Solution Blow Spinning Research Articles

Nanofibrous Polymeric Membranes for Air Filtration Application: A Review of Progress after the COVID‐19 Pandemic

AbstractAir pollution is one of the major global problems causing around 7 million dead per year. In fact, a connection between infectious disease transmission, including COVID‐19, and air pollution has been proved: COVID‐19 consequences on human health are found to be more severe in areas characterized by high levels of particulate matter (PM). Therefore, after the COVID‐19 pandemic, the production of air filtration devices with high filtration efficiency has gained more and more attention. Herein, a review of the post‐COVID‐19 pandemic progress in nanofibrous polymeric membranes for air filtration is provided. First, a brief discussion on the different types of filtration mechanism and the key parameters of air filtration is proposed. The materials recently used for the production of nanofibrous filter membranes are presented, distinguishing between non‐biodegradable polymeric materials and biodegradable ones. Subsequently, production technique proposed for the fabrication of nanofibrous membranes, i.e., electrospinning and solution blow spinning, are presented aiming to analyze and compare filtration efficiency, pressure drop, reusability and durability of the different polymeric system processed with different techniques. Finally, present challenges and future perspectives of nanofibrous polymeric membranes for air filtration are discussed with a particular emphasis on strategies to produce greener and more performant devices.

Flexible piezoelectric PVDF/TPU nanofibrous membranes produced by solution blow spinning

Poly (vinylidene fluoride) (PVDF) nanofibers have been applied in producing piezoelectric membranes for energy harvesting in wearable devices under strenuous service conditions due to its outstanding properties such as piezoelectricity, flexibility, stability, and biocompatibility. Therefore, a processing technique with mass production capability and generating the highest possible piezoelectric properties of PVDF nanofibers is required. To achieve such requirements, this study presented a novel flexible piezoelectric membrane based on PVDF/TPU nanofibers using solution blow spinning (SBS). The addition of TPU into PVDF has been proven to increase the flexibility of the polymeric membranes. The produced membranes showed high piezoelectric response and sensitivity compared to other PVDF-based membranes in the literature especially at 5wt.% TPU concentration, owing to its small nanofiber diameter, high β fraction, and inducing reorientation of electric dipoles. The addition of TPU also significantly enhanced tensile strength and elasticity of the produced membranes. Based on those, this work has shown a promising method to produce high elastic-piezoelectric nanofibrous membrane using SBS.

Effect of chemically modified lignin addition on the physicochemical properties of PCL nanofibers

In this study, a chemically modified lignin additive was successfully prepared to improve the physicochemical properties of biodegradable polycaprolactone (PCL)-based nanofibers. The molecular weight and surface functional group characteristics of lignin were effectively controlled through a solvent fractionation process using ethanol. Then, PCL-g-lignin was successfully synthesized by using ethanol-fractionated lignin as a platform for the PCL grafting process. Finally, PCL/PCL-g-lignin composite nanofibers were simply prepared by adding PCL-g-lignin to the PCL doping solution and performing a solution blow spinning process. The addition of PCL-g-lignin could dramatically improve the physical and chemical properties of PCL nanofibers, and in particular, the tensile strength (0.28 MPa) increased by approximately 280 % compared to the conventional PCL. In addition, the lignin moiety present in PCL-g-lignin was able to impart UV blocking properties to PCL nanofibers, and as a result, it was possible to effectively suppress the photolysis phenomenon that occurred rapidly in existing PCL nanofibers. Therefore, PCL-g-lignin may be widely used not only as a reinforcing agent of existing biodegradable nanofibers but also as a functional additive for UV protection.

Fabrication and magnetic properties of SiO2 nanoparticles-doped BSCCO superconducting nanofibers by solution blow spinning

In this work, the magnetic properties of Bi2Sr2CaCu2O8+θ (BSCCO) superconducting nanofibers prepared by solution blow spinning technology were studied systematically. The BSCCO superconductors were doped with SiO2 nanoparticles in order to study the influence of non-superconducting impurities on the microstructure and magnetic properties of superconductors. The results showed that 0.2 wt% SiO2 nanoparticles can improve superconducting performance as efficient magnetic flux pinning centers in BSCCO superconductors. For examples the superconducting transition temperature was increased from 76.5 K to 80.3 K, the critical current density was increased from 0.68 × 108 A m−2 to 1.43 × 108 A m−2, and the pinning strength was increased from 4.4 × 107 N m−3 to 8.1 × 107 N m−3. In addition, it was found that appropriate amount of SiO2 nanoparticles can improve the size of superconducting grains and enhance the connectivity of superconducting grains. Moreover, the pinning mechanism of each sample demonstrated that SiO2 nanoparticles improved the pinning performance of BSCCO. Furthermore, this is the first report on the BSCCO superconductors that doped with SiO2 nanoparticles.

Green preparation of electrically conductive solution blow spun nanofibers from recycled polyethylene terephthalate via plasma-assisted oxidation-reduction.

Simple and green strategy was described for the development of multifunctional polyester nanofibers (PNFs). Solution blow spinning (SBS) technology was applied to in situ immobilize nanocomposites of polyaniline (PANi) and silver nanoparticles (AgNPs) into plasma-treated polyester nanoscaled fibers prepared. The polyester nanofibers were prepared from recycled polyethylene terephthalate waste, which was exposed plasma-curing and a REDOX reaction in the presence of AgNO3, aniline, and CH3COONH4. Plasma-catalyzed oxidative polymerization of aniline to polyaniline together with a reductive process of Ag+ to silver nanoparticles led to their enduring insoluble dispersion into the surface of polyester nanofibers. By taking the advantage of the PANi oxidation, AgNPs were precipitated from an aqueous medium of AgNPs. The morphological properties were investigated by various analytical techniques. The polyester fiber diameter was determined in the range of 450-650nm. In addition, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were utilized to examine AgNPs, demonstrating diameters of 4-20nm. The plasma-uncured AgNPs/PANi immobilized nanofibrous film displayed weak absorption bands at 399nm and 403nm upon increasing the concentration of AgNPs. On the other hand, the plasma-cured AgNPs/PANi immobilized nanofibers displayed strong absorption bands at 526nm and 568nm upon increasing the concentration of AgNPs. The AgNP-induced antimicrobial performance and the PANi-induced electrically conductivity were explored. The prepared PNFs showed high UV protection.

Multilayered blow-spun vascular prostheses with luminal surfaces in Nano/Micro range: the influence on endothelial cell and platelet adhesion

BackgroundIn this study, two types of polyurethane-based cylindrical multilayered grafts with internal diameters ≤ 6 mm were produced by the solution blow spinning (SBS) method. The main aim was to create layered-wall prostheses differing in their luminal surface morphology. Changing the SBS process parameters, i.e. working distance, rotational speed, volume, and concentration of the polymer solution allowed to obtain structures with the required morphologies. The first type of prostheses, termed Nano, possessed nanofibrous luminal surface, and the second type, Micro, presented morphologically diverse luminal surface, with both solid and microfibrous areas.ResultsThe results of mechanical tests confirmed that designed prostheses had high flexibility (Young’s modulus value of about 2.5 MPa) and good tensile strength (maximum axial load value of about 60 N), which meet the requirements for vascular prostheses. The influence of the luminal surface morphology on platelet adhesion and the attachment of endothelial cells was investigated. Both surfaces did not cause hemolysis in contact with blood, the percentage of platelet-occupied area for Nano and Micro surfaces was comparable to reference polytetrafluoroethylene (PTFE) surface. However, the change in morphology of surface-adhered platelets between Nano and Micro surfaces was visible, which might suggest differences in their activation level. Endothelial coverage after 1, 3, and 7 days of culture on flat samples (2D model) was higher on Nano prostheses as compared with Micro scaffolds. However, this effect was not seen in 3D culture, where cylindrical prostheses were colonized using magnetic seeding method.ConclusionsWe conclude the produced scaffolds meet the material and mechanical requirements for vascular prostheses. However, changing the morphology without changing the chemical modification of the luminal surface is not sufficient to achieve the appropriate effectiveness of endothelialization in the 3D model.

Controlled Release of a Therapeutic Peptide in Sprayable Surgical Sealant for Prevention of Postoperative Abdominal Adhesions.

Formation of asymmetric, rigid scar tissue known as surgical adhesions is caused by traumatic disruption of mesothelial-lined surfaces in surgery. A widely adopted prophylactic barrier material (Seprafilm) for the treatment of intra-abdominal adhesions is applied operatively as a pre-dried hydrogel sheet but has reduced translational efficacy due its brittle mechanical properties. Topically administered peritoneal dialysate (Icodextrin) and anti-inflammatory drugs have failed to prevent adhesions due to an uncontrolled release profile. Hence, inclusion of a targeted therapeutic into a solid barrier host matrix with improved mechanical properties could provide dual utility in adhesion prevention and as a surgical sealant. Spray deposition of poly(lactide-co-caprolactone) (PLCL) polymer fibers through solution blow spinning has yielded a tissue-adherent barrier material with previously reported adhesion prevention efficacy due to a surface erosion mechanism that inhibits deposition of inflamed tissue. However, such an approach uniquely presents an avenue for controlled therapeutic release through mechanisms of diffusion and degradation. Such a rate is kinetically tuned via facile blending of "high" molecular weight (HMW) and "low" molecular weight (LMW) PLCL with slow and fast biodegradation rates, respectively. Here, we explore viscoelastic blends of HMW PLCL (70% w/v) and LMW PLCL (30% w/v) as a host matrix for anti-inflammatory drug delivery. In this work, COG133, an apolipoprotein E (ApoE) mimetic peptide with potent anti-inflammatory properties was selected and tested. In vitro studies with PLCL blends presented low (∼30%) and high (∼80%) percent release profiles over a 14-day period based on the nominal molecular weight of the HMW PLCL component. Two independent mouse models of cecal ligation and cecal anastomosis significantly reduced adhesion severity versus Seprafilm, COG133 liquid suspension, and no treatment control. The synergy of physical and chemical methods in a barrier material with proven preclinical studies highlights the value of COG133-loaded PLCL fiber mats in effectively dampening the formation of severe abdominal adhesions.

Preparation of cellulose acetate film with dual hydrophobic-hydrophilic properties using solution blow spinning

Solution blow spinning (SBS), a processing method alternative to electrospinning, where pressured air is used instead of an electric field, was used in this work for the preparation of cellulose acetate (CA) materials. The sequential use of SBS to produce a double-layered film is also investigated. Mixtures of acetone with acetic acid or N,N-dimethylformamide (DMF) were studied as systems for polymer solution preparation. The type of produced material (flat film or multi-structured membranes constituted from submicrometric fibers with beads), its thermal properties, crystallinity, and morphology are more dependent on the solvent system than other SBS processing parameters. Roughness and porosity of differently produced materials influence wettability measured by the contact angle, which ranges in this work from approx. 69.8° ± 3° for a flat film to 104° ± 5° for fibrous material. Finally, a double-layered film, prepared by sequential SBS of individual layers different in terms of wettability, renders a standalone film of dual wettability, with one side hydrophobic and the other hydrophilic.

An experimental design approach to examine the influencing parameters of poly(butylene succinate) (PBS) nanofibrous nonwoven by solution blow spinning

Green polymers have gained popularity in recent decades because of the rising pollution in the world. Poly(butylene succinate) (PBS) is an aliphatic polyester and a relatively new polymer. PBS is regarded as one of the most promising materials for various applications due to its exceptional processability and regulated biodegradability and attracts the attention of many researchers. The application fields of its products when combined with the solution blow spinning (SBS) method, may be expanded to textiles, food, packaging, filters, batteries, and biomedical due to its outstanding biodegradability, processability, and thermal and chemical resistance. Therefore, this study focused on the SBS process as a PBS polymer solution to scale up the nanofibers manufacturing process to the commercial level. In this research, PBS nonwovens were produced by an SBS apparatus. The effects of spinning parameters (solution concentration, air pressure, and flow rate) on the average fiber diameter were studied. The PBS solution blown nonwovens was characterized by scanning electron microscopy. A software was used to measure fiber diameter and distribution. PBS nonwovens were mostly on a nanometer scale with the presence of a few defects. A full factorial design was used to the test data for statistical analysis to investigate how solution concentration, air pressure, and flow rate influenced average fiber diameter. The impact of process control factors is examined using analysis of variance. Results have shown that solution concentration significantly influenced of mean diameter. The fast and economic feature of the SBS process, as well as the environmentally friendly nature of the PBS polymer, may considerably contribute to the industrial-scale manufacturing of nanofibrous nonwoven made from this polymer.

Gas-assisted electrospinning of high-performance ceramic fibers: Optimal design modelling and experimental results of the gas channel of the nozzle

Electrospinning (ES) of ceramic fibers has mostly remained in the research level, which can be because of the hard process and parameters controlling the low rate of production. The yield of fiber production by solution blow spinning (SBS) is exciting but the production process is unstable due to the reverse flow phenomenon. In this paper, we prepared high-performance ceramic fibers by gas-assisted electrospinning (GES), which combined the advantages of ES and SBS. Also, comprehensive numerical and experimental analysis for nanofibers produced using GES are provided. The gas flow characteristics through different parameters' nozzle were investigated numerically using computational fluid dynamics and experimentally in a custom-built gas-assisted electrospinning setup to produce SiO2 nanofibers.

Release Profiles of Carvacrol or Chlorhexidine of PLA/Graphene Nanoplatelets Membranes Prepared Using Electrospinning and Solution Blow Spinning: A Comparative Study

Nanofibrous membranes are often the core components used to produce devices for a controlled release and are frequently prepared by electrospinning (ES). However, ES requires high production times and costs and is not easy to scale. Recently, solution blow spinning (SBS) has been proposed as an alternative technique for the production of nanofibrous membranes. In this study, a comparison between these two techniques is proposed. Poly (lactic acid)-based nanofibrous membranes were produced by electrospinning (ES) and solution blow spinning (SBS) in order to evaluate the different effect of liquid (carvacrol, CRV) or solid (chlorhexidine, CHX) molecules addition on the morphology, structural properties, and release behavior. The outcomes revealed that both ES and SBS nanofibrous mat allowed for obtaining a controlled release up to 500 h. In detail, the lower wettability of the SBS system allowed for slowing down the CRV release kinetics, compared to the one obtained for ES membranes. On the contrary, with SBS, a faster CHX release can be obtained due to its more hydrophilic behavior. Further, the addition of graphene nanoplatelets (GNP) led to a decrease in wettability and allowed for a slowing down of the release kinetics in the whole of the systems.

Biomedical Applications of Blow-Spun Coatings, Mats, and Scaffolds—A Mini-Review

Human tissues and disease models require well-defined biomimetic microenvironments. During the past decade, innovative developments in materials science, microfabrication, and polymer science have provided us with the ability to manipulate cellular microenvironments for regenerative medicine and tissue engineering applications. Solution blow spinning is a facile fiber fabricating method that requires a simple apparatus, a concentrated polymer solution within a volatile solvent, and a high-pressure gas source. Commercially available airbrushes, typically used for painting and cosmetic makeup, have successfully generated a range of nanofibers and films. Applications under investigation are similar to electrospinning and include enzyme immobilization, drug delivery, filtration, infection protection, tissue engineering, and wound healing. This review will discuss fiber fabrication methods before a more detailed discussion of the potential of blow-spinning in biomedical applications.

Electrically-assisted supersonic solution blowing and solution blow spinning of fibrous materials from natural rubber extracted from havea brasilienses

Natural rubber (NR) is one of the most-studied natural polymers in the world due to its inherent characteristics and excellent properties. This renewable polymer has been used in industrial production of a wide range of products, from aircraft tires to medical devices. In the present study two novel methods of NR fibrous mat formation are investigated and compared: the electrically-assisted supersonic solution blow technique (EASBS) and solution blow spinning (SBS). The influence of processing parameters on the formation, morphology, and physical properties of the NR fibers is explored using scanning electron microscopy (SEM), mechanical testing, mechanical dynamic analysis (DMA), and thermal analysis (DSC and TG/DTG). Furthermore, the effect of 10% phenolic resin (PHOH) admixture on the final properties of NR obtained by EASBS, SBS and films formed by casting was investigated. SEM analysis helped to optimize the production conditions for NR and NR-PHOH fibrous mats by both EASBS and SBS with a fiber diameter in the 2–4 µm and 20–40 µm ranges, respectively. As a result of a more uniform distribution of NR fibers forming soldering points, the EASBS specimens appeared to be stiffer than those obtained by SBS and casting, resulting in a lower strain and a higher stress at break. TG/DTG analysis revealed that the thermal profiles were the same for all specimens, with polyisoprene decomposition occurring between 350 and 450 °C, whereas the Raman spectrum revealed that the bands for NR and PHOH resin were superimposed, indicating that there is no chemical interaction between the materials. Overall, NR fibrous mats with and without PHOH formed via EASBS and SBS revealed good mechanical properties as well as thermal stability.

Obtaining poly (lactic acid) nanofibers encapsulated with peppermint essential oil as potential packaging via solution-blow-spinning

The development of active packaging based on biodegradable material and incorporating active compounds, such as essential oil, is a new technique to ensure food safety without harming the environment. In this study, nanofiber mats of poly (lactic acid)/ polyethylene glycol (PLA/PEG) blend incorporated with peppermint essential oil (PO) at different ratios (5–20 % v/w) were produced by solution-blow-spinning (SBS) for potential packaging application. Electron microscopy showed a cylindrical and interlaced morphology for PLA/PEG/PO and a significant increase in the diameter (139–192 nm) of the nanofibers by increasing PO content. All nanofibers showed high thermal stability (278–345 °C) suitable for use in the food industry. Nuclear magnetic resonance (13C NMR) spectrum confirmed PO in the nanofibers after SBS. ATR-FTIR spectral analysis supported the chemical composition of the nanofiber mats. PO addition led to obtaining hydrophobic nanofibers, enhancing the contact angle to 122° and decreasing water vapor permeability (60 % reduction compared to the PLA/PEG (3.0 g.mm.kPa−1.h−1.m−2). Although the PLA/PEG/20%PO nanofibers did not show halo formation in 24 h, they effectively extended the strawberries' shelf-life at 25 °C, evidencing PO release over time. It also reduced weight loss (2.5 % and 0.3 % weight loss after 5 days for PLA/PEG and PLA/PEG/20%PO, respectively) and increased firmness (8–12 N) for strawberries packed with the nanofiber mats. It is suggested that PLA/PEG films incorporating PO may be used as an active, environmentally friendly packaging material.

Engineering of Nb2O5 sub-micrometric fibers from metal oxide precursor nanoparticles by Solution Blow Spinning

Niobium pentoxide (Nb2O5) sub-micrometric fibers were produced by Solution Blow Spinning (SBS) from oxide nanoparticles as starting material dispersed in polymer solutions used as a spinning aid. It was observed that the thermo-physical properties of poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) significantly influenced the consolidation of the fibrillar morphology after thermal treatment by calcination. However, the nanometric size of the oxide particles plays the leading role due to the kinetics of neck formation during sintering, according to the molecular dynamic simulations, being up to five orders of magnitude more efficient for nanoparticles of 6.5 nm in size. This work demonstrates the proof of concept of engineering metal-oxide fibers directly from nanopowder oxides used as precursors.

Characterization of Solution Blow Spun Poly(Lactic) Acid Based Nanofibers Containing Sucuk Spice Mix Essential Oils

In this study, essential oil (EO) from sucuk spice mix was incorporated into poly(lactic) acid (PLA) and nanofibers were produced via solution blow spinning (SBS). EO incorporation was performed at 0, 5, 10, 15, 20, 25, and 30% (v/w) of PLA. Mechanical, barrier, microstructural, topographical, contact angle, chemical, thermal, antioxidant, and antibacterial properties against E. coli and S. aureus were characterized. Nanofibers were not soluble in water due to the hydrophobic nature of PLA. Microstructural images revealed that beadles and uniform nanofibers can be produced with SBS, and EO addition decreased the average fiber diameter. The surface topography of nanofibers was improved by increasing EO concentration. Melting and glass transition temperatures decreased and the thermal stability of nanofibers increased with EO addition. Nanofibers containing EO at 30% had the highest antioxidant capacity (40.02%). Nanofibers containing 20, 25, and 30% of EO had greater growth inhibition against Staphylococcus aureus and Escherichia coli. As a result, PLA-based nanofibers containing sucuk spice mix EO can be produced with SBS, and nanofibers containing 20, 25, and 30% EO could be a promising system not only in drug delivery systems but also in food packaging.

Preparation of covalent organic framework-based nanofibrous films with temperature-responsive release of thymol for active food packaging

Thymol (THY) is commonly used in active food packaging, however because of its high volatility, poor water solubility, and strong aromatic odor, the application of THY is facing challenges. Herein, covalent organic frameworks (COFs) were synthesized in room temperature by asymmetric monomer exchange method for THY encapsulation, and solution blow spinning was used to fabricate the THY@COF/polycaprolactone (PCL) nanofibrous films. The synthesized COFs had a large specific surface area, porous structure, and loading capacity of 30.35% for THY, and THY@COFs possessed good thermal stability. Characterization analysis showed that THY@COFs were successfully incorporated into the PCL films and increased the barrier property of the films. Besides, the films showed good biocompatibility and antibacterial activity. Moreover, THY@COF/PCL films exhibited temperature-responsive THY release profiles, which is important for practical preservation applications, especially for preserving food in warm environments. Overall, THY@COF/PCL films possess promising potential in active food packaging.

Morphological and biochemical analysis of cells cultured on fibrous poly(ε-caprolactone) scaffolds with different degrees of fiber alignment produced by solution blow spinning.

Bioresorbable materials are compounds that decompose in physiological mediums both in vitro and in vivo and are used as an alternative to temporary implants in injured tissues. The aim of this study was to analyze the morphology and cytochemistry of cells grown on fibrous poly(ε-caprolactone) (PCL) scaffolds and to measure cell metabolism parameters by biochemical analysis of the conditioned culture medium from cells grown on the scaffolds. Fibrous PCL scaffolds were used under the following conditions: unaligned fibers (NA), fibers aligned at 150 rpm (A150), and fibers aligned at 300 rpm (A300). Vero cells were cultured on these scaffolds for 24 h, 48 h, and 72 h. Samples were analyzed by SEM, MicroCT, cytochemistry, and culture medium biochemistry. The results of the cytochemical analysis showed cells were confluent and well spread on the culture plate, while cells grown on the polymeric scaffold, exhibited an elongated morphology. In the biochemical analyses, no significant differences were observed in the expression of alkaline phosphatase or in the levels of cholesterol or total protein in the culture medium. The different materials do not seem to promote changes in the expression or metabolism of these molecules. Only glucose was markedly reduced in the culture medium of cells grown on either aligned or unaligned scaffolds for 48 h or 72 h. This finding indicates the intense energy requirements of cells grown on these scaffolds. PCL fibers showed a great capacity to support cell growth. These data reinforce the interpretation that cells grow satisfactorily on PCL scaffolds.

PVDF/MWCNT nanocomposites with complex configurations prepared by solution blow spinning and their flexoelectric responses

A study of flexoelectric behavior of polyvinylfluoride, PVDF-based materials, was carried out considering the design in macroscopic terms. The materials are prepared using solution blow spinning (SBS) manufacturing multilayers of PVDF filled with multi-walled carbon nanotubes (MWCNT) with good control of concentration. Flexoelectric behavior of the materials is studied with a testing machine of our own design to obtain output voltage signals under cyclic mechanical perturbation as a function of perturbation rate. Mechanical behavior of the materials is described as a function of their porosity and MWCNT concentration. It is demonstrated that flexoelectricity does not only depend on the strain gradient but also on the time of mechanical response of the materials or their viscoelastic properties. This work offers a new insight on the study of flexoelectric behavior of polymer composite materials and how designing PVDF-based materials with high flexoelectric yields and, therefore, with high potentiality to be used as easy-to-handle sensors.

Effects of Processing Variables on the Morphology and Microstructural Characteristics of TiO2 Fibers Produced by Solution Blow Spinning

Effects of Processing Variables on the Morphology and Microstructural Characteristics of TiO2 Fibers Produced by Solution Blow Spinning