoride Based Fibers for Energy Harvesting Applications: A Review.

Polyvinylidene fluoride (PVDF)-based piezoelectric materials (PEMs) have found extensive applications in energy harvesting which are being extended consistently to diverse fields requiring strenuous service conditions. Hence, there is a pressing need to mass produce PVDF-based PEMs with the highest possible energy harvesting ability under a given set of conditions. To achieve high yield and efficiency, solution blow spinning (SBS) technique is attracting a lot of interest due to its operational simplicity and high throughput. SBS is arguably still in its infancy when the objective is to mass produce high efficiency PVDF-based PEMs. Therefore, a deeper understanding of the critical parameters regarding design and processing of SBS is essential. The key objective of this review is to critically analyze the key aspects of SBS to produce high efficiency PVDF-based PEMs. As piezoelectric properties of neat PVDF are not intrinsically much significant, various additives are commonly incorporated to enhance its piezoelectricity. Therefore, PVDF-based copolymers and nanocomposites are also included in this review. We discuss both theoretical and experimental results regarding SBS process parameters such as solvents, dissolution methods, feed rate, viscosity, air pressure and velocity, and nozzle design. Morphological features and mechanical properties of PVDF-based nanofibers were also discussed and important applications have been presented. For completeness, key findings from electrospinning were also included. At the end, some insights are given to better direct the efforts in the field of PVDF-based PEMs using SBS technique.

Solution Blow Spinning Poly(vinyl alcohol) Sub-microfibers Produced from Different Solvents

Poly (vinyl alcohol) (PVA) presents a good chemical stability at room temperature, and interesting physical and mechanical properties that enable a wide range of applications of this material. The relationship between the type of polymer-solvent interaction and the physical properties of the gel can be considered, as a key factor to produce PVA micro- and nanofibers by solution blow spinning (SBS) technique. In this work, the influence of changes in the polymer-solvent interaction as a function of the solvent composition on SBS fiber formation are presented. The low molecular weight PVA solutions were obtained by dissolving the PVA in deionized water, and then adding a more volatile solvent to adjust the final concentration at 0.08 g/mL. The addition of different solvents was performed to modify the chemical nature of the solvent and consequently the polymer-solvent interaction. The viscosity measurements were performed as a function of temperature and shear rate. The rheological characterization of the solutions revealed significant changes in the viscosity value as a function of the solvent nature, although the solution´s rheological behavior showed no significative changes. Finally, the solutions showed potential to produce homogeneous PVA sub-microfibers by solution blow spinning technique. DOI: http://dx.doi.org/10.17807/orbital.v12i1.1169

Halochromic Polystyrene Nanofibers Obtained by Solution Blow Spinning for Wine pH Sensing.

Colorimetric sensors developed by the solution blow spinning (SBS) technique have a rapid response to a variation in different physicochemical properties. In this study, polystyrene nanofibrous (PSNF) mats containing the bromothymol blue (BTB) indicator were obtained by SBS for the pH sensing of wine sample. The incorporation of the indicator did not promote changes in fiber diameter but led to the appearance of beads, allowing for the encapsulation of BTB. The halochromic property of BTB was retained in the PSNF material, and the migration tests showed that the indicator mats presented values below the maximum acceptable limit (10 mg dm−2) established by EU Commission Regulation No. 10/2011 for foods with an alcohol content up to 20%. The present study opens the possibility of applying nanostructured materials to innovative food packaging which, through nanosensory zones, change color as a function of the food pH.

Solution blow spun nickel oxide/carbon nanocomposite hollow fibres as an efficient oxygen evolution reaction electrocatalyst

The development of efficient electrocatalysts for slow reaction of the oxygen evolution reaction (OER) is fundamental for viability of the electrochemical water splitting technologies. Here we report for the first time the synthesis of NiO/carbon hollow fibres (NiO-HF) by the Solution Blow Spinning (SBS) technique, and a study of their catalytic activity towards the OER in alkaline medium. The hollow fibres were obtained with ca. 300 nm in diameter consisting of agglomerated NiO nanoparticles with an average size of 50 nm which is close to the tubular wall thickness. The formation mechanism of the hollow structure was discussed. It was revealed that the carbon from polyenic branch of polyvinylpyrrolidone (PVP) resists the firing treatment and acts as an agglomerating agent, thus ensuring a conductive and percolating path between NiO nanoparticles along the fibres. A battery of electrochemical tests of NiO-HF supported by commercial Ni foam reveals excellent electrochemical activity for OER in 1 M KOH, in comparison with reference NiO nanoparticles (NiO-NP, diameter ca. 23 nm). NiO-HF attains an overpotential of 340 mV vs. RHE at a current density of 10 mA cm−2, which is amongst the lowest values reported in the literature for undoped NiO. Chronopotentiometry reveals stable NiO-HF electrodes over 15 h under an electrolysis current of 25 mA cm−2. Microscopic analysis shows that the fibrillar morphology is completely preserved after the electrolysis test. The remarkable performance of the NiO-HF catalyst is ascribed to the enhanced electronic conductivity resulting from the interpenetrating NiO-HF/carbon microstructure.

Antimicrobial coatings based on poly(dimethyl siloxane) and silver nanoparticles by solution blow spraying

Antimicrobial coatings of poly(dimethyl siloxane) with silver nanoparticles (PDMS/AgNPs) were produced by solution blow spraying (SBSp), an adaptation of the solution blow spinning technique (SBS). Firstly, AgNPs were synthesized by the Turkevich method and characterized by dynamic light scattering (DLS), ultraviolet-visible spectroscopy (UV–vis), agar disk diffusion tests against Escherichia coli and Staphylococcus aureus, and toxicity to Artemia salina. Further, the PDMS/AgNPs coating was prepared in two steps by deposition of PDMS solution in hexane (2:1) over the substrate, and then, five depositions, in intervals of 7.5 min each, of the colloidal dispersion of AgNPs onto partially cured PDMS surface. The neat PDMS and PDMS/AgNPs coatings were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic force microscopy (AFM), contact angle and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS). Furthermore, the antimicrobial activity against S. aureus and E. coli biofilm formation was evaluated by fluorescence. The results indicate that AgNPs were adhered near the PDMS coating surface, assuring antimicrobial activity against the studied microorganisms at a concentration of about 0.04 μg cm−2 and average particle size of 170.5 nm. Therefore, the SBSp technique, used to produce PDMS/AgNPs coating in two steps, proved to be a suitable method to produce antimicrobial coatings with potential applications in active packaging and self-disinfecting surfaces.

Solution blow spinning control of morphology and production rate of complex superconducting YBa2Cu3O7−x nanowires

The demand for nanostructured materials can increase exponentially due to the miniaturization of devices and their potential application in different areas, such as electronic and medicine. Therefore, high production rates are essential for making nanomaterials commercially available. When electrospinning (ES) and solution blow spinning (SBS) are employed for producing ceramic nanostructures, the solution injection rate can influence the morphology without, however, supply the real ceramic production rate. In this work, complex superconducting YBa2Cu3O7-x wires were prepared by using the SBS technique. We also show that the morphology can be controlled by varying the injection rate of the polymer solution and the production rate is 4.7 to 33 times higher than the rates of equivalent ceramics produced by ES. Additionally, we also suggest the term Ceramic Production Rate to refer to the production rate of ceramic structures.

Integrated Polymer Dissolution and Solution Blow Spinning Coupled with Solvent Recovery for Expanded Polystyrene Recycling

With increasing buoyant plastic wastes entering into oceans and food chains, the disposal and recycling of waste expanded polystyrene (WPS) has become an imminent environmental problem. In this work, a recycling scheme for waste WPS is proposed that combines the polymer dissolution recycling approach with the solution blow spinning (SBS) technique that facilitates the high-volume bulk WPS transportation and the value-addition of WPS to nanofibers. Solvent selection is critical for an economical and environmentally favorable implementation of this recycling scheme at large scale. Here, the effect of three solvents with distinct volatility, viz. ethyl acetate, toluene, and N, N- dimethylformamide (DMF) have been studied on the fiber formation and the ease of the solvent recovery, in order to ascertain the practicability of using these solvents for the recycling process. The fiber formation is experimentally demonstrated for the WPS-solvent systems using the SBS process. It is found that the fiber morphology varies for the different WPS-solvent systems. A solvent recovery scheme to recover the solvent from the air-solvent mixture (leaving SBS) is evaluated using ASPEN Plus simulation. The % solvent recovery is determined as a function of the required energy input for different process parameters including compressor pressure and air to polymer solution feed ratio. The simulation studies show that a lower feed air to polymer solution ratio and higher compressor pressure are required to obtain > 70% solvent recovery for high volatility solvents (ethyl acetate and toluene) with lower energy input and optimal operating condenser temperature (~ 0 °C). Conversely, significant solvent losses occur in the SBS process with a lower volatility solvent (DMF), leading to a lower solvent recovery for the whole process. The % DMF recovery can be improved upon by using higher feed air to polymer solution ratio although at a higher energy penalty.

Conductive Nonwoven Carbon Nanotube-PLA Composite Nanofibers Towards Wound Sensors via Solution Blow Spinning.

This paper characterizes the use of the emerging solution blow spinning technique to create conductive carbon nanotube-PLA composite nanofibers. Poly(lactic acid) (PLA) and multi-walled carbon nanotubes (MWCNT) were combined in various solvents to produce conductive fiber mats. In addition, the authors were able to tune the conductivity of the fiber mats by modifying the MWCNT concentration. Conductive fiber mats were able to reach conductivity values as high as 474 S/cm which is more than 2 × higher than the ubiquitous germanium. Conductive fiber mats will be later used as sensors in wound healing applications. A simple light emitting diode circuit featuring the fiber mat was developed as a proof of concept toward this biomedical sensing application.

Preparation and Characterization of Polymeric Microfibers of PLGA and PLGA/PPy Composite Fabricated by Solution Blow Spinning

In this study, microfibers of poly(L‐lactic‐co‐glycolic acid) (PLGA) and PLGA/polypyrrole (PPy) composite (90/10 wt%) are produced by using the solution blow spinning (SBS) technique. PPy is synthesized by the oxidative polymerization method using p‐toluenesulfonic acid (p‐TSA) as the dopant and FeCl3 as the oxidant. The prepared PPy showed microfibers with globular particles morphology. Mixtures of porous and nonporous microfibers and microfibers incorporated with PPy are obtained. A wettability test shows that the PLGA and PLGA/PPy fibrous mats are hydrophobic. The electrical conductivity of the PLGA/PPy composite is of the same order as that of pure PLGA (≈10−10 S cm−1), indicating that the electrical percolation threshold is not reached for PPy loading of 10 wt%. The incorporation of PPy into PLGA microfibers improved the thermal stability of the composite and also increases the PLGA crystalline phase.

1D hollow MFe2O4 (M = Cu, Co, Ni) fibers by Solution Blow Spinning for oxygen evolution reaction

The development of low-cost transition metal electrocatalysts for the oxygen evolution reaction (OER) has been the focus of intense research. Herein, we report for the first time the synthesis of one dimensional (1D) hollow MFe2O4 (M = Cu, Co and Ni) fibers by the Solution Blow Spinning (SBS) technique and their performance towards OER in alkaline medium. The formation mechanism of the hollow structure and the influence of the fibrillar morphology on the performance of electrocatalysts were discussed. Electrocatalytic performance to generate 10 mA cm−2 with low overpotential followed the sequence: CuFe2O4 > CoFe2O4 > NiFe2O4. The improved OER performance of hollow CuFe2O4 fibers is due to a superior number of active sites exposed to surface reactions, confirmed by a remarkable electrochemically active surface area (ECSA) of 225 cm2. Solution blow spun hollow ferrite fibers showed better electrocatalytic activity towards OER than 1D, 2D and 3D ferrite-based nanostructures reported in the literature.

Fabrication of Fish Gelatin Microfibrous Mats by Solution Blow Spinning

In this work microfiber mats of Nile tilapia (Oreochromis niloticus) gelatin were successfully fabricated by using Solution Blow Spinning technique. The concentration and viscosity of fish gelatin solution, in acid acetic/water (80% v/v), were correleted to the morphology and diameter of the gelatin microfibers. It was found that increased solution viscosity leads to increase of fibers diameters from approximately 280 nm at viscosity ~ 0.085 Pa.s. to approximately 1195 nm at viscosity ~ 1.877 Pa.s. The TG thermograms showed similar thermal profiles for all fibrous mat gelatins with thermal stability at temperatures below 180°C. The DSC curve showed two endothermic peaks being the second one, in the range of 100-130°C, strongly influenced by the microfiber diameters. It shifts to higher temperature increasing the microfiber diameter. This behavior was associated to the diffusion of water in the microfibers. Combined DSC/TG results showed a significant influence of the microfiber diameter on the water absorption and desorption process.