Production Of Nanofibers Research Articles

Olive pomace upcycling: Eco-friendly production of cellulose nanofibers by enzymatic hydrolysis and application in starch films.

Olive pomace (OP) waste, produced in large quantities, contains significant amounts of cellulose and fibers, making it a valuable resource for developing reinforcing ingredients in biodegradable packaging materials. This study aimed to produce nanofibers from OP using enzymatic hydrolysis with hemicellulases and cellulases, and to incorporate these nanofibers into starch films as a reinforcing agent. Cellulose nanofibers (CNFs) were prepared by alkaline pretreatment followed by enzymatic hydrolysis (with hemicellulases and cellulases) from olive pomace and applied as reinforcement in starch films in concentrations of 0.5%-5% (w/v). The nanofibers were analyzed according to composition, structural, and thermal properties. The nanofibers' suspension presented a cloudy and white color in aqueous suspension, the X-ray diffraction (XRD) analysis showed the increase of crystallinity, and the fibers' range was no wider than 100nm (according to Scherer equation). The composition analysis showed the decrease of carbonyl groups of hemicellulose and lignin. The starch films presented a homogenous surface. The solubility from these biodegradable films significantly reduced after the incorporation of CNF, and the nanomaterial's presence improved the degradation temperature (from 310°C to 322°C) and the mechanical resistance because the tension of rupture increased from 3.79 to 6.21MPa. PRACTICAL APPLICATION: The utilization of waste from the olive pomace for cellulose nanofiber production holds promise, given the nanofibers' ability to readily integrate into various materials, including starches used in biodegradable film production. Within these matrices, nanofibers act as structure reinforcers and significantly reduce the solubility of films. Although biodegradable films ensure the shelf life, safety, and quality of food, their properties currently do not match those of traditional petroleum-based materials at an industrial scale, indicating a need for further enhancement.

Cent-Hydro: A Novel Temperature and Pressure-Controlled Hybrid System for Large-Scale Nanofiber Production

The present study aimed to develop a novel temperature and pressure-controlled hybrid system (Cent-Hydro) for large-scale nanofiber production. Nanofibers from a hydrophilic carrier matrix were prepared using the Cent-Hydro system. This study explores the effect of increasing working temperature on the surface tension and viscosity of polymer solutions. The Cent-Hydro system was calibrated through the process of jet formation, and spinning parameters were identified for the jet path. The formation of fingers in front of the thin liquid occurred due to Rayleigh–Taylor instability, and a lower concentration of polymer solution favoured the development of thinner and longer fingers. The critical angular velocity and initial velocity for jet formation were obtained when the balance between surface tension, centrifugal force, and viscous force was achieved. The effect of increasing rotational speed and working temperature on finger velocity and length was experimentally evaluated, concluding that an increase in working temperature increases finger velocity and length. Additionally, the effect of increasing rotational speed, polymer concentration, and working temperature on the diameter of the nanofiber was evaluated. Overall, the Cent-Hydro system presents a compelling proposition for large-scale nanofiber production, offering distinct advantages over conventional methods and paving the way for advancements in various applications.

Effect of catalyst and oxidant concentrations in a TEMPO oxidation system on the production of cellulose nanofibers.

In traditional TEMPO oxidation systems, the high cost of TEMPO catalysts has been a significant barrier to the industrialization of oxidized CNF. From an economic perspective, presenting the characteristics of various CNFs produced with the oxidation systems with reduced catalyst usage could facilitate the industrial application of CNF across a wide range of fields. In this study, it was demonstrated that reducing the amount of TEMPO catalyst used (from 0.1 to 0.05 mmol g-1) in a conventional oxidation system increased the carboxylate content by approximately 6.3%. Furthermore, the activation of hydroxyl amine TEMPO, which is generated after the oxidation reaction of cellulose, was enhanced by adjusting the dosage of the inexpensive oxidant NaClO, leading to a 20% improvement in carboxylate content. This suggests that controlling the amount of NaClO as an oxidant can be a key parameter in adjusting the dosage of TEMPO to achieve the targeted degree of surface substitution. Results from the dispersion stability, UV-transmittance, and morphological properties of TEMPO-oxidized CNF using microfluidizing treatment showed that high carboxylate content plays a crucial role in producing high-purity CNF suspensions, which are small, uniform, and free from microfibers. Additionally, by varying the number of mechanical treatments applied to the oxidized cellulose, various types of CNF suspensions with different mean widths were obtained. We expect that these findings offer meaningful insights to end-users seeking a breakthrough in the performance limitations of final applications using cellulose nanomaterials.

Preparation of Effective NiCrPd-Decorated Carbon Nanofibers Derived from Polyvinylpyrrolidone as a Catalyst for H2 Generation from the Dehydrogenation of NaBH4.

The catalytic dehydrogenation of NaBH4 for the generation of H2 has a lot of potential as a reliable and achievable approach to make H2, which could be used as a safe and cost-effective energy source in the near future. This work describes the production of unique trimetallic NiCrPd-decorated carbon nanofiber (NiCrPd-decorated CNF) catalysts using electrospinning. The catalysts demonstrated exceptional catalytic activity in generating H2 through NaBH4 dehydrogenation. The catalysts were characterized using SEM, XRD, TEM, and TEM-EDX analyses. NiCrPd-decorated CNF formulations have shown higher catalytic activity in the dehydrogenation of NaBH4 compared with NiCr-decorated CNFs. It is likely that the better catalytic performance is because the three metals in the NiCrPd-decorated CNF structure interact with each other. Furthermore, the NiCrPd-decorated CNFs catalyzed the dehydrogenation of NaBH4 with an activation energy (Ea) of 26.55 KJ/mol. The kinetics studies showed that the reaction is first-order dependent on the dose of NiCrPd-decorated CNFs and zero-order dependent on the concentration of NaBH4.

Methods for increasing productivity of AC-electrospinning using weir-electrode

The presented work brings new knowledge in the field of spinning electrodes for AC‑electrospinning technology, which is used for producing nanofibrous structures using a solution of polyvinyl butyral. It presents new types of spinning weir‑electrodes and describes research on the influence of electrode design parameters on the stability of the spinning process and the productivity of nanofiber production. The multistage spinning electrode is presented in the ratio of stages one to five. Research is also focused on the effect of the parameters of the electric signal used as a source for the spinning electrode on spinning stability and productivity. Observed parameters were voltage level, frequency and shape such as sine wave, rectangle wave and modified sine wave. An analysis of the influence of the spinning conditions on the resulting nanofibrous structure was also performed by analyzing results gained by SEM; the defects were investigated mainly. The results of the research presented in the thesis open up new possibilities for follow-up research in the field of AC-electrospinning.

The morphology and thermo-regulating properties of electrospun PVA/PEG/Ag nanofibers of water and formic acid solvents

The solvent utilized in the electrospinning solution significantly impacts the morphology and thermal properties of PVA/PEG/Ag nanofibers. To prevent leakage of PEG, solid-liquid phase change, a suitable encapsulation method involves utilizing a combined single-phase electrospinning that incorporates PEG and supporting polymer of PVA. This study aims to investigate the production of thermal-regulating nanofibers from a solution containing PEG 6000, PVA, and AgNO3 precursor using electrospinning method. The influence of water and formic acid as a solvent on the morphology of the nanofibers was examined using SEM. The selected nanofiber characteristics and thermal performance were evaluated through FE-SEM, FT-IR, XRD, DSC, PCM leakage, and DTG tests. SEM images revealed that the formic acid-based nanofibers, consisting of two polymers and two polymer/Ag NPs, exhibited a nanoporous membrane, possibly due to enhanced cross-linking compared to water-based nanofibers. The results of the DSC indicated that fusion and solidification enthalpies of the selected water-based nanofibers were measured as 70.09 and −85.43 J/g, respectively. Unexpectedly, the DSC results indicated higher enthalpies compared to unheated samples. SEM image after thermal cycles, leakage results, and DTG of water-based nanofibers demonstrated their production with thermal stability, reliability, and the potential for creating shape-stable, thermally regulating fabricated nanofibers for various applications.

Cellulose, cellulose nanofibers, and cellulose acetate from Butia fruits (Butia odorata): Chemical, morphological, structural, and thermal properties

Cellulose possesses numerous advantageous properties and is a precursor to compounds and derivatives. The objective of this study was to isolate and characterize cellulose from Butia fruits and simultaneously produce cellulose nanofibers and cellulose acetate from the isolated cellulose. Cellulose extraction was performed using a combination of alkaline and bleaching treatments, while the production of cellulose nanofibers and cellulose acetate was achieved through acid hydrolysis and acetylation, respectively. The materials were characterized by their chemical composition, size distribution, zeta potential, morphology, relative crystallinity (XRD), functional groups (FTIR), molecular structure (NMR), and thermal stability (TGA). The Butia crude fibers presented 49.4 % cellulose, 4.5 % hemicellulose, 25.4 % lignin, and 1.3 % ash. The cellulose nanofibers presented an average diameter ranging from 13.7 to 93.1 nm and exhibited a high degree of crystallinity (63.3 %). FTIR, XRD, 13C, and 1H NMR analyses confirmed that the isolation processes effectively removed amorphous regions from the cellulose nanofibers and confirmed the cellulose acetylation process. As demonstrated, cellulosic materials derived from Butia fruit exhibit promise for various applications, including their potential use as reinforcing agents in polymer matrices, due to their high extraction yield, thermal properties, and crystallinity.

Challenges Associated with the Production of Nanofibers

Challenges Associated with the Production of Nanofibers

High‐Throughput Production of Gelatin‐Based Touch‐Spun Nanofiber for Biomedical Applications

Nanofiber production techniques have become increasingly important due to their wide range of applications. However, the complex design of the setup and difficulty in scaling up to high production rate have limited the industrial applicability of some of the conventional fiber generation techniques such as electrospinning. Herein, the touch spinning method is scaled up for nanofiber production using a simple rotating drawing setup with polymers that are relevant for biomedical applications such as polyethylene oxide and gelatin. The process is amenable to use of benign solvent such as water and production of a wide variety of submicron‐scale gelatin‐based nanofibers at a high throughput (≈2.45 g hr−1 with the single channel flow), which is an order of magnitude higher than those produced by other fiber generation methods is shown. The parametric study indicates that the fiber production process can be tuned at a desired rate without sacrificing the fiber quality by simply altering the number of drawing rods, the size of the rotating disk, and the number of solution flow supply channels. The utility of this technique for different biomedical applications such as cell culture and air filtration applications is also demonstrated.

Study of the impact of polymeric solution preparation parameters on the production of nanofibers based on PAN and PVA

Study of the impact of polymeric solution preparation parameters on the production of nanofibers based on PAN and PVA

Nanofiber-Based Drug Delivery Systems: A Review on Its Applications, Challenges, and Envisioning Future Perspectives.

Nanomaterials, especially nanofibers, hold considerable promise as drug delivery systems (DDS) by providing targeted administration of drugs due to their unique properties, such as large surface area, high porosity, and mechanical robustness. Nanofibers can be fabricated using various techniques like electrospinning, self-assembly, phase separation, and template synthesis, offering properties such as adjustable size, shape, high precision, and biodegradability. Additionally, features such as multiple target functionalization, controlled release of the drug, and prolonged circulation of the drug make nanofibers particularly suitable for biomedical applications, including drug delivery, tissue regeneration, and biosensing. This comprehensive review explores the characteristics, types, fabrication methods, and applications of nanofibers. Diverse types of polymer nanofibers are used in drug delivery, such as blended nanofibers, core-shell nanofibers, and layer-by-layer assembly, each demonstrating their own advantages in controlled drug release and targeted therapy. Electrospun nanofibers are extensively utilized in biomedical applications due to their superior mechanical performance and high porosity and advancements in coaxial electrospinning enabling the fabrication of core-shell nanofibers, offering controlled drug release kinetics and protection of loaded molecules. These nanofibers demonstrate enhanced bioactivity and biocompatibility and can find application in tissue engineering. Furthermore, this review addresses the challenges associated with nanofiber production, including reproducibility and scalability. Nanofibers exhibit the potential to revolutionize medical treatment across diverse therapeutic areas. Future research directions and challenges in nanofiber-based drug delivery discussed in this review offer guidance for further advancements in this rapidly evolving field.

Advances in the Fabrication, Properties, and Applications of Electrospun PEDOT-Based Conductive Nanofibers.

The production of nanofibers has become a significant area of research due to their unique properties and diverse applications in various fields, such as biomedicine, textiles, energy, and environmental science. Electrospinning, a versatile and scalable technique, has gained considerable attention for its ability to fabricate nanofibers with tailored properties. Among the wide array of conductive polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) has emerged as a promising material due to its exceptional conductivity, environmental stability, and ease of synthesis. The electrospinning of PEDOT-based nanofibers offers tunable electrical and optical properties, making them suitable for applications in organic electronics, energy storage, biomedicine, and wearable technology. This review, with its comprehensive exploration of the fabrication, properties, and applications of PEDOT nanofibers produced via electrospinning, provides a wealth of knowledge and insights into leveraging the full potential of PEDOT nanofibers in next-generation electronic and functional devices by examining recent advancements in the synthesis, functionalization, and post-treatment methods of PEDOT nanofibers. Furthermore, the review identifies current challenges, future directions, and potential strategies to address scalability, reproducibility, stability, and integration into practical devices, offering a comprehensive resource on conductive nanofibers.

Production and characterization of electro-blown nanofibers incorporated with pine pollen for fast-dissolving applications

This study aims to harness the rapid dissolution capability of Polyvinylpyrrolidone (PVP), a versatile and biocompatible polymer, in conjunction with pine pollen, a natural substance rich in antioxidants and offering nutrient-dense advantages for overall health and vitality, for the development of fast-dissolving tablet applications. Employing the electro-blown spinning method, PVP nanofibers were fabricated with pine pollen dust sourced from male pine cones. Through electro-blown spinning (EBS), Polyvinylpyrrolidone (PVP) nanofibrous mats were produced with varying concentrations of Pine pollen (PP) (1,3 and 5 %). Analyses were conducted to assess the characteristics of the produced nanofibers, including morphology, thermal stability, mechanical properties, and surface wettability. Antioxidant tests and α‐glycosidase inhibition activity tests were performed to explore the health benefits of nanofibrous mats. The water solubility of PVP, PVP/1 PP, PVP/3 PP, and PVP/5 PP was measured to be 6.97, 4.74, 3.03, and 6.67 s, respectively. The antioxidant properties and α-glycosidase inhibition activity were preserved in the developed fibers. Notably, the α-glycosidase inhibition activity test demonstrated promising results, suggesting the potential of these fibers in regulating glucose absorption and enhancing glycemic control, highlighting their prospective benefits in diabetes management.

Production of cinnamon essential oil-loaded electrospun nanofiber for postharvest technology application usage

Production of cinnamon essential oil-loaded electrospun nanofiber for postharvest technology application usage

Antibacterial Electrospun Membrane with Hierarchical Bead-on-String Structured Fibres for Wound Infections.

Chronic wounds often result in multiple infections with various kinds of bacteria and uncontrolled wound exudate, resulting in several healthcare issues. Advanced medicated nanofibres prepared by electrospinning have gained much attention for their topical application on infected chronic wounds. The objective of this work is to enhance the critical variables of ciprofloxacin-loaded polycaprolactone-silk sericin (PCL/SS-PVA-CIP) nanofibre production via the process of electrospinning. To examine the antibacterial effectiveness of PCL/SS-PVA-CIP nanocomposites, the material was tested against P. aeruginosa and S. aureus. The combination of PCL/SS-PVA-CIP exhibited potent inhibitory properties, with the most effective concentrations of ciprofloxacin (CIP) being 3 μg/g and 7.0 μg/g for each bacterium, respectively. The biocompatibility was evaluated by conducting cell reduction and proliferation studies using the human epidermal keratinocyte (HaCaT) cells and human gingival fibroblasts (HGFs) in vitro cell lines. The PCL/SS-PVA-CIP showed good cell compatibility with HaCaT and HGF cells, with effective proliferation even at antibiotic doses of up to 7.0 μg/g. The drug release effectiveness of the nanocomposites was assessed at various concentrations of CIP, resulting in a maximum cumulative release of 76.5% and 74.4% after 72 h for CIP concentrations of 3 μg/g and 7 μg/g, respectively. In summary, our study emphasizes the possibility of combining silk sericin (SS) and polycaprolactone (PCL) loading with CIP nanocomposite for wound management.

Preparation and Characterization of Electrospun Ketoconazole Loaded Nanofibers as Dermal Patch

Objective: This study aims to formulate a ketoconazole patch containing electrospun nanofibres and enhance the solubility due to theincreased particle surface using the electrospinning method. Methods: The Design-Expert version13 software was used in experimental designing, to ensure an efficient nanofiber preparation process. Several nanofiber formulations were prepared with different concentrations of drug and polymers. In this study, Ketoconazole was selected as the model drug, ketoconazole is widely used as an antifungal drug in the treatment of fungal infections. Eudragit and Polyethylene glycol polymers were used with ketoconazole to formulate electrospun nanofibers. Then Ketoconazole nanofibers were investigated and evaluated chemically and morphologically by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results: Utilizing the electrospinning method, Ketoconazole electrospun nanofiber was successfully fabricated. The producedketoconazole-loaded nanofibers mat was formulated as a dermal patch. The Eudragit and polyethylene glycol polymers revealed goodcharacteristics that led to the production of uniform ketoconazole nanofibers. The prepared patch showed good physical and mechanicalproperties. The SEM results Images for the produced nanofiber mat showed good nanofiber distribution and no beads formation withseveral fiber diameter sizes, while Fourier Transform Infrared Spectroscopy findings revealed the conjugation between polymers andketoconazole pure powder, the major characteristic peaks of ketoconazole appeared in the FTIR spectrum. Formula 7 showed minimumnanofibers diameter with maximum entrapment efficiency. Conclusions: In this study, the use of the electrospinning method completed the formulation of a dermal patch containing antifungalnanofibers successfully. Using design expert software to ensure maximum optimization, two biocompatible polymers were used, Eudragit E100 and PEG 600 to formulate ketoconazole nanofibers. The formulated dermal patch could be promising for pharmaceutical antifungal applications.

Nanocellulose separation from barley straw via ultrasound-assisted choline chloride – Formic acid deep eutectic solvent pretreatment and high-intensity ultrasonication

The present study aims at investigating the application of ultrasound assisted choline chloride (ChCl) – formic acid (FA) deep eutectic solvent (DES) pretreatment of Barley straw. In addition, the efficiency of a wet grinding followed by high intensity ultrasound (HIUS) treatment for production of cellulose nanofibers (CNF) has been evaluated. The DES (using ChCl: FA at 1:9 M ratio) treatment at 45 kHz ultrasound frequency and 3 h of treatment duration resulted in 84.68 ± 1.02 % and 82.96 ± 0.79 % of lignin and hemicellulose solubilisation, respectively. The purification of DES treated solid residue resulted in cellulose with more than 90 % purity. Further, 10 min of wet grinding followed by 40 min of HIUS treatment resulted in more than 80 % nano-fibrillation efficiency. The produced CNF had diameters less than 100 nm in number size distribution and type I cellulose structure. This study confirmed that the developed process offers a sustainable method for producing nanocellulose from agricultural waste.

Urea-lactic acid as efficient lignin solvent and its practical utility in sustainable electrospinning

The development of lignin-based materials presents a promising avenue for advancing green chemistry and mitigating environmental impact. However, the key challenge lies in the processability of lignin, which significantly affects its practical applications. Addressing the issues related to lignin's complex structure, variability, and reactivity is crucial for optimizing its incorporation into high-performance materials. Therefore, in this study we explore the efficacy of a urea-lactic acid-based deep eutectic solvent (ULA) for the dissolution of kraft lignin, aiming to enhance its practical utility in sustainable electrospinning processes, for the first time. Results of elemental analysis, IR and 2D NMR spectroscopy, provide crucial insights into the structural properties of the regenerated material post-DES treatment. The findings confirm a high lignin recovery rate, reaching up to 96.6 % for samples dissolved at 100°C. Additionally, 2D NMR analysis indicates that the process leads to partial esterification of lignin with lactate ions. The ability of the studied DES to effectively solubilize lignin underscores its potential as an efficient lignin solvent and facilitates the fabrication of lignin-based nanofibers via electrospinning. The incorporation of this DES in electrospinning processes promises significant advancements in the development of sustainable, lignin-derived materials and offers a green alternative for production of high-performance nanofibers. Preliminary results of electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements confirm that the EDLC with prepared hydrogel electrolyte demonstrates attractive electrochemical properties (specific capacitance, CSP = 95 F g–1; series resistance RS = 2.2 Ω; charge transfer resistance, RCT = 1.6 Ω), which are comparable with the reference cell based on a commercial glass fibre separator. Hence, the DES-assisted-electrospinned lignin membrane can be viewed as a potential gel electrolyte matrix for practical use in construction of sustainable energy storage devices.

Continuous Nanofiber Bundle Production Using Helical Spinnerets with Different Configurations in Needleless Electrospinning

This study investigates the production of continuous nanofiber bundles using needleless electrospinning with a focus on helical spinneret configurations. It delves into the effects of spinneret diameter, pitch length, and thickness on nanofiber bundle characteristics, employing polyacrylonitrile as the polymer. The research highlights the significant impact of these parameters on the nanofiber morphology, bundle width, productivity, and deposition properties of nanofiber bundles. Scanning electron microscopy imaging, bundle depositions analyses, and electric field modeling with COMSOL Multiphysics are applied for the nanofiber bundles electrospun by helical spinnerets. As the diameter of the spinneret increases, productivity, bundle width, deposition ratio, deposition intensity, and deposition homogeneity are increased significantly. Additionally, an increase in spinneret thickness leads to a decrease in average nanofiber diameter. Specifically, increasing the spinneret diameter from 30 to 50 mm, pitch length from 20 to 40 mm, and reducing thickness from 3 to 1 mm increases productivity by 170%, 72%, and 32%, respectively. As a result of practical and modeling studies on helical spinnerets, the optimized parameters are determined as 1 mm thickness, 40 mm pitch length, and 50 mm diameter.

Fabrication of tetra‐n‐butylammonium hydrogen sulfate‐based poly(lactic acid)‐poly(ethylene glycol) composite electrospun wound dressing

AbstractIn this study, poly(lactic acid)‐poly(ethylene glycol)‐tetra‐n‐butylammonium hydrogen sulfate (PLA‐PEG‐HS) electrospun mats were fabricated by electrospinning as effective wound dressings against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), which are the most prevalent species of gram‐positive and gram‐negative bacteria, respectively. PLA is a polymer with high biocompatibility and biodegradability, but its structure is fragile. Therefore, we aimed to improve its structural properties using PEG as a plasticizer and to provide antibacterial properties with HS salt. The nanofibers characterized using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), and drying time tests. The addition of HS eliminated the beads in the PLA‐PEG nanofiber and improved the homogeneity of the fiber distribution. Concerning this result, when the liquid absorption capacity (LAC) test was evaluated, PLA‐PEG‐HS nanofiber production was achieved with the highest rate of 480.95%. The thermal properties of nanofibers increased with the addition of HS. Cytotoxicity test results of PLA‐PEG‐HS wound dressings showed high cell viability of 129.05% in L292 mouse fibroblast cells at the end of the 24th hour. PLA‐PEG‐HS nanofibers with 99.99% antibacterial activity against tow bacteria. Considering the modern wound dressing requirements, antibacterial wound dressing production has been successfully achieved.