Pure Films Research Articles

High-Energy Density Pure Polyvinylidene Difluoride with the Magnetic Field Modulation of Free-Volume Pore Size and Other Microstructures.

PVDF polymer dielectrics, renowned for their ultra-high-power density, ultra-fast response times, remarkable toughness, and lightweight properties, constitute the essential material foundation for the development of dielectric capacitors. Nevertheless, the low-energy density of these dielectrics presents a challenge to the advancement of dielectric capacitors. In this paper, in the process of preparing monolayer pure PVDF dielectric films by the solution casting method, a fixed-direction magnetic field and a rotating magnetic field were introduced in the horizontal direction, respectively, and this investigation explores the impact of magnetic field modulation on the polymer films' free-volume pore size, grain size, phase structure, dielectric properties, and energy storage capabilities by altering the duration and orientation of the magnetic field's influence. This study also discusses how microscopic alterations, particularly in the free-volume pore size, affect the macroscopic dielectric properties. Polymer films treated with a magnetic field of constant orientation for 3 min were obtained with the smallest free-volume hole size of 2.91 Å, the highest γ-phase contents of 54.8%, the smallest grain size of 68 Å, the largest electrical displacement of 10.64 and a very high discharge energy density of 12.68 J/cm3 (a 200% enhancement over pure PVDF).

Physico-mechanical Properties of Nano Bio-films For Application in Food Packaging

Petroleum-based packaging has long dominated the packaging industry, raising environmental concerns. As a result, the packaging industry has started using nano bio-plastics. Incorporating nanoparticles, nano bio-plastic packaging helps in prolonging product shelf life. Additionally, packaging manufactured of nano bio-plastic is made of biodegradable polymers. Nano bio-films made from polylactic acid (PLA) and nanoclay were produced using a solvent casting process. 1.0%, 3.0% and 5.0% (wt.) of nanoclay were added to the PLA solution. The mechanical, chemical, morphological and transparency properties of nano bio-films were investigated. To improve their suitability for food packaging applications, tensile test, Fourier-transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM) and UV-barrier test were performed. With tensile strength (TS) of 30.36 MPa and elongation at break (EAB) of 7.05%, respectively, nano bio-films with 3.0 wt. % nanoclay demonstrated higher mechanical properties than pure PLA film with about 35% of increment. In aspects of FTIR analysis, no significant differences were found with both nano bio-films and pure PLA film. The SEM morphology shows that adding nanoclay at 3.0 wt. % improves the adhesion between the PLA matrix and the nanoclay. The addition of nanoclay had a minimal impact on the PLA film's transparency, and it was interesting to see that nanoclay concentration of 1.0 wt. % and 3.0 wt. % had roughly the same light transmission values of 84.86% and 83.95%, respectively. According to the findings of this study, the PLA nano bio-film with 3.0 wt% nanoclay exhibits the optimum physico-mechanical properties.

Investigate the Physical Properties and Transmitted sunlight of PVC/PMMA/ ZnO Nanocomposite Films

Pure blend (PVC0.3g +PMMA 0.2g) and blend/ZnO nanocomposite films with different amounts were created using the solution casting technique. Different amounts of zinc oxide from (0.001, 0.002, 0.003, 0.004, and 0.005)g were investigated and added to blend polymer with a fixed amount (0.5) g of PVC/PMMA in 15ml tetrahydrofuran (THF). The XRD results demonstrated the amorphous structure of the admixture film and the hexagonal crystal structure of ZnONPs. The ZnONPs in the film were also atomically dispersed resulting in the incorporation of the ZnONPs peaks within the polymer matrix. FESEM image of the mixture and ZnO revealing small white spots scattered on the surface of the mixture with some agglomerates. FTIR spectroscopy data showed no chemical interaction between the polymer blend and ZnONPs. The increasing amounts of ZnONPs improved the absorbance, absorption coefficient, and extinction coefficient of the blend polymer. The blended polymer's permeability and energy gap decreased from 4.48eV to 3.91eV with the increase in the number of ZnONPs in the nanocomposites. The transmitted sunlight intensity was measured through the blended pure polymer films and the blended nanocomposites/ZnO nanocomposites. At the beginning of September 2021, the intensity of transmitted sunlight was measured in Baghdad for a period of 7 days. As can be observed, almost all films have the same ratio of the intensity of transmitted radiation to the intensity of sunlight for all hours and days.

Photo-responsive Cu-tannic acid nanoparticle-mediated antibacterial film for efficient preservation of strawberries

The existing films used for fruit preservation suffer from insufficient preservation abilities. This study introduces Cu-tannic acid (Cu-TA) nanoparticles, synthesized from tannic acid (TA) and Cu2+, to enhance food packaging properties. Integrated into a chitosan-gelatin (CG) matrix, the resultant Cu-TA nanocomposite films exhibit superior antibacterial efficacy and killing rates of Escherichia coli and Staphylococcus aureus more than 99 %, and double the shelf life of strawberries, underscoring the exceptional freshness preservation capabilities of film. Additionally, the tensile strength of the Cu-TA nanocomposite films increased by 1.75 times, the DPPH radical scavenging percentage increased from 29.4 % to 68.4 %, and the water vapor permeability (WVP) decreased by about 60 % compared to the pure CG films. Comprehensive cytotoxicity and migration assessments confirm the safety of film, paving the way for their application in food packaging. The excellent performance of the Cu-TA nanocomposite films positions them as a formidable solution for protecting perishable food items.

ALd of Metal Fluorides–Potential Applications and Current State

AbstractMetal fluoride thin films are important materials in a multitude of applications. Currently, they are mostly used in optics, but their potential in energy harvesting and storage is recognized as well. Atomic layer deposition (ALD) is an advanced thin film deposition method that has an ever‐increasing role in microelectronics. The assets of ALD are its capability to produce uniform, stoichiometric, and pure films with precise thickness control even on top of complicated structures, such as high aspect ratio trenches. These characteristics can be beneficial in applications of metal fluoride thin films but so far ALD of metal fluorides has remained much less studied and used than ALD of metal oxides, nitrides, sulfides, and pure metals. This review aims to motivate research on ALD of metal fluorides by surveying potential applications for ALD metal fluoride thin films and coatings. The basics of luminescent applications, antireflection coatings, and lithium‐ion batteries will be discussed. Next, the fundamentals of ALD will be presented followed by a comprehensive summary of the metal fluoride ALD processes published so far.

Organic Dye Molecule Intercalated Prussian Blue for Simultaneously Enhancing Coloration Efficiency and Energy Storage Capacity in Electrochromic Battery.

The dual-functional device combining electrochromic properties and energy storage has gained numerous attentions in the field of energy-saving smart electronics. However, achieving simultaneous optimization of coloration efficiency and energy storage capacity of materials poses a significant challenge. This study presents a novel approach by incorporating methyl orange into Prussian blue channels (PB-MO films) to adjust the internal electronic structure of Prussian blue. This modification allows the active layer to simultaneously improve the electrochromic and energy storage performance. The introduction of methyl orange not only alters the ratio of Fe3+/Fe2+ within the framework through the coordination reaction of Fe3+ with methyl orange, but also improves the reaction kinetics after intercalating organic dye molecules, including charge transfer resistance, diffusion capability of ions and capacitive contribution. The PB-MO films demonstrate remarkable properties: high optical contrast (81.4% at 670nm), excellent coloration efficiency (265 cm2C-1), and significant specific capacity (84 mAh m-2 at 0.05 A m-2), outperforming pure PB films. The PB-MO films are ideally suited for applications in displays and intelligent energy storage fields, boasting both high coloration efficiency and substantial energy storage capacity, thus advancing promote the development of dual-functional electrochromic devices.

Sol-Gel Derived Alumina Particles for the Reinforcement of Copper Films on Brass Substrates.

The aim of this study is to provide tailored alumina particles suitable for reinforcing the metal matrix film. The sol-gel method was chosen to prepare particles of submicron size and to control crystal structure by calcination. In this study, copper-based metal matrix composite (MMC) films are developed on brass substrates with different electrodeposition times and alumina concentrations. Scanning electron microscopy (FE-SEM) with energy-dispersive spectroscopy (EDS), TEM, and X-ray diffraction (XRD) were used to characterize the reinforcing phase. The MMC Cu-Al2O3 films were synthesized electrochemically using the co-electrodeposition method. Microstructural and topographical analyses of pure (alumina-free) Cu films and the Cu films with incorporated Al2O3 particles were performed using FE-SEM/EDS and AFM, respectively. Hardness and adhesion resistance were investigated using the Vickers microindentation test and evaluated by applying the Chen-Gao (C-G) mathematical model. The sessile drop method was used for measuring contact angles for water. The microhardness and adhesion of the MMC Cu-Al2O3 films are improved when Al2O3 is added. The concentration of alumina particles in the electrolyte correlates with an increase in absolute film hardness in the way that 1.0 wt.% of alumina in electrolytes results in a 9.96% increase compared to the pure copper film, and the improvement is maximal in the film obtained from electrolytes containing 3.0 wt.% alumina giving the film 2.128 GPa, a 134% hardness value of that of the pure copper film. The surface roughness of the MMC film increased from 2.8 to 6.9 times compared to the Cu film without particles. The decrease in the water contact angle of Cu films with incorporated alumina particles relative to the pure Cu films was from 84.94° to 58.78°.

Sensitivity-enhanced plasmonic sensor modified with ZIF-8

ZIF-8 is a typical metal–organic framework (MOF) material, which has great potential for sensor improvement. In this paper, we prepared a high sensitivity surface plasmon resonance (SPR) sensor based on ZIF-8/Au and described the preparation process of the sensor and characterized the samples in detail. The results showed that the synthesized ZIF-8 nanoparticles were uniform with an average diameter of about 50 nm. The performance of the sensor was related to the amount of ZIF-8, which could be controlled by adjusting the number of spin-coating cycles. When the refractive index ranged from 1.3335 to 1.3635, the maximum sensitivity of the sensor reached 3961.36nm/RIU with one cycle of spin-coating, which was 74.05% higher than that of pure Au single-layer film sensor. Furthermore, the feasibility of the proposed sensor for biological sensing was demonstrated by detecting bovine serum albumin (BSA).

Structural and Optical Properties of SnS2:Cu Thin films prepared by chemical Spbay Pyrolysis

Thin filis have been prepared from the tin disulphide (SnS2 ), the pure and the doped with copper (SnS2:Cu) with a percentages (1,2,3,4)% by using ahemical spray pyrolysis techniqee on substrate of glass heated up to(603K)and sith thicknesses (0.7±0.02)?m ,after that the films were treated thermally with a low pressure (10-3mb) and at a temperature of (473K) for one hour. The influence of both doping with copper and the thermal treatment on some of the physical characteristics of the prepared films(structural and optical) was studied. The X-ray analysis showed that the prepared films were polycrystalline Hexagonal type. The optical study that included the absorptance and transmitance spectra in the weavelength range (300-900)nm demonstrated that the value of absorption coefficient (?) was greater than (104 cm-1) for the pure and doped films and that the electronic transitions at the fundamental absorption edge were of the indirect kind whether allowed or forbidden and the value of the optical energy gap in the case of the indirect transition, the allowed decreased from (2 eV) to (1.8,1.7,1.5,1.2)eV at the doping percentages (1,2,3,4)% respectively, also it was found that the value of energy gap for the pure and doped films increased after annealing. Tthe absorption and transmission spectra were used to find the optical constant including refractive index(n), extinction coefficient (k), imaginary and real part of dielectric constant (?1 &?2) , and it was found that all the optical constant was affected by changing the doping percentages; in addition to being affected after treating the films thermally

Effect of different metallic doping elements on the physical properties of iron oxide thin films

This study investigates the physical properties of pure and Co, Cr, Mn, and Ni-doped Fe2O3 thin films fabricated using spray pyrolysis techniques on glass substrates. The primary aim is to understand how doping influences the structural, optical, and dielectric properties of Fe2O3 thin films. The deposition parameters were kept constant for all samples, with a fixed dopant concentration of 3 weight percent (wt%). X-ray diffraction (XRD) analysis revealed a single diffraction peak indexed as (104), decreasing in crystallite size from 17.27 nm for the pure film to approximately 11.5 nm for all doped films. Field emission scanning electron microscopy (FE-SEM) images displayed non-homogeneous grain formation, characterized by an average grain size larger than the crystallite size, indicating agglomeration. The optical band gap value shifted from 2.54 eV for the pure film to higher values upon doping with various elements, signifying direct allowed transitions. Changes in refractive index dispersion with wavelength were observed based on the dopant type. The application of the Spitzer-Fan model revealed an increase in high-frequency dielectric constant upon doping compared to the pure film, varying across different dopants. Photoluminescence (PL) spectra recorded under excitation at 340 nm exhibited multiple emission peaks within the spectral range of 399 to 600 nm.

Hydrogel Films with Impact Resistance by Sacrificial Micelle-Assisted-Alignment.

Various strategies are developed to engineer aligned hierarchical architectures in polymer hydrogels for enhanced mechanical performance. However, chain alignment remains impeded by the presence of hydrogen bonds between adjacent chains. Herein, a facile sacrificial micelle-assisted-alignment strategy is proposed, leading to well-aligned, strong and tough pure chitosan hydrogels. The sacrificial sodium dodecyl sulfate micelles electrostatically interact with the protonated chitosan chains, enabling chain sliding and alignment under uniaxial forces. Subsequently, sacrificial micelles can be easily removed via NaOH treatment, causing the reforming of H-bond in the chain networks. The strength of the pure chitosan hydrogels increases 140-fold, reaching 58.9±3.4MPa; the modulus increases 595-fold, reaching 226.4±42.8MPa. After drying-rehydration, the strength and modulus further rise to 70.3±2.4 and 403.5±76.3MPa, marking a significant advancement in high-strength pure chitosan hydrogel films. Furthermore, the designed multiscale architectures involving enhanced crystallinity, well-aligned fibers, strong interfaces, robust multilayer Bouligand assembly contribute to the exact replica of lobster underbelly with impact resistance up to 6.8±1.0kJ m-1. This work presents a promising strategy for strong, tough, stiff and impact-resistant polymer hydrogels via well-aligned hierarchical design.

Unlocking superior preservation: The synergy of lignin and zeolite in chitosan-based composite films for perishable foods

Chitosan-based films are confronted with several technical challenges that impede their broad application in the preservation of perishable foods, such as suboptimal mechanical properties and insufficient antioxidant activity. In this work, we have introduced lignin (LG) and natural clinoptilolite zeolite (NCZ) into pure chitosan-based films to address the above limitations. The synergistic incorporation of LG and NCZ has endowed the composite films, designated as CTSLC, with a suite of enhanced attributes, including improved thermostability, enhanced UV-shielding capability and hydrophobicity, augmented antioxidant activity, refined gas selectivity, and bolstered mechanical properties. The enhancements in the antioxidant activity, gas selectivity, and mechanical properties of CTSLC are notably pronounced, reflecting a substantial advancement in their overall performance. These attributes surpass those of both pure chitosan-based film or commercial polyethylene film. Consequently, CTSLC could keep the freshness and appearance of strawberries and mangoes at least 60 hours and 10 days, respectively. The findings suggest that CTSLC has the potential to be a promising material for the preservation of perishable foods, offering a significant advancement in the field of food packaging and preservation technology.

Mechanical Properties, Microstructure, Degradation Behavior, and Biocompatibility of Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg Guided Bone Regeneration Barrier Membranes Prepared Using a Powder Metallurgy Method.

Pure zinc exhibits low mechanical properties, making it unsuitable for use in guided bone regeneration (GBR) membranes. The present study focused on the preparation of Zn alloy GBR films using powder metallurgy, resulting in Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR films. The tensile strength of the pure Zn GBR film measured 85.9 MPa, while an elongation at break was 13.5%. In contrast, Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR films demonstrated significantly higher tensile strengths of 145.3 and 164.4 MPa, respectively, whereas elongations at break were 30.2% and 19.3%. The addition of Ti, Fe, and Mg substantially enhanced the mechanical properties of the zinc alloys. Corrosion analysis revealed that Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes exhibited corrosion potentials of -1.298 and -1.316 V, respectively, with corresponding corrosion current densities of 12.11 and 13.32 μA/cm2. These values were translated to corrosion rates of 0.181 and 0.199 mm/year, indicating faster corrosion rates compared to pure Zn GBR membranes, which displayed a corrosion rate of 0.108 mm/year. Notably, both Zn-based alloy GBR membranes demonstrated excellent cytocompatibility, with a cytotoxicity rating of 0-1 in 25% leachate. Additionally, these membranes exhibited favorable osteogenic ability, as evidenced by the quantitative bone volume/tissue volume ratios (BV/TV) of new bone formation, which reached 30.3 ± 1.4% and 65.5 ± 1.8% for the Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes, respectively, after 12 weeks of implantation. These results highlighted the significant potential for facilitating new bone growth. The proposed Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes showed promise as viable biodegradable materials for future clinical studies.

Effect of C additives with 0.5 % in weight on structural, optical and superconducting properties of Ta–Nb–Hf–Zr–Ti high entropy alloy films

We investigated the superconducting (SC) properties of Ta–Nb–Hf–Zr–Ti high-entropy alloy (HEA) thin films with 0.5 % weight C additives. The C additives stabilize the structural properties and enhance the SC critical properties, including μ0Hc2 (13.45 T) and Tc (7.5 K). The reflectance of the C-added HEA film is enhanced in the low-energy region, resulting in a higher optical conductivity, which is consistent with the lower electrical resistivity. In addition, we observed SC vortices in the C-added HEA film using magnetic force microscopy. The magnetic penetration depths (λ) of the pure HEA and C-added HEA films were estimated from their Meissner force curves by comparing them with those of a reference Nb film. At 4.2 K, the λ of the C-added film is 360 nm, shorter than that of the pure HEA film (560 nm), indicating stronger superconductivity against an applied magnetic field.

Antibacterial performance of biodegradable polymer and hazelnut husk flour antibacterial biofilm with silver nanoparticles

The antibacterial performance of biocomposite films prepared from lignocellulosic waste (hazelnut husk or hazelnut leafy green cover) modified with silver nanoparticles and polylactic acid (PLA) was determined. The amount of hazelnut husk in the PLA matrix ranged from 10 to 40% by weight in 10% increments. The composite pellets were produced using a twin-screw extruder. Biocomposite films of 0.6 mm x 40 mm x 200 mm were produced from the pellets in a laboratory hydraulic hot press. The surfaces of the modified hazelnut husk and biocomposite specimens were analyzed by scanning electron microscopy (SEM) and inductively coupled plasma optical emission spectrometry (ICP-OES). The antibacterial activity of the biocomposite films against Staphylococcus aureus bacteria was determined using the ASTM E 2149 (2020) method. The antibacterial activity of the biocomposite films increased noticeably with the addition of hazelnut husk modified with the silver nanoparticles. Compared to the pure PLA film, the biocomposite films with 10 wt% modified husk flour showed the lowest antibacterial activity (31.3%) against S. aureus over 24-h while the films with 40 wt% showed the highest antibacterial activity (99.9%). The biocomposite films made of hazelnut husk flour with silver nanoparticles and PLA matrix could be considered for food packaging applications.

Bicontinuous nickel/tin oxide films with enhanced photoelectrochemical hydrogen production efficiency

Self-assembled bicontinuous NiO:SnO2 films are proposed for enhanced photoelectrochemical hydrogen production efficiency due to their high interface-to-volume ratio and three-dimensional interconnectivity. The X-ray diffraction confirms the superior crystallinity of the bicontinuous NiO:SnO2 films. Bicontinuous NiO:SnO2 films reveal a heterostructure of mixed NiO and SnO2 phases, where the NiO phase exhibits the distribution of small grains, whereas the SnO2 phase exhibits large agglomerates of SnO2 crystals embedded in the NiO structure. The bicontinuous NiO:SnO2 films exhibit lower bandgap energy and higher electrical conductivity compared to pure NiO and pure SnO2 films. The photoresponsivity of the bicontinuous oxide films is higher than pure NiO and pure SnO2 films. These results imply the presence of strong charge interactions at the three-dimensional interfaces in bicontinuous NiO:SnO2 films. The hydrogen revolution reaction analysis confirms that the bicontinuous NiO:SnO2 films exhibit higher photoelectrocatalyst hydrogen production activity compared to pure NiO and pure SnO2 films.

Boosting photoelectrochemical water splitting performance via nanostructured Ag-CuO thin films

Undoped and doped copper oxide (CuO) with silver (Ag) was prepared using the SILAR technique on the ITO substrate to generate green hydrogen from the water-splitting process. The (−111) and (111) were the most intense reflections of crystallographic planes observed in pure and Ag-doped CuO thin films. Ag doping within the crystal structure of pristine leads to increasing the crystallite size. FESEM images show homogeneity and uniform distribution for the pure and Ag-doped CuO thin films that confirm the particles have small sizes, give more features and are responsible for the target application. The doping process affected the energy band gap where it was 2.2 eV for the pure sample then descended to 1.9 eV as doping reached 5 % concentration of Ag element. The photoelectrochemical testing showed that the Ag 5 % content photoelectrode has a high value of photocurrent density approximately ∼ - 5 mA/cm2.

Double-crosslinked polyvinyl alcohol/starch bioplastic with superior water-resistance and flame retardancy

The high water solubility and flammability of polyvinyl alcohol (PVA) limits its further widespread use in areas such as bioplastic and green packaging. In this study, double-crosslinked polyvinyl alcohol/starch bioplastics (named PDA) were fabricated using PVA, dialdehyde starch (DAS), and phytic acid (PA), resulting in a material with superior water resistance, flame retardancy, and excellent degradability. PA not only plays the role of catalyst for the chemical crosslinking but also as the physical crosslinker to form the intermolecular hydrogen bonds with PVA and DAS. This chemically and physically double cross-linked network structure results in PDA bioplastics with excellent toughness and water resistance. Specifically, the optimal formulation with 15 % PA content, designated as PDA15, exhibited a high toughness of 35.5 MJ/m3 and demonstrated prolonged shape retention in the boiling water. Additionally, PA also serves as a flame-retardant and antibacterial agent; the PDA15 achieved a high limit oxygen index (LOI) value of 40.0 % and passed the UL-94 V-0 rating without melt dripping, along with better degradability compared to pure PVA film. These outstanding performances make the PDA bioplastics highly promising for various applications, particularly in disposable plastics and laminated flexible packaging materials.

Experimental and theoretical studies of sputter deposited pure SnO2 thin films for high selective and humidity-tolerant H2 gas sensor

Experimental and theoretical studies of sputter deposited pure SnO2 thin films for high selective and humidity-tolerant H2 gas sensor

Design and in vitro/in vivo evaluation of chitosan-polyvinyl alcohol copolymer material cross-linked by dynamic borate ester covalent for pregabalin film-forming delivery system

This research introduced a novel polymer synthesized by combining chitosan and modified polyvinyl alcohol, cross-linked with boric acid using dynamic covalent bonds. The polymer was developed to formulate a pregabalin Film-forming system (FFS) for treating postherpetic neuralgia via topical application, showcasing notable skin adhesion and drug delivery properites. The chitosan-boric acid-modified polyvinyl alcohol polymer was analyzed using NMR, FTIR. The exceptional features of the optimized FFS were evaluated through rheometer, Differential scanning calorimetry (Tg = 45.98 °C), contact angle (θ = 78.62°). The elongation (60.05 ± 3.67 %), cohesion (56.94 ± 4.65 MPa) and skin adhesion (58.12 ± 2.99 kPa) of chitosan-boric acid-modified polyvinyl alcohol were found to be 5.2, 6.8, and 8.3 times higher than those of the pure chitosan film, attributed to the double network structure formed by the cross-linked reversible dynamic covalent bond. The optimized pregabalin FFS exhibited increased in vitro (86.25 ± 1.87 μg/g) and in vivo (100.42 ± 7.44 μg/g) skin retention amounts compared to in vivo oral administration (28.43 ± 4.61 μg/g). In summary, the utilization of borate ester dynamic covalent bonds in developing chitosan-based film-forming polymer proved beneficial in improving skin adhesion and topical therapeutic effectiveness, thereby mitigating the risk of systemic side effects associated with oral administration.