Three-layer Film Research Articles

Research on the Influence of the Type and Content of Regranulate on Selected Mechanical Properties of the Three-Layer Polyethylene Film Obtained by Blown Film Extrusion

Research on the Influence of the Type and Content of Regranulate on Selected Mechanical Properties of the Three-Layer Polyethylene Film Obtained by Blown Film Extrusion

Preparation of gelatin/gelatin-dextran/gelatin-based three-layer films with cinnamaldehyde and α-tocopherol for scallop (Patinopecten yessoensis) adductor muscle preservation

In this study, three-layer films based on gelatin/gelatin-dextran/gelatin with different concentrations of functional fillers (cinnamaldehyde and α-tocopherol) were fabricated by using the layer-by-layer casting method to preserve refrigerated scallop adductor muscle. The films demonstrated excellent bonding, with functional fillers creating a porous cross-section, a slightly rough surface, and increased hydrophobicity while maintaining thermal stability. The crystallinity, water contact angle, thickness, opacity, antioxidant activity, and antibacterial activity of the films were increased, while the water vapor permeability and mechanical properties were decreased with increasing concentrations of the functional fillers. The film with 1.2% active fillers showed over 82% free radical scavenging activity and significant inhibition zones (24.7 ± 1.2 to 43.9 ± 1.8 mm) against five foodborne pathogens and spoilage bacteria. Both cinnamaldehyde and α-tocopherol demonstrated controlled release properties in four food simulants, with the maximum release and minimum release times observed in 95% ethanol (9.0 h) and distilled water (2.0 h), respectively. Overall, the introduction of 1.2% of active fillers into the films significantly enhanced the chemical and microbiological stability of refrigerated scallops and prolonged their shelf life by 6 days. Furthermore, the developed films showed excellent controlled release, antibacterial, and antioxidant properties, making them potential candidates for preserving seafood.

Effect of lanthanum on the structure, properties and high-temperature oxidation patterns of the (Hf,Ta)B2–SiC ceramics

This paper focuses on the kinetics and the mechanism of oxidation (at 1650°C) of the ceramics based on the (Hf0.8Ta0.2)B2, β-SiC and LaF3 (0 and 3.5 wt%) phases fabricated by a combination of self-propagating high-temperature synthesis (SHS) and hot pressing (HP). The physicomechanical and thermophysical properties of the ceramics were determined. The effect of doping with lanthanum on the kinetics and mechanism of oxidation as well as the structural and morphological features of the resulting oxide layers after efficiency of their protective action was analyzed. The evolutionary changes in the structure were studied: the formation of a three-layered heterogeneous oxide film, modification of borosilicate glass with Hf4+, Ta5+ and La3+ cations, formation of Hf4+-doped La1/3TaO3 globules followed by their growth via the Ostwald ripening mechanism, generation and oxidation of the secondary TaB2 phase, significant reduction of the content of the HfSiO4 phase, etc. Doping the ceramics with lanthanum was shown to exhibit a negative effect on high-temperature oxidation resistance, and the main reasons for that were analyzed.

Ultra-fine nano-crystalline optimize electrostatic energy storage

Grain size pays a crucial role in the properties of ferroelectrics and dielectrics. Reducing the grain size is considered to be an effective mean for enhancing dielectric energy storage. In this work, high recovered energy storage density and efficiency were achieved in three-layered Aurivillius thin films by ultra-fine grain nano-crystalline engineering. The ultra-low remanent polarization can be attributed to the emergence of polar nano-regions due to the disruption of macroscopic continuity of ferroelectric domains by ultra-fine nano-grains. At the same time, all thin films have high dielectric breakdown strength due to the presence of extremely high grain boundary density. Thus, a high recovered energy storage density of 71 J/cm3 and an efficiency of 76% were achieved, and the thin film capacitors show good fatigue endurance and temperature stability. The results suggest that ultra-fine nano-crystalline engineering can expand the application of traditional ferroelectric thin films in energy storage devices.

Dynamic Wavelength-Selective Diffraction and Absorption with Direct-Patterned Hydrogel Metagrating.

Hydrogel nanophotonic devices exhibit attractive tunable capabilities in structural coloration and optical display. However, current hydrogel-based tunable strategies are mostly based on a single physical mechanism, and it remains a challenge to merge multiple mechanisms for active devices with integrated functionalities. Here, a hydrogel metagrating combining Fabry-Pérot (FP) resonance and diffraction effects is proposed for achieving tunable absorption and dynamic wavelength-selective beam steering. Through exploiting hydrogel shrinkage under electron-beam exposure, a hydrogel nanocavity composed of Ag/Hydrogel/Ag three-layer films can be directly printed with arbitrary patterns, enabling the direct-pattering technique of metagrating. The hydrogel nanocavity performs as an FP-type absorber, and its absorption peak rapidly shifts with humidity variation due to the hydrogel layer scaling. The response speed is <320ms, and the absorption peak shift range is >150nm. It is further demonstrated that the hydrogel metagrating exclusively deflects light at the resonance wavelength, and its operating wavelength can be actively switched by regulating ambient humidity. The proposed tunable hydrogel metagrating can promote new technologies of tunable metasurfaces for optical filtering, gas sensing, and optical imaging.

Three-layered films enable efficient passive radiation cooling of buildings

Abstract To address the excessive energy consumption of building cooling, the coverage of passive radiation cooling materials on the surface of buildings can effectively save the global refrigeration power resources and reduce the greenhouse gas emissions generated by refrigeration equipment. In this work, passive radiation hydrophobic fabric cooling materials with three functional layers (i.e., top polydimethylsiloxane [PDMS] film layer for solar emissivity, middle polymethylmethacrylate [PMMA] film layer for solar reflectivity, and bottom cotton fabric layer for support) were prepared. This passive radiation cooling material with optimized thickness of PDMS (1.5 mm) and PMMA (3.5 mm) have a rich uneven filament structure and ideal internal bonding structure, which enabled 94% of solar reflectivity and 93.4% of atmospheric window emissivity (8–14 μm). Top layer of the composite film was hydrophobic (a contact angle of 117°) and allowed the rolling of water droplets to remove most of the surface dust. Moreover, these composites presented an excellent cooling of 7.7–15.0°C in the outdoor real cooling test. For medium-sized houses, the roof covered with composite was expected to reduce the emission CO2 by 17% every year. The findings of this work indicated that the prepared three-layered radiation cooling materials have great potentials in thermal energy storage buildings.

Poly (lactic acid)/Poly (butylene adipate-co-terephthalate) films with simultaneous high oxygen barrier and fast degradation properties

Although poly (lactic acid) (PLA) is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films, the barrier properties of PLA films are still insufficient for high-barrier packaging applications. In this study, oxygen scavenger hydroxyl-terminated polybutadiene (HTPB) and cobalt salt catalyst were incorporated into the PLA/poly (butylene adipate-co-terephthalate) (PLA/PBAT), followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films. The oxygen permeability coefficient of the composite film combined with 6 wt% oxygen scavenger and 0.4 wt% catalyst was decreased significantly from 377.00 cc·mil·m−2·day−1·0.1 MPa−1 to 0.98 cc·mil·m−2·day−1·0.1 MPa−1, showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film. Meanwhile, the degradation behavior of the composite film was also accelerated, exhibiting a mass loss of nearly 60% of the original mass after seven days of degradation in an alkaline environment, whereas PLA/PBAT composite film only showed a mass loss of 32%. This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior, which has great potential for high-demanding green chemistry packaging industries, including food, agricultural, and military packaging.

Development of polyvinyl alcohol based active inner coating reinforced with chlorogenic acid and functionalized layered clay for food packaging

Food packaging is developing towards more environmentally friendly polymer matrix and superior active functions. In this study, polyvinyl alcohol (PVA) based active coating incorporating chlorogenic acid (CGA) and CGA functionalized layered clay (LDHs@CGA) was applied to construct polylactic acid (PLA) three-layer active films on fully biodegradable PLA base film. The results indicated that PVA based active coating using dual coating technology (LDHs@CGA/PVA + CGA/PVA) had no visible interface and a uniform thickness, ranging from 4 to 5 μm. When the amount of LDHs@CGA was 1 wt%, the release of CGA in the active intermediate layer (CGA/PVA coating) was limited due to the natural barrier of LDHs@CGA in the controlled release layer (LDHs@CGA/PVA coating), resulting in a decrease in active functions. When the amount of LDHs@CGA reached 3 wt%, the antioxidant (DPPH method), antibacterial (Escherichia coli), and UV absorption (at 335 nm) reached 85.6 %, 87.2 %, and 73.2 %, respectively. This was because in addition to CGA as the main active substance, sufficient amounts of LDHs@CGA can also serve as secondary active substance to supplement the release of CGA. Meanwhile, the addition of LDHs@CGA could significantly improve the gas barrier properties of PVA based active coating, and the barrier to oxygen was much higher than that to water vapor. This study proposes a method of constructing PLA three-layer active films by coating with PVA based active inner coating, which can more effectively and stably exert the active functions for food packaging applications.

Development of PBS/Nano Composite PHB-Based Multilayer Blown Films with Enhanced Properties for Food Packaging Applications.

Biobased and biodegradable plastics have emerged as promising alternatives to conventional plastics offering the potential to reduce environmental impacts while promoting sustainability. This study focuses on the production of multilayer blown films with enhanced functional properties suitable for food packaging applications. Films were developed through co-extrusion in a three-layer film configuration, with Polybutylene Succinate (PBS) and Polybutylene Succinate Adipate (PBSA) as the external and internal layers, respectively. The functional layer consisted of Polyhydroxybutyrate (PHB) enhanced with nanoclays Cloisite® 30B at varying weight ratios. Films were also processed by manipulating the extruder screw speed of the functional layer to investigate its impact on the functional properties. Rheology, mechanical strength, and barrier performance were characterised to establish correlations between processing conditions and functional layer blends (Cloisite® 30B/PHB) on the properties of the resultant films. Rheological test results indicated that the system with 5% Cloisite® had the best polymer/nanofiller matrix dispersion. Mechanical and permeability tests showed that by varying the process conditions (the alteration of the thickness of the functionalized layer) resulted in an improvement in mechanical and barrier properties. Furthermore, the addition of the nanofiller resulted in a stiffening of the film with a subsequent decrease in permeability to oxygen and water vapour.

High energy storage properties for dielectric composite by asymmetric three-layer films design

Polymer dielectrics are extensively studied for applications in electronics pulsed power systems owing to their excellent processability, high breakdown strength and low energy loss. To synergistically achieve high energy density and high discharge efficiency, we report an asymmetric three-layer all-polymer composite, which consists of a mixture of P(VDF-HFP) and P(St-MMA) as an intermediate layer sandwiched between a linear polymer P(St-MMA) dielectric layer and a nonlinear polymer P(VDF-HFP) dielectric layer. The results of the study showed that a high efficiency of 94.14 % and a high energy discharge density of 14.86 J/cm3 were achieved concurrently. In this case, the linear dielectric layer provides high energy efficiency, and the high energy density is provided by the nonlinear layer dielectric layer. In particular, the middle layer can effectively balance the electric field distribution, which improves the breakdown strength and increases the energy density. The structural design of asymmetric three-layer all-polymer films provides an effective way to realize high-performance dielectric energy storage materials.

Preparation of PEDOT flexible transparent conductive film by Solution shear method for OLEDs

In this work, the large-area poly 3,4-ethylenedioxythiophene (PEDOT: PSS) transparent conductive films (TCFs) were prepared by the solution shear method. These films exhibited excellent bendability, strong adhesion, superior uniformity, and high-light transmission. The optimum photoelectric figure of merit (FoM) of the films was 195.5, and the optimum photoelectric performance at a low sheet resistance (< 50 Ω/sq) was observed in the three-layer films, which was prepared at a dilution ratio of 2:1 and a shear rate of 1 mm/s, showing a thin-layer resistance of 34.7 Ω/sq, a transmittance of 93.2 %, an FoM of 151.9 and electrical conductivity of 2398.6 S/cm. The prepared films were used as the organic light-emitting diode (OLED) anode, and the large-area flexible green OLED device with good uniformity was obtained. The maximum current efficiency of the prepared large-area flexible OLED was 2.16 cd/A, reflecting the great potential of this solution-shear film in the field of flexible devices.

Properties and Characteristics of Fish Skin Gelatin-Based Three-Layer Film Developed with Bioplastics and Physalis Leaf Extract

Properties and Characteristics of Fish Skin Gelatin-Based Three-Layer Film Developed with Bioplastics and Physalis Leaf Extract

Multi-layer photothermal film inspired by polar bear fur for anti-icing and photothermal de-icing in cold environments

As climatic conditions worsen and time passes, icing becomes an unavoidable issue. Drawing inspiration from the thermal regulatory properties inherent in polar bear fur, we introduce a biomimetic three-layer film. This film comprises a hydrophobic shield, a photothermal conversion layer, and an insulating layer through electrospinning. The multilayered micro/nanostructure within this film amplifies its light absorption capabilities, achieving an average absorption rate of 96.27 % across wavelengths ranging from 200 to 2500 nm. Thanks to the insulation layer's thoughtful design, the film boasts high photothermal conversion efficiency. When exposed to solar radiation for 360 s at an ambient temperature of 20 °C, its surface temperature swiftly climbs to 98.3 ± 1.1 °C. The film's anti-icing capabilities are evidenced by the fact that a droplet of water takes 2964.7 s to freeze on its surface, which is approximately 118 times that of aluminum. Additionally, it demonstrates excellent photothermal de-icing performance, swiftly eliminating thick layers of ice or frost under sunlight. Moreover, this film maintains its anti-icing and hydrophobic qualities even after multiple icing and de-icing cycles, as well as durability testing. It also possesses self-cleaning properties. Given its outstanding performance, this film has tremendous potential for long-term outdoor anti-icing applications.

Microstructure of corrosion product film formed on aged WE43 alloy

A dense three-layer corrosion product film was formed on aged WE43 alloy in 3.5 wt.% NaCl solution. The microstructure of the film was analyzed in detail by TEM. The three-layer corrosion product film is composed of RE2O3, MgO layer doped with RE2O3 and Mg(OH)2 layer doped with RE2O3 from the inside to the outside. A large amount of rare earth oxide particles formed both by the outward oxidation of rare earth precipitates and rare earth elements, are the main reason for the formation of the corrosion film. The RE2O3 has the preferential orientation with ( 2-11) plane and [231] direction parallel to (002) plane and [ 1-1-0] direction of MgO, respectively. Thus, the rare earth oxide particles can fill the gap of porous MgO layer, and improve the compactness of the film. The inner RE2O3 layer and mixed layer of MgO and RE2O3 play an important role in the formation of the film. The compact inner film can prevent the corrosion medium from reacting with the Mg matrix.

Refining laser-induced dewetting for bimetallic Au–Pd nanoparticle synthesis on ZnO thin films: Optimizing fluence for substrate integrity

We report the fabrication of metal alloy Au–Pd nanoparticles on semiconductor thin film substrates (ZnO) by laser-induced dewetting. Employing a UV excimer laser, a single pulse was directed onto a three-layer film stack on a glass substrate: glass/ZnO/Au/Pd and glass/ZnO/Pd/Au. We simulated the temperature attained by the thin films enabling the prediction of energy thresholds required for melting the metal films but avoiding modifying the ZnO film. A specific range is reported of the pulse energy conducive to nanoparticle formation and the energy threshold required to modify the ZnO film beneath them. Depending on the pulse energy applied, the mean diameter of the nanoparticles varied from approximately 150 to around 70 nm. Notably, higher fluences resulted in smaller particles but also induced surface cracks in the ZnO film. Additionally, we observed a reduction in nanoparticle size with increased Pd content. Our results show that laser-induced dewetting can produce bimetallic alloy nanoparticles and, at the same time, ensure the preservation of the optical properties of the ZnO film. This approach opens avenues for tailoring material characteristics and expanding the range of applications of metal nanoparticles on semiconductor-based systems.

The use of supporting materials in the process of making food containers from a mixture of PLA-starch and testing the quality of the coating: A review

The fulfillment of the food packaging industry’s needs for the use of non-petrochemical, biodegradable plastics from renewable sources that are also economically viable can be achieved through the utilization of polylactic acid-starch (PLA-starch). However, the perceived limitations of PLA-starch in terms of long-term food packaging have prompted recent innovations in which research is conducted on supportive materials that extend the shelf life of food packaging while still considering the health value of the added substances. This innovation provides significant advantages in using more durable food packaging materials that do not have adverse effects on food and human health. The utilization of ferulic and cinnamic acid compounds has been studied to reduce the environmental impact of food packaging while extending the shelf life of food. A three-layer film of PLA/starch/PLA (PSP) was designed based on the complementary barrier properties of the polymers, resulting in a film system with improved barrier properties. Electrospinning was effective in producing fibrous mats that encapsulated the acids, while film spraying resulted in the formation of crystalline structures of the active compounds strongly adhered to the surface. The electrospinning- and spray-coated films exhibited effective inhibition against the growth of E. coli and L. innocua. The TPScf-PLAes blend showed good antioxidant capacity when used in meat packaging and reduced microbial counts during cold storage. Silane-doped bilayer films demonstrated higher thermal stability compared to PPS. Therefore, the bilayer films and supporting materials have significant potential to extend the shelf life of food, maintaining its quality and safety for a longer period.

Corrosion of Ni-based alloy coatings prepared by laser cladding in high-temperature chloride environment

Due to the complex incineration environment of waste incineration power generation boilers generates large amounts of acidic gases (such as Cl2 and HCl) and alkali metal chlorides (such as NaCl and KCl), leading to boiler corrosion failure. Herein, a new type of NiCrAlTi alloy coatings was deposited on 304 stainless steel surfaces by laser cladding technology. High-temperature corrosion experiments were then carried out at 650 °C for 64 h and the results were compared with those of traditional Inconel625 alloy coating. The high-temperature chloride corrosion mechanism and the corrosion resistance of alloy coatings were examined. The results revealed the decomposition of chlorides, such as HCl, NaCl, and KCl into Cl2 at high temperatures as the source of corrosion of high-temperature chlorides. The released C12 reacted with the metals present in the coating to form nonprotective metal chlorides. The low melting point and high vapor pressure of metal chlorides allowed their transition into a gaseous state to diffuse outward and oxidize into Cl2. In turn, the released Cl2 reacted with the metal to induce corrosion. During the corrosion process of NiCrAlTi alloy coating, a Cr depletion zone was induced, and a continuous Al2O3/TiO2/Cr2O3 three-layer protective film was formed on the coating surface, conducive to better alleviating the corrosion caused by the reaction between Cl2 passing through the film and the metal substrate. Under the conditions of this experiment, the corrosion resistance of NiCrAlTi alloy coating is 1.8 times that of the common material 304 stainless steel, and about 1.2 times that of Incon625 alloy coating. With the extension of the experiment, its corrosion resistance will be better. Overall, rich experimental data and theoretical guidance were provided for further research and development on high-temperature chloride corrosion-resistant alloys or coating materials for high-efficiency cost-effectiveness boilers.

Design, preparation, and property analysis of metal/dielectric multilayer film with wavelength selectivity

Metal/dielectric multilayer films have important applications in energy-saving glass, stealth materials, solar energy utilization and other fields. In the current study, the thickness of each layer of TiO2/Ag/TiO2/Ag/TiO2 film is optimized. The effects of the number of metal/dielectric multilayer films and the incident light angle on their optical properties were investigated. The TiO2/Ag/TiO2/Ag/TiO2 film was prepared by electron beam evaporation coating technology, and their reflectance and transmittance were measured. The measurement results show that the visible light transmittance (380–780 nm) of the film can achieve 68.7%, and the infrared reflectance (780–2500 nm) can reach 95.9%. Compared with the traditional dielectric/metal/dielectric three-layer film, the visible light transmittance of the film is higher, and the solar infrared reflectance is greatly improved. In the solar radiation band (280–2500 nm), the average error between the experimental reflectance and transmittance and the theoretical prediction results is less than 0.03. The distribution of electric and magnetic fields inside the film was simulated by finite-difference time-domain method. The simulation results show that the high visible light transmittance is due to the interference resonance of electromagnetic waves inside the film. Taking Shanghai as an example, under our calculation conditions, compared with ordinary SiO2 glass, TiO2/Ag/TiO2/Ag/TiO2 film can reduce the total energy consumption of buildings by 14.3% and refrigeration energy consumption by 17.2%.

Thermal Conductivity Switching in Pd-Catalyzed Gd and GdH2 Films Upon Gasochromic Hydrogenation and Dehydrogenation

Thermal conductivity switching in Pd-catalyzed Gd hydride films was investigated using in situ analyses of electrical, optical, structural, and thermophysical properties upon gasochromic hydrogenation/dehydrogenation at room temperature. These reactions allow the films to reversibly switch between the metallic (GdH2) phase in the hydrogenated state and the semiconductor (GdH3) phase in the dehydrogenated state. We fabricated three-layered films comprising Pd (5 nm)/Gd or GdH2 (300 nm)/Mo (100 nm) using DC magnetron sputtering using Pd, Gd, and Mo targets, respectively, on unheated synthetic quartz substrates. Ar or mixture of Ar + H2 (H2: 5 % to 50 %) gases were used for the deposition of the Gd or GdH2 films, respectively. The thermal conductivities of the Gd or GdH2 films were analyzed using in situ rear-heating/rear-detection type time-domain picosecond pulsed light heating thermoreflectance measurements by employing a gas mixture of N2/Ar and H2 (H2: 3 %) at 1 atm, which is below the explosive limit for hydrogen. The thermal conductivities of Gd and GdH2 films were measured for one and two hydro-/dehydrogenation cycles, respectively. The thermal switching ratios of the ON state thermal conductivity to the OFF state thermal conductivity were 6.4 and 2.9–5.4 for the Gd film and the GdH2 (H2: 5 %–50 %) films, respectively. The thermal conductivity of the Gd hydrides films changed along with those estimated from the Wiedemann–Franz Law and electrical conductivities.

Tailoring microstructure of superabsorbent film for active food packaging using carboxy methyl cellulose and biogenic vaterite CaCO3–Ag hybrid microspheres

Eliminating microbial growth and preventing food degradation from excess moisture is an important technological advance in packaging. This article describes the development of a novel antimicrobial superabsorbent pad for food packaging, which uses carboxy methyl cellulose (CMC) as a polymer matrix and biogenic vaterite calcium carbonate microspheres loaded with AgNPs (CaCO3–Ag). The spherical vaterite CaCO3–Ag hybrid was obtained by precipitating CaCO3 from discarded eggshells in silver colloid. The vaterite CaCO3–Ag microspheres were incorporated into the CMC matrix, which underwent physical cross-linking initially and was further chemically cross-linked during film surface treatment. The resulting three-layer film exhibits improved hardness and modulus of 0.09 and 3.30 GPa, respectively. The crystallinity was enhanced, and water absorption capacity attained was 13.87 times of film weight. The antimicrobial activity with inhibition zones of 6 and 14 mm against Escherichia coli and minced pork bacteria, makes it suitable for use as an antimicrobial superabsorbent pad in meat packaging applications.