Search Results (405)

Microplastics (MP) are emerging pollutants found in the Veracruz Reef System National Park (PNSAV). They are widely distributed in the aquatic environment and are ingested by organisms either accidentally or because they are mistaken for food. In this article, the author analyses the physicochemical characteristics of reef sediments using visual identification, Nile Red (NR), scanning electron microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) of microplastics found in sediments adjacent to reefs; this allowed us to determine their distribution within the PNSAV. A total of 687 microplastics per kilogram of dry sediment were quantified, including fibres (98.5%), films (1.4%), and fragments (0.01%). The predominant colour was transparent (60.2%), followed by blue (16%) and red (12%). Based on their MP distribution, the sites were classified into two groups: north and south. The sampling stations with the highest concentrations of MP are located in the group of reefs south of the PNSAV, with the Anegadilla Reef being the most affected station. SEM/EDS analyses revealed elemental spectra dominated by carbon and oxygen, which is consistent with the expected elemental composition of polymeric materials. Peaks of chlorine were detected in some MP particles, suggesting the possible presence of chlorinated polymers, such as polyvinyl chloride (PVC). In addition, elements such as titanium, silicon, and nickel were identified, which could be associated with inorganic particles adhering to the surface or with additives commonly incorporated during the manufacture of plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). The presence of elements such as titanium and nickel were detected; these are found in additives used in the manufacturing of polymers. Full article

Plastic pollution in terrestrial and freshwater environments and its accumulation along food chains has been poorly studied in birds. In this paper we reported evidence of microplastic (MP) contamination in pellets collected in rural and urban sites for a set of species: common kestrel, Falco tinnunculus; great cormorant, Phalacrocorax carbo; barn owl, Tyto alba; little owl, Athene noctua; long-eared owl, Asio otus; Eurasian scops owl, Otus scops; European bee-eater, Merops apiaster; and little egret, Egretta garzetta. A total of 559 pellets were collected and analyzed; among them, 78 microplastics were found on 77 pellets (13.8% compared to the total number of pellets sampled). The following polymers were recorded: polyvinylchloride (PVC), polyethylene (PE), expanded polyester (EPS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester (PES), polymethyl acrylate (PMA), rubber, and starch-based biopolymer. We found significantly higher MP frequency in the most anthropized site. Pellets with the highest number of microplastics were those produced by Falco tinnunculus, Asio otus, and Tyto alba, with 30.0%, 29.6%, and 27.1%, respectively. Of a total sample of 78 MP items, 59.0% are represented by fibers, 23.1% by fragments and 17.9% by films. Among the microplastics, fragments of balloons (in a remote area) and biopolymer shopping bags were found. Our results suggest that pellet analysis may represent a cost-effective method for monitoring MP contamination along food chains in terrestrial ecosystems. Full article

Copper (Cu) thin films and meshes on polyethylene terephthalate (PET) substrates are promising flexible transparent conductive electrodes (TCEs), yet their practical use is limited by insufficient interfacial adhesion and poor oxidative stability on inert polymer substrates. This work addresses these issues via a synergistic strategy of interfacial layer engineering and maskless laser lithography-based aperiodic mesh patterning, systematically comparing ceramic (Al₂O₃) and metallic (NiCr) interfacial layers for PET-supported Cu films and fabricating Linear/Sinusoidal aperiodic Cu meshes with tailored performance. Magnetron sputtering shows that Ar plasma-activated NiCr interfacial layers form a gradient-alloyed interface with Cu via interdiffusion, achieving 5B-level adhesion, mitigating bending-induced stress concentration, and enhancing damp-heat resistance (85 °C/85% RH) by suppressing oxidation—outperforming brittle Al₂O₃ layers. Patterning the optimized Cu/NiCr/PET structure into micrometer-scale meshes yields a Linear design with superior optoelectronic performance (~10.8 Ω/sq sheet resistance, >87% transmittance at 550 nm) and a Sinusoidal design with enhanced bending robustness via stress delocalization. Microstructural and elemental analyses clarify the NiCr layer’s interfacial toughening and anti-oxidation mechanisms. Practical validation in flexible transparent heaters demonstrates rapid thermal response and >20 h continuous operational stability. This study provides a scalable design strategy for high-performance PET-supported Cu meshes, offering insights for interface and structural optimization of flexible metallic TCEs for next-generation optoelectronics. Full article

This study examines the nature of enzymatic degradation of polyethylene terephthalate (PET) films mediated by a novel recombinant LCC^ICCG PETase enzyme preparation based on P. verruculosum fungus. The investigation was conducted using amorphous PET samples and PET samples with varying degrees of crystallinity as substrates for PETase-catalyzed hydrolysis under different temperature and pH conditions. Mechanical testing revealed that enzymatic treatment reduced the yield stress by 20–25%, tensile strength by approximately twofold, and elongation at break by 5–10 times, while the deformation mechanism remained unchanged. Enzymatic degradation under acidic conditions was ineffective, whereas increasing the pH to 9–10 markedly accelerated PET degradation and the associated deterioration of mechanical properties. Thermal analysis (TGA, DSC) and microscopy (optical and scanning electron microscopy) demonstrated that degradation was localized at the polymer surface, leading to the formation of cavities, cracks, and submicron-sized pores rather than bulk material disintegration. An inverse correlation was observed between PET crystallinity and susceptibility to enzymatic degradation: samples with crystallinity below 13% could be almost completely degraded, whereas samples with crystallinity above 30% exhibited little or no measurable weight loss over the same period. Low-crystallinity PET underwent rapid degradation accompanied by a transient increase in crystallinity, while highly crystalline PET primarily accumulated surface defects that nevertheless caused a substantial loss of mechanical strength. Consequently, the experimental data obtained in this study provide useful information for understanding PET degradation and for future studies on enzymatic PET recycling. The systematization of feedstock characteristics and the elucidated patterns of enzymatic degradation will enable optimization of pretreatment, enzymatic hydrolysis, and monomer recovery process parameters, thereby facilitating the eventual production of secondary raw materials. Full article

Celiac patients require strict avoidance of gliadin, the primary immunotoxic component of gluten, making sensitive detection essential for food safety. A label-free and reagentless capacitive aptasensor for gliadin detection was developed using an aminated polyethylene terephthalate (PET) thin film as both an insulating layer and functionalization platform. The PET surface was modified via ethylenediamine-mediated aminolysis, enabling covalent immobilization of 5′-NH₂-modified gliadin aptamers through glutaraldehyde crosslinking. Under optimized conditions (23 µm initial PET thickness and 10 µM aptamer), the sensor showed a linear response from 10 to 500 µg/mL gliadin (R² = 0.9792), with a detection limit of 6.0 µg/mL, equivalent to 12 ppm gluten, which is well below the regulatory threshold of 20 ppm for gluten-free labeling. The aptasensor showed excellent correlation with commercial ELISA for 20 gluten-containing soy sauce samples (R² = 0.926) and spike recoveries of 91.7–105.7% in two gluten-free products. Efficient regeneration was achieved with 25 mM arginine (pH 9.0), retaining >80% activity after six cycles. This simple, low-cost, and reusable platform relies solely on a single PET thin film as consumable in a custom-built system with lab-friendly aminolysis conditions. It substantially lowers barriers to functionalized insulating layer fabrication, the primary challenge in capacitive aptasensor development, providing a promising method for on-site gliadin monitoring in gluten-free food safety applications. Full article

A broadband method for measuring the complex permeability of thin magnetic films using a short-circuited microstrip fixture is presented. The method is based on full one-port offset-short calibration implemented directly in the fixture with a movable shorting wall, reducing sensitivity to coaxial-to-strip transition imperfections and eliminating the need for its precise optimization. Field-dependent normalization to the empty fixture reduces systematic errors from the external magnetic field, and a correction for residual saturated permeability improves retrieval accuracy. The method was validated on Co, supermalloy, and FeCo films on flexible PET substrates. Retrieved spectra agreed well with reference coaxial data and with the spectrum reconstructed from static magnetic measurements. In the present implementation, broadband spectra were obtained from 0.1 to 20 GHz with no significant systematic distortion, indicating that the proposed approach is suitable for accurate broadband characterization of thin magnetic films without reference standards or precise optimization of the coaxial-to-strip transition. Full article

Flexible transparent conductive films (TCFs) and their applications have attracted extensive interest. Silver nanowires (AgNWs) have been explored to replace conventional indium tin oxide (ITO) due to their high optical transmittance and superior electrical conductivity. Nevertheless, AgNWs tend to oxidize under ambient conditions, which weakens the conductive network and limits long-term performance. Spraying reduced graphene oxide (rGO) can stabilize the conductive network and inhibit oxidation, thereby enhancing the overall properties of the films. In this work, rGO/AgNW/PET TCFs were prepared using a spray-coating approach. The transmittance of the rGO/AgNW/PET TCFs was measured at 77% at 550 nm, accompanied by a sheet resistance of 6.8 Ω/sq. The films achieved the surface temperature of 95 °C at 6 V with stable operation while also achieving an electromagnetic interference shielding effectiveness of 27 dB. This structural design improves both performance and stability, offering great potential for flexible TCFs in advanced optoelectronic applications. Full article

Radio frequency identification (RFID) technology has been widely adopted in a variety of practical applications. Usually, the size of a passive tag antenna largely determines the read performance of tag. However, excessively large tag antennas can hinder their practical application and a tag that is too small has poor performance. In this paper, a compact, flexible and corrosion-resistant folding dipole tag antenna is proposed, which has a geometrical dimension of 24 mm × 13 mm (0.074${\mathsf{\lambda }}_0\times 0.040{\mathsf{\lambda }}_0$). It is designed on only one surface of a flexible polyethylene terephthalate (PET) substrate, which can be folded. The paper proposes a single-sided laser-patterned GAF/PET flexible RFID tag that is mechanically folded to form a backside dipole arm without vias, targeting compact and corrosion-resistant UHF RFID operation. Changing the size of the folding arm can effectively adjust the resonant frequency and impedance of the tag antenna. A stepped radiation arm is used to extend the current path and lower the resonance frequency. The capacitance and inductance effects introduced by loading a T match for reducing the resonant frequency of the tag to the useful UHF RFID band. Finally, it can achieve a power transfer coefficient of 99.9% and exhibit high impedance matching between the tag antenna and the chip. The proposed tag antenna uses graphene-assembled film (GAF) as its conductor material. Thanks to the physicochemical properties of GAF, the proposed tag antenna maintains stable radiation performance even after prolonged exposure to acidic (5 wt%), alkaline (5 wt%), and salt (5 wt%) corrosion, as well as more than 1000 mechanical bending cycles. When the EIRP of the reader is 2.2 W, the maximum read range of the tag in the 800–1000 MHz is 1.38 m. Full article

This study provides the first comprehensive assessment of microplastic (MP) contamination within oyster bed ecosystems of the Kingdom of Bahrain. Sediment, water, and oyster samples were collected from six sites representing diverse environmental conditions. Raman spectroscopy identified the presence of 12 distinct polymer types, with polypropylene (PP), polyurethane (PU), poly(ethylene terephthalate)/diamine/multi-walled carbon nanotube (PET/diamine/MWCNT), and fluorinated ethylene propylene (FEP) being the most prevalent. MPs occurred predominantly as fragments, films, and pellets, with black being the most common color across all matrices. MP abundances ranged from 750 to 1850 MPs/kg dry weight in sediments, 2100–9600 MPs/L in water, and 1.78–5.25 MPs/individual in oysters, with particles (<50 µm) most frequent in oyster tissues. Although spatial variation was evident across regions, detected polymers included types associated with known ecotoxicological risks. No significant correlation was observed between sediment grain size and MP abundance, suggesting that additional hydrodynamic or anthropogenic factors may influence MP distribution. Overall, this study provides critical baseline data on MP contamination in Bahrain’s marine environments and highlights the need for continued monitoring to assess potential risks to marine ecosystems and seafood safety. It also contributes to the limited understanding of MPs in the Arabian Gulf, informing future monitoring, conservation and policy initiatives that support long-term environmental sustainability. Full article

The effects of RF plasma treatments using different gases (Ar, O₂, and N₂) and processing parameters on the surface wettability of polyethylene terephthalate (PET) films were systematically investigated. Atomic force microscopy (AFM) and X–ray photoelectron spectroscopy (XPS) were employed to characterize the evolution of surface topography and chemical composition. While all treatments enhanced hydrophilicity, the magnitude of improvement and the governing mechanisms were gas-dependent. Among them, O₂ plasma treatment exhibited the most pronounced effect: under optimal conditions (20 W, 80 s), the water contact angle (WCA) was reduced to 3.7°, indicating a superhydrophilic surface. This enhancement was primarily attributed to a substantial increase in surface oxygen content (O/C ratio) and the incorporation of strongly polar oxygen-containing functional groups, such as C=O and COOH. N₂ plasma offered moderate improvement via nitrogen-containing groups, while non-reactive Ar plasma relied primarily on physical etching, yielding the smallest enhancement. Analysis revealed that wettability evolution was dominated by increased polar surface energy from chemical functionalization, with surface roughness playing a synergistic role. These results demonstrate that optimizing plasma gas and parameters effectively controls PET wettability through the coupled regulation of surface chemistry and topography. Full article

High-temperature sintered conductive silver paste serves as a critical material in the fabrication of electronic components, with its performance directly influencing device reliability and integration density. In this work, conductive silver paste was prepared via a ball milling method by dispersing silver powder (conductive filler), glass powder (binder), and ethyl cellulose (EC, thickener) in an organic carrier composed of α-terpineol, diethylene glycol butyl ether acetate (DBA), and dimethyl phthalate (DMP) at specific ratios. The effects of the formulation composition and preparation process on the rheological properties of the paste as well as the electrical and mechanical properties of the resulting films were systematically investigated. The results indicated that sintering time and temperature exerted regular effects on the resistance of the silver paste; ball milling speed and duration influenced the particle size distribution, thereby affecting the resistance behavior; thixotropy significantly impacted the resistance characteristics. Under optimal conditions, where the organic carrier consisted of α-terpineol, DBA, and DMP at a ratio of 6:3:1, with 30 wt.% silver powder, 18 wt.% glass powder, and 4 wt.% EC, combined with a sintering temperature of 500 °C for 50–60 min, a ball milling speed of 500–600 r/min, and a ball milling time of approximately 1.5 h, the obtained silver paste exhibited pronounced shear-thinning behavior and excellent thixotropy, indicating favorable processability. The corresponding silver paste film demonstrated the lowest resistivity, superior bending resistance, and good adhesion to both PET and glass substrates. This study provides valuable insights for the design and preparation of high-performance, high-temperature sintered conductive silver pastes. Full article

Nanoimprint lithography (NIL) is highly dependent on imprinted film as a pattern-transfer medium. This paper systematically reviews the research progress of imprint film materials for NIL. Firstly, polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyvinyl alcohol (PVA) and other single-polymer films are discussed, and their respective advantages (such as low surface energy, high optical transparency, water solubility) and inherent limitations (elastic deformation, demolding difficulties, humidity sensitivity)) are summarized. In order to overcome the above contradiction, researchers developed a composite imprint film structure, including an elastomer–rigid bilayer template and sandwich structure film, which achieved high resolution, conformal contact and facile demolding characteristics through mechanical function decoupling. At the same time, the emerging polymer/transparent electrode composite system (such as AgNWs/PVA, AgNWs/PDMS) gives the film active functions such as self-heating and antistatic ones, which effectively solves the key challenges in thermal management and electrostatic control. This paper comprehensively presents the evolution path from single-material to multi-functional composites, and provides guidance for the design of advanced imprint film for high precision, high reliability and large-scale NIL applications. Full article

As a sustainable alternative to petroleum-based plastics, psyllium gum, a natural hydrocolloid from Plantago ovata seeds, is reviewed for its application in packaging. This review focuses on the material properties of psyllium gum, including its film-forming capacity, water-binding capacity of 12–15 g/g, and rheological behavior (consistency index K = 10–50 Pa·sⁿ, flow behavior index n = 0.3–0.6), which are critical for packaging applications. We discuss how its performance can be enhanced through interactions with plasticizers, cross-linking agents, and blending with other biopolymers (e.g., polyvinyl alcohol and starch), as well as through nanocomposite reinforcement, to improve mechanical strength (tensile strength 5–15 MPa in native films; up to 48 MPa in thermoplastic starch composites), and barrier properties (e.g., oxygen permeability < 0.001 g/m² s). The review also provides a comparative analysis of psyllium-based films with other polysaccharide films and discusses the environmental benefits, such as a lower carbon footprint (GWP ≈ 1.2 kg CO₂-eq/kg) compared to PET (≈3.0 kg CO₂-eq/kg). Key challenges, including moisture sensitivity (equilibrium moisture content ~25% at 75% RH), raw material molecular-weight variability (±20%), and scalability, are outlined, along with future research directions, such as enzymatic extraction and the development of water-resistant, compostable formulations aimed at advancing psyllium gum toward viable next-generation sustainable food packaging materials. Full article

The development of effective fluorescent probes for the detection of acids and bases, both in solution and in the solid state, is of particular interest worldwide, due to the possibility of preventing hazardous consequences for human health and the environment. In the present work, the synthesis of a 1,8-naphthalimide derivative, designed as a “fluorophore-receptor₁-spacer-receptor₂” model, is considered. The compound contains two receptors for analytes in one molecule and can operate as a fluorescent probe via PET and ICT mechanisms. The photophysical behavior of the synthesized derivative in solution, on strip paper, and in thin film was investigated. It was found that the transition from acidic to alkaline medium in solution is associated with a change in color that is visible with the naked eye (yellow–orange-red–blue). The change in fluorescence, both in solution and spread on a supporting surface (strip paper and thin film), can be spectrophotometrically observed. The influence of various volatile acids on the sensing activity of the synthesized compound in solution and deposited on a solid support was investigated. It was found that with increasing acid strength, the fluorescence intensity increases. The strip paper and thin film obtained with the synthesized compound show reversible switching between the “off” and “on” states of fluorescence. The strip paper exhibited good cycling under acid–base vapor stimulation. The results obtained demonstrate the possibility of application of the synthesized compound as a colorimetric and fluorescent probe for determination of pH in solution, and detection of acids, bases, and their vapors in indoor and outdoor residential and industrial premises, as well as in the environment. Full article

Mixed-halide perovskite solar cells with the composition Cs_0.1(MA_0.17FA_0.83)_0.9Pb(I_0.83Br_0.17)₃ were fabricated obtaining solar cells as glass/ITO/SnO₂/triple-cation perovskite/HTL/Au, and subsequently used as photoanodes for efficient solar-driven water splitting by attaching commercial catalytic nickel foils to the Au back-contact pads of solar cells. To enable operation in alkaline media, the devices were encapsulated using commercial PET–EVA multilayer films, providing an effective barrier while leaving the Ni foils exposed as the electrochemically active interface. Two operating configurations were investigated and compared: (i) an outside configuration, where the perovskite device powered the external electrochemical cell, and (ii) an immersed configuration, in which the encapsulated perovskite solar cell was directly integrated, together with the Ni catalyst, into the electrolyte. In both configurations, the onset potential for the oxygen evolution reaction shifted from ~1.32 V vs. RHE, when the Ni electrode was not powered by the perovskite solar cell, to ~0.34 V vs. RHE, when the perovskite device powered the Ni foil for both immersed and outside configurations. The immersed configuration delivered the highest performance, achieving a maximum Applied Bias Photon-to-Current Efficiency of ~20% under AM 1.5 G illumination (100 mW cm⁻²), among the highest values reported for perovskite-based photoanodes. Importantly, the enhanced performance does not arise from changes in catalyst composition or direct semiconductor–electrolyte interaction, but from improved photovoltage delivery and reduced resistive losses enabled by the integrated device architecture. These results demonstrate that device architecture is a key factor in controlling photovoltage utilization and charge-transfer kinetics, providing a viable strategy for efficient and scalable perovskite-based photoelectrochemical systems. Full article