The flame retardancy of thermoplastics used in the automotive sector has been a topical challenge for a long time. Halogenated flame-retarded systems have been the additive of choice for several decades. The main issues include the recycling of polymers containing such halogens and the burning of such plastics releasing toxic fumes. Due to recent regulations, their use is now prohibited and halogen-free solutions are well researched. This study aims to investigate the influence of the combination of phosphonium-based ionic liquid (IL-P) and phosphine oxide (PO) as non-halogenated flame retardants on the mechanical and flame retardancy properties of polyamide 6. Different compounds were prepared in the melt state to ensure a good homogeneity between different constituents. The pelletized strands were transformed into sheets using a cast extrusion film line. To compensate the loss of stiffness caused by the plasticizing effect of flame retardants, 20wt% of unmodified sodium montmorillonite (Na+MMT) was added as a reinforcing filler. Flammability tests were conducted on humid and dry conditioned samples according to UL-94 and FMVSS 302 standards. It was found that PA6/PO compounds only achieved a V-2 classification, whereas the incorporation of IL-P made PA6/PO films attain a UL-94 V-0 ranking. Moreover, the two compositions pass the FMVSS 302 burning rate test. Although the addition of nanoclay made it possible to recover the initial mechanical performances, its inflammability rating deteriorated in UL-94 burning tests. In fact, the presence of clay platelets promoted the combustion of PA6/Na+MMT composites due to the hydrolysis effect initiated by the presence of hydroxyl groups on the surface of the clay lamellae. Nevertheless, the obtained data highlighted that the phosphine oxide combination with a phosphonium ionic liquid was very efficient in improving the flame resistance performance of polyamide 6 and could be transposed to design new halogen-free flame-resistant engineering plastics.

The development of polymer nanocomposites with enhanced electrical conductivity is of considerable interest for advanced technological applications such as sensing, electromagnetic shielding, and printed electronics. In this context, the formation of electrically conductive networks is critical to the functional performance of these materials. Incorporation of multilayer graphene sheets (MLGs) into polymeric matrices enables the formation of three-dimensional conductive networks, characterized by significant increases in electrical conductivity and associated with percolation phenomena. However, a detailed understanding of the factors governing the morphology and connectivity of these networks is still incipient. Previous studies have suggested that mesoscale network connectivity is one of the key factors influencing the conductivity of composite material. This work investigates the formation of electrical percolation networks in MLG/epoxy nanocomposites through an experimental study of the electric domains based on the analysis of images acquired via optical microscopy and electrostatic force microscopy (EFM). Specimens with several MLG concentrations were prepared using a three-roll mill calender. Electrical characterization was performed through direct current conductivity measurements. The electrical domains were evaluated at the microscale (optical) and nanoscale (EFM), providing insights into the local conductive behavior and network formation. The analysis of network connectivity was evaluated using a custom-developed software tool for image processing and quantification of structural network metrics. The results indicate that network conductivity and electrical conductivity are strongly influenced by the density of agglomerates and their degree of interconnection. Topological parameters used to characterize the networks were found to correlate directly with the electrical conductivity of the nanocomposites. Such a correlation highlights the potential of quantitative multiscale analyses to characterize and predict the behavior of electrically conductive networks in graphene-based composites.

Demand for sustainable packaging in the global market has led to the development of environmentally friendly alternatives to conventional plastic materials. This study investigates the synthesis and characterization of Bi₂O₃-loaded chitosan nanocomposite films as advanced eco-friendly packaging materials with enhanced antimicrobial and barrier properties.

Bi₂O₃ nanoparticles (20-50 nm) were produced using controlled precipitation and then embedded in high molecular weight chitosan matrix at 1, 3, 5, and 7 wt% using solution casting coupled with probe sonication. Plasticization of films was achieved using glycerol (30% w/w).

Detailed characterization confirmed α-Biâ‚‚O₃ crystalline phase with homogeneous nanoparticle dispersion throughout the chitosan matrix. The nanocomposite films demonstrated excellent broad-spectrum antimicrobial activity, achieving 99.9% elimination of E. coli and S. aureus within 4 h and complete elimination within 8 h. Growth of A. niger was completely inhibited after 7 days, with reasonable antibacterial activity retained after 30 days under ambient conditions.

Practical food preservation trials using fresh strawberries showed superior performance compared to conventional polyethylene packaging, with 60% less weight loss (8.2% vs. 20.5%), reduced firmness loss (15% vs. 45%), and extended shelf life by 8 days. Microbial counts were significantly reduced, and nutritional quality was better preserved with 23% higher ascorbic acid retention.

Biodegradation studies demonstrated complete degradation within 45 days under composting conditions, with life cycle assessment indicating 65% lower carbon footprint than conventional plastic packaging. The synergistic action of Bi₂O₃ nanoparticles and chitosan matrix exhibits improved mechanical strength, enhanced barrier properties, and sustained antimicrobial activities, demonstrating excellent potential for food packaging applications.

Glioblastoma multiforme (GBM) is one of the most aggressive brain malignancies, with treatment failure often resulting from the restrictive blood–brain barrier (BBB) and the poor solubility of therapeutic agents. Apocynin, a NADPH oxidase inhibitor with anticancer and neuroprotective potential, suffers from low aqueous solubility, limited permeability, and poor bioavailability. To address these challenges, mucoadhesive chitosan-coated self-nanoemulsifying drug delivery systems (SNEDDS) of apocynin were developed and optimized for intranasal delivery. SNEDDS were prepared using Capryol 90 (oil), Tween 20 (surfactant), and Transcutol HP (co-surfactant) and optimized via a Box–Behnken design. The optimized formulation exhibited a mean droplet size of 112.4 ± 3.2 nm, a polydispersity index of 0.21 ± 0.04, and a zeta potential of –18.7 ± 2.1 mV, confirming nanoscale uniformity and stability. After chitosan coating, the zeta potential shifted to +24.6 ± 1.9 mV, indicating successful surface modification and improved mucoadhesive properties. Both uncoated and chitosan-coated SNEDDS demonstrated more than 90% drug release; however, the chitosan-coated system reduced burst release, providing controlled release and minimizing dose dumping. Dissolution studies showed an approximately 4.5-fold enhancement in release compared with pure apocynin. Stability evaluation under temperature variation and freeze–thaw cycles confirmed formulation robustness. SEM, DSC, and PXRD analyses revealed conversion of apocynin from crystalline to amorphous form, correlating with enhanced solubility and dissolution. Collectively, chitosan-coated SNEDDS present a promising mucoadhesive and controlled intranasal delivery platform for apocynin in glioblastoma therapy.

The growing demand for sustainable power in wearable electronics, mobile devices, and self-powered sensors has encouraged research into efficient energy harvesting technologies. Mechanical energy generated from human motion and the surrounding environment represents a promising energy source. Triboelectric nanogenerators (TENGs) have attracted considerable attention due to their high efficiency, scalability, and low cost [1–3]. However, improving material properties to enhance output performance and long-term stability remains a challenge.

In this study, a multilayer TENG was fabricated by sequentially depositing RF-sputtered aluminum-doped zinc oxide (AZO), layered double hydroxide (LDH), and spin-coated poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE). LDH layers were grown via an optimized immersion method to ensure uniform coverage, and PVDF-TrFE solutions with varying concentrations were applied to investigate polymer loading effects.

The AZO/LDH TENG exhibited an output voltage of 164.25 V and a current density of 2.9 µA/cm². The composite layer with the optimal PVDF-TrFE concentration significantly enhanced the output, achieving an output voltage of 641.625 V and a current density of 16.530 µA/cm². This improvement is attributed to increased surface charge density and enhanced dielectric properties of the ferroelectric polymer. Long-term stability tests further confirmed the enhanced performance of PVDF-TrFE-coated devices compared to those with LDH only.

These results highlight the synergistic benefits of combining LDH optimization with PVDF-TrFE loading, presenting a promising strategy for the development of flexible, high-performance energy harvesters for wearable and self-powered sensor applications.

References

[1] Fan, F.-R., Tian, Z.-Q., & Wang, Z. L. (2012). Flexible triboelectric generator. Nano Energy, 1(2), 328–334.

[2] Nguyen, T. M. T., et al. (2018). Enhanced Output Performance of Nanogenerator Based on Composite of PVDF and Zn:Al LDHs. Trans. Electr. Electron. Mater., 19, 403–411.

[3] Park, D., et al. (2021). Performance enhancement of flexible polymer triboelectric generator. Applied Sciences, 11(3), 1284.

Abstract

Developing polymer-assisted advanced materials for multifunctional energy storage and sensing platforms offers a viable path to address future energy demands and associated economic constraints. In this context, inverse spinel-structured NiMn₂O₄ has gained attention as a next-generation electrode material due to its high energy density, superior power delivery, and robust cycling stability. The incorporation of polyvinylpyrrolidone (PVP) as a polymeric surfactant during hydrothermal synthesis plays a pivotal role in tailoring the material's nanoscale architecture. PVP not only modulates nucleation and growth to achieve a mixed morphology of nanocubes and nanoflakes, thereby optimizing the surface-to-volume ratio, but also facilitates a shift from diffusion-controlled to surface-driven capacitive behavior. This transition significantly improves charge transport dynamics, energy density, and structural durability. The resulting electrodes deliver a high specific capacitance of 816 F g^-1 at 1 A g^-1 and retain excellent cyclic stability over 5000 cycles in 1 M KOH. The assembled asymmetric supercapacitor (ASC) device demonstrates 96% capacitance retention after 10,000 cycles, delivering an energy density of 8.8 Wh kg^-1 at 6400 W kg^-1 and reaching a peak energy density of 36.55 Wh kg^-1 at 400 W kg^-1. Complementary density functional theory (DFT) analysis provides insights into the polymer-modulated electronic structure and redox behavior. In addition, the non-enzymatic NiMn4/GCE-based H₂O₂ sensor showcases excellent sensitivity, a low detection limit, and high selectivity against various biological interferences, demonstrating the polymer-engineered NiMn₂O₄’s dual functionality in sustainable energy and biosensing applications.

The current study investigated the effects of increasing the concentration of CuO NPs on the performance of biocomposite films derived from taro starch and Aloe vera gel. The CuO NPs synthesized through chemical co-precipitation and calcification were mixed with taro starch and aloe vera gel to obtain biodegradable bio-nanocomposites films. The glycerol, biopolymers and the CuO NPs were mixed and cast and dried in the oven to create uniform films. The bionanocomposite film was characterized by optical, mechanical, physical, chemical, morphological analysis, antimicrobial and antioxidant properties. Results show that as the concentration of CuO NP increases, the film's opacity also increases as the film absorbs more light. Although the optimum percentage of CuO NPs enhanced the film thickness, the tensile strength decreased at higher concentrations (1. 5% and 2. 0%)
because of agglomeration. Moreover, adding the CuO NPs to the biopolymer matrix had no new chemical interaction. However, the agglomeration was caused by physical factors. The glass transition temperature (Tg) and melting point temperature (Tm) rise with increasing CuO NPs, indicating a significant relationship between CuO NPs and the biopolymer film. The antibacterial activity of the film raised with increasing CuO concentration against all bacterial strains due to the leaching of copper ions. There was no considerable impact on the antioxidant property of the bio-nanocomposite film. Therefore, Copper Oxide nanoparticles (CuO NPs) have benefits such as a high light barrier effect, possible antibacterial properties, and possibly enhanced thermal stability, making them suitable for active food packaging applications.

Illite, a naturally abundant clay, was modified with iron to enhance its catalytic efficiency and incorporated into a chitosan matrix to create a composite catalyst for environmental remediation. The synthesis involved impregnating illite with 10% (w/w) iron, followed by integration into a chitosan polymer using ionotropic gelation. The resulting composite was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analysis. Characterization confirmed the successful incorporation of iron into the illite structure and its homogeneous dispersion in the chitosan matrix, yielding a porous material with a surface area of 85 m²/g.

The composite's catalytic activity was tested on the degradation of a model organic pollutant (50 mg/L concentration) under optimized conditions of pH 4.5, temperature 50°C, and a catalyst dosage of 1 g/L. The results showed an exceptional degradation rate of 98.5% within 90 minutes of reaction time. Reusability tests demonstrated that the composite retained 92% of its initial catalytic activity after five cycles, indicating excellent stability and reusability.

These findings establish the iron-modified illite-chitosan composite as a highly efficient and sustainable catalyst for environmental applications. Its high degradation efficiency, coupled with economic and environmental benefits, makes it a promising candidate for large-scale pollutant degradation and wastewater treatment processes.

The microwave (MW)-assisted method for the synthesis of nanoparticles has been studied for a long time due to its rapid synthesis and lower consumption of energy, ultimately reducing cost. In this study, we synthesized for the first time, monodisperse iron-oxide nanocubes (IONCs) by MW-assisted method using an environmentally friendly precursor and organic solvents [1]. The cubic shape of iron-oxide nanoparticles provides superior magnetic properties over the spherical counterparts and, due to this, can be exploited in magnetic hyperthermia (MHT) applications to generate local heating effects under the influence of alternating magnetic fields (AMF) to kill cancer cells. However, IONCs synthesized in organic solvents must be transferred to water using polymers or ligands for solubility, dispersity, and to prevent agglomeration in biological fluids. Therefore, this study explored different coating strategies to transfer organic synthesized IONCs into water. This was done by coating the IONCs with different polymers and ligands, including dopamine-poly(isobutylene-alt-maleic anhydride)-poly(ethylene glycol), poly(maleic anhydride-alt-1-octadecene), gallol-derived ligands, and cetyltrimethylammonium bromide. The coated IONCs in water were further characterized via transmission electron microscopy (TEM), dynamic light scattering (DLS), and agarose gel electrophoresis. The magnetic properties of the coated IONCs were also evaluated by conducting specific absorption rate (SAR) measurements. By comparing the SAR values of the differently coated IONCs, it emerges the critical role of the coatings on the magnetic heating efficiencies of the resulting nanoparticles, therefore suggesting the choice of the hydrophilic coating as a critical parameter to further optimize the magnetic hyperthermia treatment.

[1] Mekseriwattana W., et al. Advanced Functional Materials, 2024, 2413514. doi.org/10.1002/adfm.202413514.

Abstract:

The crystallization behavior of polyethylene terephthalate (PET) and PET/Thermotropic liquid crystalline polymer (TLCP) composites was analyzed under isothermal conditions using calorimetric kinetic data, with thermodynamic parameters derived from the Lauritzen–Hoffman (L-H) model. The crystal growth process, dominated by secondary nucleation, deviates from simple spherulitic radial growth, instead reflecting a complex interplay of nucleation and lamellar growth phenomena. The temperature dependence of the linear crystal growth rate (G) follows a biexponential form as per the L-H relation, integrating both segmental transport and thermodynamic driving forces. Through kinetic modelling, values of nucleation constants (Kg), pre-exponential growth factors (Gâ‚€), and surface free energies (σ and σâ‚‘) were obtained. The analysis confirmed crystallization in Regime II across all compositions and temperatures studied (195–210°C), characterized by a chain-folding mechanism where growth occurs on pre-existing crystalline substrates. The substrate length (L), estimated via the Lauritzen Z test, increases with TLCP content and crystallization temperature, indicating enhanced nucleation and hindered chain folding in composites. PET/TLCP blends exhibited higher fold surface energy and work of chain folding compared to neat PET, revealing the inhibitory effect of TLCP on PET crystallization kinetics. These findings offer a comprehensive understanding of the crystallization regime transitions and underlying thermodynamics in PET/TLCP systems.