Search Results (4,557)

In the present work, the elastic modulus of several types of polymer nanocomposites has been analyzed with a semiempirical model which takes into consideration agglomerate formation and their impact on the nanocomposites’ mechanical performance. The nanocomposites under investigation were either hybrids with a combination of graphene oxide (GO) with multi-walled carbon nanotubes (MWCNTs) or carbon nanofibers (CNFs) at various loadings, or monofillers with varying nanoparticle sizes, at a constant nanofiller loading. In addition, the effect of the type of polymeric matrix on the same nanofiller combinations has been examined. The basic assumption of two phases, namely a matrix with finely dispersed nanoparticles coexisting with agglomerates, was analyzed. The elastic stiffness of the first phase was calculated by the Mori–Tanaka model, and hereafter a semiempirical model was utilized for the estimation of the agglomerates’ stiffness. Within the context of this model, it was shown that the agglomerates’ volume fraction, combined with the nanoparticles’ density, namely the nanoparticles’ volume fraction in the agglomerates and consequently the inclusions’/agglomerates’ enhanced modulus, may cause a substantial improvement in the Young’s modulus, which cannot be explained by conventional mechanical models. These results apply to both nanocomposite types, hybrids at various nanofiller loadings and monofillers with varying particle sizes. Full article

To address inherent limitations of chitosan-based edible films, including inadequate mechanical strength and poor moisture resistance, cellulose nanofibers (CNF) were employed as a synergistic film-forming component to partially substitute chitosan in the fabrication of ternary composite films (denoted as CSTF-CNFs). This approach was based on a previously developed chitosan matrix modified with tannin-Fe³⁺ nanoparticles (TF). It was hypothesized that CNF could function as a reinforcing scaffold to improve the dispersion of TF within the film matrix and, through hydrogen bonding and physical entanglement, form an interpenetrating fiber network with chitosan, thereby enhancing the structural and barrier properties of the films. The present study systematically evaluated the influence of varying CNF substitution ratios (0–30%) on the physicochemical characteristics of the resulting composite films and their performance in tomato preservation. The results demonstrated that an appropriate CNF incorporation facilitated the formation of a dense, cross-linked network with chitosan and TF via hydrogen bond interactions, significantly improving both mechanical strength and water resistance. Among all formulations, the CSTF-CNF20 film exhibited optimal comprehensive performance, achieving the highest tensile strength of 27.60 MPa. Moreover, its swelling ratio markedly decreased from 675.5% (CSTF-CNF0) to 120.9%, while the water contact angle increased to 113.7°, and the DPPH radical scavenging activity remained above 85%. Tomato preservation assays revealed that, in comparison with the untreated control and polyethylene film-wrapped groups, the application of CSTF-CNF20 coating effectively mitigated the decline in weight loss and firmness, preserved surface color integrity, and resulted in the highest L* value alongside the lowest soluble solids content. These findings suggest that the synergistic integration of CNF with nano-scale metal–phenolic networks offers a viable strategy for developing high-performance chitosan-based edible films. The CSTF-CNF20 composite film holds significant promise for application in the postharvest preservation of fruits and vegetables. Full article

Background: Erectile dysfunction (ED) and premature ejaculation (PE) are prevalent conditions affecting men’s sexual health, for which tadalafil and dapoxetine have shown promise in their treatment, respectively. Conventional oral dosage forms face limitations, including variable absorption and delayed onset of action. In this study, we developed electrospun nanofibers using polyvinylpyrrolidone for buccal drug delivery as an alternative dosage form to oral tablets. This route offers advantages such as easy administration, suitability for those with difficulty swallowing, particularly the elderly, and a rapid onset of action via the blood capillaries, which might improve bioavailability. Methods: PVP nanofibers loaded with tadalafil and dapoxetine were fabricated using a modified electrospinning procedure with the Spraybase system, where an 8% (w/v) PVP ethanol solution containing 1.5% dapoxetine and 0.5% tadalafil was electrospun under controlled conditions (800 µL/h flow rate, 15 cm distance, 0.55 mm needle, and 8–10 kV) to produce uniform fibers. Results: The morphology of the nanofibers was characterized using SEM, revealing smooth, uniform fibers with an average diameter of 218 ± 50 nm for drug-loaded nanofibers. This nanofibrous system also demonstrated ultra-rapid disintegration occurring within 4 ± 1 s and consistent drug loading and encapsulation efficiency for both drugs. The release profile showed a burst drug release after 15 min, which accounted for >45% for tadalafil and >50% for dapoxetine, followed by a sustained increment in the drug release that reached > 60% for tadalafil and >78% for dapoxetine after 30 min until a complete drug release (100%) for both drugs after 180 min. In vitro cytotoxicity studies on human dermal fibroblasts confirmed the safety of both medications, with cell viability exceeding 50%, at concentrations of 1.56 to 25 µg/mL for tadalafil and 4.69 to 9.38 µg/mL for dapoxetine after 24 and 48 h of incubation. Conclusions: These findings highlight the potential of PVP-based nanofibers as a novel buccal delivery system for the combined treatment of ED and PE. Full article

To enhance the mechanical properties and waterproof performance of polymer–cement (JS) waterproof coatings, cellulose nanofibrils (CNFs) were surface-modified using vinyltriethoxysilane (VTES). The modified cellulose nanofibrils (m-CNFs) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) analysis, and energy-dispersive X-ray spectroscopy (EDS). JS waterproof coatings incorporating m-CNFs were subsequently prepared. The performance and mechanism were systematically evaluated using the tensile strength, bonding strength, water absorption, contact angle, permeability test, durability test, scanning electron microscopy, Brunauer–Emmett–Teller (BET) and atomic force microscopy (AFM). The results indicated that the coating exhibited optimal performance when 1 wt% m-CNFs were incorporated. Under this condition, the tensile strength and bonding strength increased by 33.8% and 9.8%, respectively, while the 7-day water absorption decreased by 72.9%. The contact angle reached 97.1°, and the durability of the coating was also improved. Moreover, the amphiphilic nature introduced by silane modification effectively improved the interfacial adhesion between the organic and inorganic phases within the coating. In addition, due to their water absorption capacity, m-CNFs fill the micropores of the coating during the curing process and produce an internal curing effect, thereby reducing the porosity of the material. As a result of these synergistic effects, the mechanical strength and hydrophobicity of the JS waterproof coating are significantly enhanced. This study expands the application of CNFs, a sustainable nanomaterial, in building waterproofing materials. Full article

Chitosan, owing to its abundant amino and hydroxyl functional groups, serves as an effective biosorbent for the removal of toxic metal(loid) ions from water. This review summarizes recent advances in chitosan-based adsorbents specifically for arsenate (As(V)) and copper ions (Cu(II)), with an emphasis on adsorption mechanisms and electrospun nanofiber technologies. A conceptual “charge adaptation–structure synergy” model is proposed to elucidate the distinct adsorption behaviors of chitosan toward anionic and cationic substances: under acidic conditions, As(V) adsorption is dominated by electrostatic attraction to protonated amino groups, whereas at pH values near or above the pKa, Cu(II) removal proceeds via synergistic chelation involving deprotonated amino and hydroxyl groups. Competitive and synergistic interactions in binary systems, particularly between As(V) and coexisting anions such as phosphate, are also discussed. Notably, the kinetic advantages of electrospun chitosan nanofibers are highlighted, with equilibrium times shortened from several hours to approximately 0.5–2.6 h. Key challenges and future research directions are further discussed, including scalable manufacturing and the treatment of complex wastewater matrices. Full article

Effective hemostasis in deep and irregular wounds remains a critical clinical challenge. To address this, we developed a bioresorbable chitosan composite hydrogel reinforced with short eggshell membrane (ESM) nanofibers, which were obtained through cryogenic grinding. The resulting ESM/CCS hydrogel, crosslinked with citric acid, exhibited significantly enhanced properties compared to pure CCS hydrogel, including a 63% increase in mechanical strength, a two-fold improvement in shape memory, a 25.31% reduction in hemolysis, over 2% higher cytocompatibility, and more than 48% greater hemostatic efficiency. Structural characterization confirmed the successful integration of bioactive chitosan with collagen mimetic ESM nanofibers. This biomimetic approach synergistically combines mechanical reinforcement with biological functionality, highlighting its strong potential as an advanced hemostatic dressing for complex wound management. Full article

Electrospinning is a versatile technique for producing polymer nanofibers with high ratios of surface area to volume and tunable porosity. Conventional approach to the optimization of processing parameters such as voltage and flow rate frequently encounters limitations in reproducibility and scalability. This review proposes a comprehensive framework that integrates macromolecular design principles with established electrohydrodynamic theories. We analyze how intrinsic molecular traits, specifically chain entanglement density, molecular weight distribution (MWD), topological architecture, and polymer–solvent thermodynamic interactions, define the boundaries of jet stability and solidification. Key findings highlight that while molecular weight establishes a baseline for spinnability, the MWD dictates the dynamic response under extreme deformation. Notably, high-molecular-weight fractions act as elastic load-bearers that suppress capillary breakup. Furthermore, we discuss here how molecular architecture and solvent-mediated segmental mobility determine whether molecular orientation is kinetically trapped or relaxed during the nanosecond timescales of jet flight. By establishing a hierarchical design logic prioritizing molecular and formulation variables over processing parameters, this framework provides a robust strategy to overcome challenges in scalability and reproducibility, positioning electrospinning as a sensitive probe for macromolecular dynamics under extreme elongation. Full article

Semiconductor miniaturization demands stricter material uniformity. Core-shell nanofibers, promising for semiconductor packaging and flexible circuits, face application limits due to traditional coaxial electrospinning’s electric field instability—causing poor fiber diameter uniformity and challenges with high-viscosity and low-conductivity solutions. To address this, airflow-assisted coaxial electrospinning leveraged airflow-electric field synergy to enhance fiber stretching. COMSOL Multiphysics 6.4 simulated the influence of different inner diameters of the air flow nozzles on the air flow field, while the response surface method optimized parameters. At 10 kPa air pressure, 16.71 kV voltage, and a gas nozzle inner diameter of 3.42 mm, nanofibers showed regular morphology with a diameter coefficient of variation as low as 9.2%. This study enables stable preparation of highly uniform core-shell nanofibers, providing key process support for their large-scale semiconductor application and advancing flexible electronics and photodetection. Full article

Background/Objectives: Fungal keratitis remains a vision-threatening infection, and current amphotericin B (AmphB) eye drops suffer from low corneal residence time, poor aqueous solubility, and the need for frequent dosing. This study develops electrospun nanofiber-based ophthalmic inserts combining polyvinyl alcohol (PVA), gamma-cyclodextrin (γ-CD), and sodium taurocholate (STC) to enhance AmphB solubility and provide a non-invasive, rapidly dissolving ophthalmic dosage form. Methods: γ-CD and STC-enhanced AmphB-loaded PVA nanofiber-based ophthalmic inserts with varying γ-CD and STC concentrations were prepared by electrospinning and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Drug content, in vitro release (Weibull modeling), antifungal activity against Candida albicans, Fusarium solani, and Aspergillus fumigatus, ocular cytocompatibility using the Hen’s Egg Test on Chorioallantoic Membrane (HET-CAM), and accelerated stability (40 ± 2 °C, 75 ± 5% relative humidity, 4 weeks) were evaluated. Results: Bead-free nanofibers with mean diameters between 216 ± 33 nm and 310 ± 35 nm were obtained, and XRD confirmed complete amorphization of AmphB within the PVA nanofiber matrix, forming an amorphous solid dispersion. All formulations showed rapid and nearly complete AmphB release (≈100% within 60 min), with Weibull β values < 0.75, indicating Fickian diffusion-controlled release. AmphB-loaded PVA nanofiber-based ophthalmic inserts produced inhibition zones and broth susceptibility profiles comparable to AmphB in dimethyl sulfoxide (DMSO), demonstrating preserved antifungal activity. HET-CAM scores (0–0.9) classified the inserts as practically non-irritant, and SEM/FTIR after accelerated storage showed no relevant morphological or physicochemical changes. Conclusions: These γ-CD and STC-enhanced AmphB-loaded PVA nanofiber-based ophthalmic inserts provide a non-invasive, rapidly dissolving ophthalmic dosage form that combines amorphous AmphB, immediate drug availability, and good ocular tolerance, supporting their further development as a patient-friendly treatment option for fungal keratitis. Full article

The practical application of inorganic ferroelectric fillers in flexible piezoelectric composites is critically constrained by low polarization efficiency and severe interfacial incompatibility with polymer matrices. Herein, we report a multi-level in situ surface modification strategy that simultaneously addresses both limitations. High-purity one-dimensional tetragonal barium titanate nanofibers (BTO NFs) are first synthesized via sol–gel electrospinning combined with a two-step gradient annealing process, which precisely controls phase evolution and preserves structural continuity. To overcome the detrimental acid-induced degradation of BTO NFs during functionalization, a polydopamine (PDA) buffer layer is first conformally coated, followed by the liquid-phase deposition of a conductive polypyrrole (PPy) shell, forming a robust core–shell PPy@PBT NFs architecture. Incorporating only 4 wt% of these multifunctional fillers into a poly(vinylidene fluoride) (PVDF) matrix yields a dramatic enhancement in electromechanical performance. The resulting flexible piezoelectric energy harvesters achieve a piezoelectric coefficient (d₃₃) of 28.7 pC/N, an output voltage of 13 V, and an output current of 0.7 μA, representing substantial improvements over unmodified filler systems. This synergistic enhancement originates from the PDA-mediated interfacial stress transfer and the PPy-induced Maxwell–Wagner polarization intensification, establishing a robust and generalizable paradigm for high-performance flexible piezoelectric composites in self-powered wearable electronics. Full article

This study investigated mechanical properties of composite materials consisting of an isotactic polypropylene (iPP) matrix reinforced with whisker-like fillers: carbon nanofibers (CBNF) and wollastonite (WN). We strove to develop mechanical models specifically for predicting yield stress and fracture toughness. Experimentally obtained results validated findings obtained using the proposed models. Regarding the elastic modulus, data suggest that conventional rules of mixture, typically used for glass fiber-reinforced polymers, remain applicable, indicating that filler addition enhances stiffness in a predictable manner. However, yield stress and fracture toughness exhibited distinct behaviors. Results revealed that these properties are governed predominantly by shear yielding of the iPP matrix rather than reinforcement effect of the fillers. Despite the presence of whiskers, the overall yield and fracture mechanisms depend heavily on the matrix’s plastic deformation and energy dissipation. The constructed models consistently explain these findings, supporting quantitative evaluation of the matrix’s contribution. These results emphasize that developing high-performance iPP composites requires knowledge of the intrinsic ductile properties of the matrix alongside filler selection and dispersion. Full article

Ocular infections and inflammation represent a clear risk to eye health, but standard eye masks often lack the necessary therapeutic features. Moreover, most existing studies employ a blended electrospinning approach, which leads to an inhomogeneous spatial distribution of the therapeutic agents. However, using the coaxial technique can address these limitations. This study develops a coaxial electrospun nanofibrous eye mask with dual antibacterial and antioxidant functions, aiming to provide an innovative ocular treatment tool for eye care. Generally, a core-shell structured bilayer polycaprolactone-polylysine/polyvinyl alcohol-resveratrol (PCL-PLs/PVA-RSV) membrane is successfully prepared by coaxial electrospinning, where the core is resveratrol-loaded PVA and the shell is PLs-loaded PCL. Results show uniform fiber morphology, favorable hydrophilicity, and potential for sustained release due to core-shell design. The membrane significantly inhibits the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli); at the same time, it exhibits excellent free radical scavenging ability and good component biocompatibility, achieving slow release of the two drugs and long-term antioxidant effect. This multifunctional platform offers a synergistic approach to combating microbial infection and oxidative stress, showing great potential for eye care. Full article

Ocular fungal diseases are associated with severe infection and pain and, in advanced stages, can lead to vision loss. Current treatment options are limited to the topical application of conventional drugs, and the bioavailability of these drugs is quite limited due to ocular barriers. In this study, a dual-drug nanodelivery system was developed to improve intraocular drug delivery by combining antifungal and anti-inflammatory therapies. Posaconazole (PSC), a broad-spectrum triazole antifungal agent, and dexketoprofen trometamol (DKP), a rapidly acting nonsteroidal anti-inflammatory drug, were co-loaded onto polymeric micelles and then incorporated into electrospun poly(vinyl alcohol)/poly(vinylpyrrolidone) (PVA/PVP) nanofiber intraocular implants. DSC, XRD, FTIR, and FESEM analyses showed that both APIs were successfully converted into nanofiber form without disrupting the micelle structure. Comparative studies with DKP solution and PSC commercial oral suspension (Noxafil^® 40 mg/mL) showed that the produced micelle-loaded nanofibers provided sustained release and significantly increased ex vivo ocular permeation and penetration. In vitro antifungal activity tests demonstrated efficacy against Candida albicans, and HET-CAM toxicity tests showed that the micelle-loaded nanofibers were non-irritating and suitable for ocular application. Overall, the micelle-loaded electrospun nanofiber ocular inserts developed in this study represent a promising platform for combined antifungal and anti-inflammatory ocular therapy. Full article

Electrospinning is the most widely used technique for creating nanofibers. However, the low production rate and the usage of a high-voltage setup have become obstacles to its widespread application. One effective method for creating nanofibers from a variety of materials is centrifugal spinning. This review discusses centrifugal spinning (CS) as an effective and scalable nanofiber manufacturing technology, particularly in filtration systems, and presents it as a promising alternative to existing methods, such as electrospinning. The review highlights the advantages of CS, including its high production rate, cost efficiency, and the ability to process various materials to produce nano- and microfibers. Despite its high potential, the issues associated with CS technology include the unpredictability of fiber quality, the inability to control diameters, and the need for more robust mathematical models to predict fiber characteristics. To eliminate these shortcomings and further enhance the industrial utility of centrifugally spun nanofibers in filtration, future studies should focus on improving process control, exploring a broader range of polymers, optimizing melt electrospinning, and designing more advanced nozzle profiles. Full article

The production and use of plastics have direct consequences on the environment, such as the greenhouse gas emissions (GHGs) they cause. Therefore, it is necessary to develop materials from renewable sources with a lower environmental impact to replace plastic. In this work, films with bioactive properties have been developed from cellulose nanofibers (CNFs) and natural phenolic compounds for food packaging applications. First, the optimization of the incorporation of three different natural phenolic compounds (tannic acid, p-coumaric acid, and acetosyringone) into nanocellulose was studied using a Box–Behnken design, with the phenols adsorbed by the nanocellulose as the output variable. Once the incorporation was optimized, films containing nanocellulose and phenolic compounds were produced and characterized. Tannic acid showed the best results with regard to the optical properties of the resulting films and achieved a complete blocking of UV-B radiation, as well as adding to nanocellulose antioxidant (4.32 mM TE/g film) and antibacterial capacity (log R of 6.6 ± 0.2 and 3.8 ± 0.1 for Staphylococcus aureus and Escherichia coli, respectively), making these films a promising material for use in contact with food as a packaging material, although more in-depth studies and measures are needed to make these films viable for use in food packaging. Full article