Nanofiber Mats Research Articles

Formulation, Characterization and Evaluation of Minocycline Hydrochloride Loaded Polyurethane/Collagen Nanofibers via Electrospinning as Wound Dressings

Objective It was aimed to formulate minocyline.HCI loaded electrospun polyurethane/collagen (PU/Col) and polyurethane/collagen/polycaprolactone (PU/Col/PCL) nanofibers are intended for use as a wound dressing. Methods:The effect of polymer ratio and addition of PCL on the morphology, diameter, drug delivery, encapsulation efficiency, mechanical properties, antibacterial activity against Escherichia coli and Staphylococcus aureus, cytotoxicity, cell adhesion and proliferation were investigated. 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to test the cytotoxicity of the nanofibers on the human dermal fibroblast (HDF) cell line. Cell proliferation/adhesion was also determined by imaging HDF cells seeded on mats with scanning electron microscopy/fluorescence microscopy. Results:All nanofibers were bead-free and smooth in the diameter range of 866.7-882.4 nm. They had favorable encapsulation efficiency (≥79.3%), controlled drug release up to 24 hours and did not have cytotoxic effects. Although collagen was preferred for cell adhesion and proliferation, its spinnability and mechanical properties were poor. While PU improved the spinnability of collagen, its mechanical properties also enhanced with the addition of PCL. Nevertheles, all mats led to favorable cell adhesion and proliferation. All the nanofibers had antimicrobial activity against Escherichia coli and Staphylococcus aureus. Conclusion:In conclusion, PU/Col and PU/Col/PCL nanofiber mats, which had favorable encapsulation efficiency, controlled drug release and antibacterial activity at least 24 hours, cell viability, proliferation, adhesion, mechanical properties to be used as wound dressing, were successfully prepared.

Electrospun Multiscale Structured Nanofibers for Lithium‐Based Batteries

Abstract Electrospun is a unique technique for the fabrication of multiscale structured nanofibers (MSNFs), which can be used as functional units for improving the performance of lithium‐based batteries. This review systematically examines how MSNFs, including core–shell, hollow porous, multichannel, wire‐in‐tube, tube‐in‐tube, and hierarchical nanofibers, effectively improve battery performance as components in lithium‐based batteries. The application of aforementioned MSNFs and their chemical modification contributes to the development of lithium‐based batteries with high energy density and enhanced safety when used as electrodes, separators, and electrolytes. Specifically, MSNFs are used to derive electrodes and electrolytes that improve electron/ion transfer rates, increase the utilization ratio of active materials, suppress dendrite growth, and mitigate volume expansion, enabling fast and stable electrochemical reactions at the electrodes. Additionally, MSNFs‐derived separators, which feature more ion transport channels, exceptional mechanical properties, and the capability to inhibit thermal runaway, are also discussed. Finally, the challenges and prospective pathways for electrospun technology in the application of lithium‐based batteries are reviewed.

Correction: El-Hefnawy et al. Fabrication of Nanofibers Based on Hydroxypropyl Starch/Polyurethane Loaded with the Biosynthesized Silver Nanoparticles for the Treatment of Pathogenic Microbes in Wounds. Polymers 2022, 14, 318

There was an error in the original publication [...]

Shore hardness of bulk polyurethane affects the properties of nanofibrous materials differently

The present study shows the effect of the hardness of bulk polyurethane on the properties of nanofibrous materials produced in the solution blow spinning process. This study focuses on nanofibrous materials made from medical-grade polyurethanes with different hardness values on the Shore scale, from 75A to 75D. We aimed to determine the effect of the intrinsic properties of polyurethane used to produce nanofibers on the tensile properties of the resulting nanofibrous materials and in vitro platelet adhesiveness. This study used a solution blow spinning process to produce nanofibrous materials from polyurethane solutions. It evaluates their properties using scanning electron microscopy, followed by porosity determination, tensile testing, and platelet adhesion assays. Generally, the bulk polymer's Shore hardness affects nanofibrous products' porosity and tensile properties. In the tested Shore hardness range, the most visible differences in material properties were observed for the fibers produced from the hardest (75D) and softest (75A) polyurethanes. The nanofibrous material produced using 75D polyurethane exhibited the highest porosity, up to approximately 0.87, owing to the low packing density of the stiff nanofibers. It also remained the stiffest, with the highest Young’s modulus. On the other hand, the softest 75A polyurethane produced a less porous nanofibrous mat with the highest tensile strength among the tested polyurethanes. All tested nanofibrous materials retained their platelet adhesion resistance upon processing into nanofibers, with a mean platelet coverage below 1 % of the nanofibrous mat surface. The study results provide insights into the relationship between the hardness of bulk polyurethane and the properties of nanofibrous materials, which can be useful in various biomedical applications, particularly in producing tissue-engineered vascular grafts.

Development and characterization of antibacterial marine extract-infused cellulose acetate nanofibers as wound dressings for combatting multidrug-resistant wound infections

Wound infections caused by multidrug-resistant bacteria pose a significant challenge globally in healthcare. Traditional wound dressings often lack efficacy against these resilient pathogens, necessitating the exploration of innovative approaches to combat infections and promote wound healing. This study was designed to investigate a novel wound dressing marine extract-infused electrospun cellulose acetate nanofibers (CANF) with particular emphasis on combating multidrug-resistant bacteria. Cellulose acetate solutions were combined with marine extract (Heteroxenia Fuscescens soft coral, H. Fu) before the creation of electrospun nanofibers. The antibacterial activities of H. Fu extract and the prepared nanofiber mats were explored against Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, and Staphylococcus epidermidis. Furthermore, the antibacterial properties of the crude H. Fu extract were directly assessed, showing potent activity against several pathogens. Results displayed that H. Fu extract has a robust antibacterial action against tested bacteria. Different concentrations of H. Fu (0.05 g, 0.1 g, 0.2 g, and 0.3 g) were added to CA solution, and named as H. Fu-1@CANF, H. Fu-2@CANF, H. Fu-3@CANF and H. Fu-4@CANF, respectively. The obtained results from SEM analysis demonstrated the smooth and uniform fibers. As observed, the addition of H. Fu with specific concentrations (0.05 g, 0.1 g, 0.2 g) has no significant impact on the smooth properties of the formed nanofibers. Increasing the concentration of H. Fu (0.3 g) leads to the formation of nanofibers coated with huge beads. FTIR affirmed the existence of H. Fu that blended with CANF. The hydrophilicity of the formed CANF was significantly enhanced thanks to the presence of H. Fu extract. The contact angle values of CANF, H. Fu-1@CANF, H. Fu-2@CANF, and H. Fu-3@CANF were 33.3°, 57.1°, 60.8° and 62.9°, respectively. The mechanical properties in terms of ultimate force (kg) recoded values were 0.89, 0.95, 1.2, 1.3 for CANF, H. Fu-1@CANF, H. Fu-2@CANF and H. Fu-3@CANF, respectively, those of CNF were markedly enhanced when loaded with H. Fu. This study evaluates the antibacterial efficacy of nanofiber mats loaded with H. Fu extract against common cutaneous bacterial pathogens. Four nanofiber samples were tested for their inhibitory impact on bacterial survival counts using the disc diffusion method. Important results from the study include the observation that H. Fu-3@CANF exhibited the largest zones of inhibition (ZOI) with diameters of 35 ± 0.25 mm for P. aeruginosa, 32 ± 0.65 mm for A. baumannii, 28 ± 0.14 mm for S. aureus, and 27.6 ± 0.48 mm for S. epidermidis. Additionally, the H. Fu-2@CANF sample demonstrated strong antibacterial activity, with ZOI diameters of 32 ± 0.56 mm, 29 ± 0.81 mm, 26 ± 0.27 mm, and 25.4 ± 0.28 mm for the respective bacteria. The Microtox® assay further evaluated the toxicity levels of the nanofiber mats, revealing that while all samples exhibited some toxicity, the H. Fu-3@CANF sample had the lowest toxicity profile. These findings highlight the potential of H. Fu-loaded nanofibers, particularly H. Fu-3@CANF, for broad-spectrum antibacterial applications. The study underscores the importance of incorporating bioactive compounds into nanofiber mats to enhance their antimicrobial properties, making them suitable candidates for medical and environmental applications requiring effective bacterial eradication.

Cellulose Acetate-Based Wound Dressings Loaded with Bioactive Agents: Potential Scaffolds for Wound Dressing and Skin Regeneration.

Wound healing and skin regeneration are major challenges in chronic wounds. Among the types of wound dressing products currently available in the market, each wound dressing material is designed for a specific wound type. Some of these products suffer from various shortcomings, such as poor antibacterial efficacy and mechanical performance, inability to provide a moist environment, poor permeability to oxygen and capability to induce cell migration and proliferation during the wound healing process. Hydrogels and nanofibers are widely reported wound dressings that have demonstrated promising capability to overcome these shortcomings. Cellulose acetate is a semisynthetic polymer that has attracted great attention in the fabrication of hydrogels and nanofibers. Loading bioactive agents such as antibiotics, essential oils, metallic nanoparticles, plant extracts, and honey into cellulose acetate-based nanofibers and hydrogels enhanced their biological effects, including antibacterial, antioxidant, and wound healing. This review reports cellulose acetate-based hydrogels and nanofibers loaded with bioactive agents for wound dressing and skin regeneration.

A closed-loop sustainable method for the fabrication of electrospun nanofiber using food waste for filtration of particulate matters (PMs) and volatile organic matter (VOCs) from air

A closed-loop sustainable method for the fabrication of electrospun nanofiber using food waste for filtration of particulate matters (PMs) and volatile organic matter (VOCs) from air

Enhancement of 5-Fluorouracil Drug Delivery in a Graphene Oxide Containing Electrospun Chitosan/Polyvinylpyrrolidone Construct

Electrospun nanofibrous mats, consisting of chitosan (CS) and polyvinylpyrrolidone (PVP), were constructed with the addition of graphene oxide (GO) for enhancement of delivery of the 5-Fluorouracil (5-Fu) chemotherapy drug. Upon studying the range of GO concentrations in CS/PVP, the concentration of 0.2% w/v GO was chosen for inclusion in the drug delivery model. SEM showed bead-free, homogenous fibres within this construct. This construct also proved to be non-toxic to CaCo-2 cells over 24 and 48 h exposure. The construction of a drug delivery vehicle whereby 5-Fu was loaded with and without GO in various concentrations showed several interesting findings. The presence of CS/PVP was revealed through XPS, FTIR and Raman spectroscopies. FTIR was also imperative for the analysis of 5-Fu while Raman exclusively highlighted the presence of GO in the samples. In particular, a detailed analysis of the IR spectra recorded using two FTIR spectrometers, several options for determining the concentration of 5-Fu in composite fibre systems CS/PVP/5-Fu and GO/CS/PVP/5-Fu were demonstrated. By analysis of Raman spectra in the region of D and G bands, a linear dependence of ratios of integrated intensities of AD and AG on the intensity of host polymer band at 1425 cm−1 vs. GO content was found. Both methods, therefore, can be used for monitoring of GO content and 5-Fu release in studied complex systems. After incorporating the chemotherapy drug 5-Fu into the constructs, cell viability studies were also performed. This study demonstrated that GO/CS/PVP/5-Fu constructs have potential in chemotherapy drug delivery systems.

Using Polycaprolactone Nanofibers for the Proof-of-Concept Construction of the Alveolar-Capillary Interface.

The alveolar-capillary interface is the key functional element of gas exchange in the human lung, and disruptions to this interface can lead to significant medical complications. However, it is currently challenging to adequately model this interface invitro, as it requires not only the co-culture of human alveolar epithelial and endothelial cells but mainly the preparation of a biocompatible scaffold that mimics the basement membrane. This scaffold should support cell seeding from both sides, and maintain optimal cell adhesion, growth, and differentiation conditions. Our study investigates the use of polycaprolactone (PCL) nanofibers as a versatile substrate for such cell cultures, aiming to model the alveolar-capillary interface more accurately. We optimized nanofiber production parameters, utilized polyamide mesh UHELON as a mechanical support for scaffold handling, and created 3D-printed inserts for specialized co-cultures. Our findings confirm that PCL nanofibrous scaffolds are manageable and support the co-culture of diverse cell types, effectively enabling cell attachment, proliferation, and differentiation. Our research establishes a proof-of-concept model for the alveolar-capillary interface, offering significant potential for enhancing cell-based testing and advancing tissue-engineering applications that require specific nanofibrous matrices.

Key Advances in Solution Blow Spinning of Polylactic-Acid-Based Materials: A Prospective Study on Uses and Future Applications

Solution blow spinning (SBS) is a versatile and cost-effective technique for producing nanofibrous materials. It is based on the principles of other spinning methods as electrospinning (ES), which creates very thin and fine fibers with controlled morphologies. Polylactic acid (PLA), a biodegradable and biocompatible polymer derived from renewable resources, is widely used in biomedical fields, environmental protection, and packaging. This review provides a theoretical background for PLA, focusing on its properties that are associated with structural characteristics, such as crystallinity and thermal behavior. It also discusses various methods for producing fibrous materials, with particular emphasis on ES and SBS and on describing in more detail the main properties of the SBS method, along with its processing conditions and potential applications. Additionally, this review examines the properties of nanofibrous materials, particularly PLA-based nanofibers, and the new applications for which it is thought that they may be more useful, such as drug delivery systems, wound healing, tissue engineering, and food packaging. Ultimately, this review highlights the potential of the SBS method and PLA-based nanofibers in various new applications and suggests future research directions to address existing challenges and further enhance the SBS method and the quality of fibrous materials.

Synthesis and characterization of novel electrospun nanofibers based on taro starch: influence of solvent and isolation agent on morphology and diameter

AbstractThe utilization of natural polymers in producing electrospun nanofibers has received significant attention due to their biocompatibility, sustainability and diverse range of applications. This research focuses on synthesizing electrospun nanofibers derived from taro starch isolated from tubers. The investigation utilized SEM to examine the structure and size of the electrospun nanofibers. Formic acid and dimethyl sulfoxide solvents were tested to determine the most efficient solvent system for synthesizing taro starch nanofibers. The results demonstrated that the taro starch nanofibers can be effectively synthesized when using formic acid as the primary solvent. The study also investigated the impact of altering the volumetric ratio of formic acid to water on nanofiber morphology and size, finding that a lower formic acid fraction produced smooth fibers while a higher fraction resulted in fused fibers. The electrospinnability was further evaluated by comparing the effects of different isolation agents—distilled water and sodium metabisulfite—during the isolation process. The isolation agent significantly affected the fiber diameter, with notable differences observed in the smoothness of taro starch nanofibers at starch solution concentrations of 13, 15 and 17 wt%. Overall, the results of the study showed that the formation of taro starch fibers was influenced by the type of solvent, the volume fraction of the solvent to water, and the starch isolation agent. Successful fabrication of nanofibers from taro starch and its optimization parameters can contribute to the development of environmentally friendly nanofiber materials and offer a variety of applications in biomedicine, food and environmental engineering, such as tissue engineering, wound dressing, drug delivery, functional food delivery and food packaging. © 2024 Society of Chemical Industry.

Gallic acid functionalized silk fibroin/gelatin composite wound dressing for enhanced wound healing.

ABSTRACT
As the incidence of chronic wounds increases, the requirements for wound dressings are rising. The specific aim of this study is to propose a novel gallic acid (GA) functionalized silk fibroin (SF) and gelatin (Gel) composite wound dressing in which GA is used as an antibacterial and wound healing substance. Via electrospinning, SF, Gel, and GA mixed solutions could be conveniently fabricated into a composite nanofiber mat (SF-Gel-GA), consisting of uniform fibers with an average diameter around 134.57 ± 84 nm. The internal mesh structure of SF-Gel-GA provides sufficient drug loading capacity, proper moisture permeability, and proper degradation rate. SF-Gel-GA presents excellent biocompatibility. NIH-3T3 fibroblast cells could adhere and spread stably on the SF-Gel-GA surface with slightly promoted proliferation. In the presence of SF-Gel-GA, the growth of both Gram-positive and Gram-negative bacteria, including Staphylococcus aureusand Pseudomonas aeruginosa, is significantly inhibited in both plate and suspension cultures. A cutaneous excisional mouse wound model proves the efficient ability of SF-Gel-GA to promote wound healing. Compared with pure SF dressing and commercial Tegaderm Hydrocolloid3M dressing, the wound closure rate with SF-Gel-GA treatment is significantly improved. The histological assessments further demonstrate SF-Gel-GA could facilitate collagen deposition, neovascularization, and epithelialization at wound sites to promote wound healing. In conclusion, a novel SF-Gel-GA composite wound dressing with efficient wound healing activities have been developed for chronic wound treatment with broad healing potential.

Sublingual β-Glucan/Vitamin C-loaded nanoparticle-embedded polyethylene oxide nanofibrous mats

Nutritional supplements available in various forms provide the consumer with essential molecules demanded for well-being retention. Despite the conveniences provided by oral administration, significant disadvantages such as hepatic first-pass effect, limited absorption, and age-related swallowing problems have been recognized which should be addressed appropriately. Nano-sized biomaterials, which have recently gained popularity in numerous medical fields, have the potential to resolve these problems. In this study, a drug delivery system was designed for sublingual administration and fabricated as β-glucan/vitamin C-loaded chitosan/tripolyphosphate/polyvinylpyrrolidone (CS/TPP/PVP) nanoparticles (DNPs) embedded in polyethylene oxide (PEO) nanofibrous mats (DNFs). The optimum PNP size and DNP size for sublingual administration were obtained as 236 ± 1 nm and 257 ± 1 nm, respectively. The homogenous appearance of DNFs was demonstrated and measured as 783 ± 290 nm using scanning electron microscopy. The synthesized biomaterials were analyzed chemically, 3D-wisely, and thermally. The in vitro drug release kinetics investigation concluded that the sustained drug release of DNP over 15 days proceeded based on the first-order model, and 99.30 % of vitamin C and 99.70 % of β-glucan were released. Neither pure nor drug-loaded samples showed notable cytotoxicity in the 24-h 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay in the L929 cell line. Herein, it has been comprehended that DNF nutritional supplement can be a promising novel supplement dosage form with ease of use, high efficiency, and bioavailability than the conventional methods.

Bacterial cellulose-graphene oxide composite membranes with enhanced fouling resistance for bio-effluents management

Bacterial cellulose composites hold promise as renewable bioinspired materials for industrial and environmental applications. However, their use as free-standing water filtration membranes is hindered by low compressive strength, fouling, and poor contaminant selectivity. This study investigates the potential of bacterial cellulose-graphene oxide composites membranes for fouling resistance in pressure-driven filtration. Graphene oxide dispersed in poly(ethylene glycol) (PEG-400) is incorporated as a reinforcing filler into 3D network of bacterial cellulose using an in-situ synthesis method. The effect of graphene oxide on in situ fermentation yield and the formation of percolated-network in the composites shows that the optimal membrane properties are reached at a graphene oxide loading of 2 mg/mL. The two-dimensional graphene oxide nanosheets uniformly dispersed into the matrix of bacterial cellulose nanofibers via hydrogen-bonded interactions demonstrated nearly twofold higher water flux (380 L m−2 h−1) with a molecular weight cut-off ranging between 100–200 KDa and a sixfold increase in wet compression strength than pristine BC. When exposed to synthetic organic foulants and bacterial rich feed solutions, the composite membranes showed more than 95% flux recovery. Additionally, the membranes achieved over 95% rejection of synthetic natural organic matter and bacterial rich solutions, showcasing their enhanced fouling resistance and selectivity.

Application of electrospinning and 3D-printing based bilayer composite scaffold in the skull base reconstruction during transnasal surgery

Skull base defects are a common complication after transsphenoidal endoscopic surgery, and their commonly used autologous tissue repair has limited clinical outcomes. Tissue-engineered scaffolds prepared by advanced techniques of electrostatic spinning and three-dimensional (3D) printing was an effective way to solve this problem. In this study, soft tissue scaffolds consisting of centripetal nanofiber mats and 3D-printed hard tissue scaffolds consisting of porous structures were prepared, respectively. And the two layers were combined to obtain bilayer composite scaffolds. The physicochemical characterization proved that the nanofiber mat prepared by polylactide-polycaprolactone (PLCL) electrospinning had a uniform centripetal nanofiber structure, and the loaded bFGF growth factor could achieve a slow release for 14 days and exert its bioactivity to promote the proliferation of fibroblasts. The porous scaffolds prepared with polycaprolactone (PCL), and hydroxyapatite (HA) 3D printing have a 300 μm macroporous structure with good biocompatibility. In vivo experiments results demonstrated that the bilayer composite scaffold could promote soft tissue repair of the skull base membrane through the centripetal nanofiber structure and slow-release of bFGF factor. It also played the role of promoting the regeneration of the skull base bone tissue. In addition, the centripetal nanofiber structure also had a promotional effect on the regeneration of skull base bone tissue.

Electrospun Cellulose Acetate/Poly(Vinyl Alcohol) Nanofibers Loaded with Methyl Gallate and Gallic Acid for Anti-Staphylococcus aureus Applications

Methyl gallate (MG) and gallic acid (GA) are natural compounds with potent activity against methicillin-resistant Staphylococcus aureus (MRSA), a significant global health concern. In this study, MG and GA were incorporated into cellulose acetate (CA) blended with poly(vinyl alcohol) (PVA) to create electrospun nanofibers aimed at combating both methicillin-susceptible S. aureus (MSSA) and MRSA. Key electrospinning parameters—DC voltage, injection flow rate, and syringe tip–collector distance—were optimized, with the best conditions being a 1.5 mL/h flow rate, 30 cm distance, and 20 kV voltage. The resulting nanofiber mats were characterized by SEM, FTIR, DSC, tensile strength testing, contact angle measurement, swelling behavior, and release profiling. Antibacterial properties were assessed using the agar diffusion test. The obtained nanofibers had diameters ranging from 879.33 to 906.13 nm. Among the samples, MG-GA-CA/PVA exhibited the highest tensile strength, good flexibility, and improved stiffness, which was related to enhanced thermal stability and chemical interactions as shown by DSC and FTIR analyses. This formulation also displayed excellent hydrophilicity, swelling properties, and a consistent release profile over 8 to 24 h. Furthermore, MG-GA-CA/PVA showed superior antibacterial activity against both MSSA and MRSA, suggesting its potential as a strong, flexible, and effective anti-S. aureus material.

Natural polymeric biomaterials for managing peripheral nerve injuries : a novel approach for tissue repair and reconstruction.

Peripheral nerve injury serves as a major challenge to clinicians and researchers due to the complexity and functions of peripheral nerves that play the crucial role of transmitting signals between spinal cord and other human body tissues. Biomaterials offer promising solutions for regeneration of nerve tissues owing to their biodegradability, and biocompatibility. They can be fabricated as hydrogels, scaffolds, nanofibrous matrices, and nanoparticles that can facilitate the release of therapeutic molecules to reduce inflammation and promote neuronal growth. Managing peripheral nerve injuries through natural polymeric based biomaterials represents as a novel approach for tissue repair and reconstruction in the field of regenerative medicine. This correspondence will give an insight into the different types of natural polymeric biomaterials that can be efficiently used in managing peripheral nerve injuries.

Sweat Pore-Inspired Functional Nanofiber Fabrics for Sweat Management and Simultaneous Detection.

Functional fabric with directional sweat transport and simultaneous sweat detection is highly desirable in daily life due to its crucial role in ensuring exercise comfort and promoting health. Herein, the inspiration is drawn from both the perspiration function of sweat pores and the backflow prevention feature of the surrounding solid skin to develop bioinspired hydrophobic nanofiber fabric. When combined with commercial cotton, this fabric enables rapid discharge of sweat through the sweat pore-like channels at an ultrafast speed of 240 g s-1 m-2, while effectively preventing backflow around these channels to ensure highly efficient personal drying. The performance of the bioinspired nanofiber fabric surpasses that of five commercially available moisture-wicking fabrics by effectively guiding liquid transport while minimizing residual moisture accumulation on the inner side. Furthermore, a colorimetric analysis system is integrated into the bioinspired nanofiber fabric, which facilitates convenient sampling of sweat samples and detection of biomarkers in sweat such as chloride ion, calcium ion, and pH level. This innovative design based on the concept of sweat pores opens up new possibilities for developing intelligent fabrics, electronic skins, and point-of-care devices.

Electrospun fine-diameter polyimide nanofiber membranes via metal wire-based needle-free technique for high-efficiency PM0.3 filtration at high-temperature

Polyimide (PI) nanofiber materials have garnered attention in the field of high-temperature filtration due to their exceptional thermal stability. Enhancing their filtration efficiency for fine particulate matter (PM2.5–0.3) and exploring their performance limits under high-temperature conditions are crucial for high-temperature filtration applications. In this study, a metal wire-based needle-free electrospinning technique was employed to electrospin polyimide (PI) material, successfully fabricating nanofiber membranes with an average fiber diameter of 122 nm within just 10 min at an elevated electrospinning voltage of 80 kV (electric field:333.33 kV/m). The Fine-diameter PI nanofiber membrane achieved a filtration efficiency of 99.99 % for PM0.3 and operated at a low resistance of 189.18 Pa. After continuous treatment at a high temperature of 390 °C for one hour, the Fine-diameter PI nanofiber membrane still maintained a filtration efficiency of 99.96 % for PM0.3 and was capable of completely filtering PM2.5. This demonstrates the excellent stability and reliability of the Fine-diameter PI nanofiber membrane under extreme temperature conditions. Additionally, the membrane exhibited outstanding hydrophobic properties, with a static contact angle of 130 ± 3°, aiding in maintaining its filtration performance in humid environments. The Fine-diameter PI nanofiber membrane developed in this study offers a novel fabrication strategy for PM filtration in high-temperature environments and provides new insights into its limit performance.

Progress on the Sound Absorption of Viscoelastic Damping Porous Polymer Composites.

Porous polymer composites (PPC) have developed rapidly recently, which are widely used in various industrial fields. Viscoelastic damping is an important behavior of porous polymer composites, and it can determine the sound absorption for noise reduction applications. This review has mainly covered the viscoelastic damping and sound absorption of porous polymer composites. Different fabrication approaches of porous polymer composites are gathered. The mechanism of viscoelastic damping behavior is described, and also the sound absorption properties. Followed by the introduction of enhanced sound absorption of viscoelastic damping porous polymer composites, including the incorporation of fillers, microstructures modification, combination with nanofibrous materials, and multilayer configuration, etc. The incorporated fillers can effectively adjust the interfacial area in composites, and obtain desired bonding conditions. Microstructures modification is an effective tool to improve the morphologies of both polymer matrix and fillers, which can be achieved by chemical treatment and surface coating. The combination with lightweight nanofibrous layer can increase the low frequency absorption. The configuration of multilayer composites can improve both acoustical and mechanical properties for engineering applications. It is hoped that this comprehensive review is benefit for the promising development of porous polymer composites in related fields.