Properties Of Multilayer Films Research Articles

From multilayer LDPE/EVOH flexible film scraps to new multilayer films

This study explores the mechanical and optical properties of multilayer films incorporating recycled materials, mimicking the structure of industrial films. Using a coextrusion blown film line with a three-layer ABC configuration extrusion head, films were produced using two different recycled multilayer films, from post-industrial scraps, in layers A and B and virgin low-density polyethylene (LDPE) in one of the external layers (C). These recycles result from multilayer films mainly constituted of LDPE; one has also linear-LDPE (LLDPE) Metallocene, and the other has Ethylene Vinyl Alcohol (EVOH). Both recycled materials enabled to maintain blown film extrusion process stability during film production. The multilayer films produced with the incorporation of recycles were characterized using scanning electron microscopy (SEM), haze and gloss measurements, and tensile tests. Films with Recycled EVOH presented haze values much higher than those obtained for the Recycled Metallocene. However, all films presented good mechanical properties when compared to single layer virgin LDPE film. Anisotropic behaviour was observed, emphasizing the directional dependence of mechanical properties. The findings provide insights into the behaviour of multilayer films with recycled content, offering valuable information for the development of sustainable packaging solutions.

Effect of Cu addition on the optical, electrical, and structural properties of ultrathin Ag-based oxide/metal/oxide multilayer films

Ga and Al co-doped ZnO (GAZO) were used as oxide layers to fabricate GAZO/Ag/GAZO sandwich multilayer transparent conductive films. The effects of Cu addition in the middle layer on the optical, electrical, and structural properties of multilayer films were investigated. The influences of the Ag-Cu layer and GAZO layer thickness on the optical and electrical properties of multilayer films were further studied. The experimental results show that co-sputtering Cu and adding an ultrathin Cu seed layer changed the growth pattern of Ag films. GAZO/Ag-Cu/GAZO and GAZO/Cu/Ag/GAZO multilayer films exhibit high optical transparency and high electric conductivity. The annealing treatment can enhance the optical and electrical properties of the GAZO/Ag-Cu/GAZO and GAZO/Cu/Ag/GAZO multilayer films. The lowest sheet resistance of 9.49 Ω sq−1 and maximum average light transmittance in the visible range of 95.74 % can be obtained for the GAZO/Ag-Cu/GAZO films. The corresponding figure of merit is 68.18×10−3 Ω−1. The addition of Cu in the GAZO/Ag/GAZO multilayer films led to high transmittance and low resistivity, which can be used in various photoelectronic fields to replace indium tin oxide films.

Comparison of properties of multilayer film sputtered on glass and polypropylene substrates with angular DC magnetron Co-sputtering system

Complex multilayer film structures were fabricated through a custom-built angular DC magnetron co-sputtering system. In this system, separate Cu, Al, and brass (Cu + Zn) targets were mounted on three magnetron guns, working in conjunction with a rotating substrate. This study aimed to compare the properties of films with intricate structures, which were sputtered onto glass slides and polypropylene substrates. The sputtering process was optimized using a Box–Behnken design, considering three variable operating conditions: substrate rotation speed, sputtering time, and sputtering voltage. The Analysis of Variance (ANOVA) results for film thickness and roughness, sputtered with three different materials onto glass slides and polypropylene (PP) substrates, indicated that all three independent variables significantly influenced the optimum response, with P-values less than 0.05 (<α = 0.05). The optimal conditions for maximizing the thickness and roughness of the sputtered film on PP substrates differed from those obtained for the thin-film properties of the sputtered film on glass slide substrates. Top-view images of the surface morphology revealed a dense and granular structure for the film deposited on the glass slide, whereas some grooves between the grains and fractures were observed in the film on the PP substrate.Additionally, it was evident that these sputtered multilayer films exhibited a complex structure, as reflected in the uniform and homogeneous distribution of Cu, Al, and Zn atoms on both glass slides and PP substrates.

THE INFLUENCE OF STRUCTURAL AND COMPOSITIONAL FACTORS ON THE REALIZATION OF THE EXCHANGE BIAS EFFECT IN (Cr-Mn)/Fe20Ni80

The influence of a number of physical factors on the structural and hysteresis properties of multilayer films (Cr-Mn)/Fe Ni has been studied. By indirect signs, the presence of antiferromagnetism in Cr-Mn layers with a Mn content in the range of 20-40 at.% has been established. It is shown that in such structures, the exchange bias effect can be observed, but only when the thickness of the antiferromagnetic layer is greater than 40 nm. The initial reason for the low "fixing" properties of the Cr-Mn layer is its weak magnetic anisotropy, which is superimposed with instability in the reproduction of the micro-structure. The use of substrate heating during film deposition increased the reproducibility of microstructure parameters and hysteresis characteristics but led to a weakening of the exchange bias effect, apparently due to changes in the structure and composition of the interlayer interface.

Automated, High-Throughput Screening of Hybrid Elastin-like Polypeptide/Polysaccharide Multilayer Film Deposition.

The self-assembled layer-by-layer technique has attracted a great deal of attention as a method for engineering bio-functional surfaces under mild chemical conditions. The production of multilayer films, starting from newly designed building blocks, may be laborious, considering the inherent limitations for anticipating how minimal changes in the macromolecular composition may impact both film deposition and performance. This paper presents an automated, high-throughput approach to depositing polyelectrolyte multilayers (PEMs) in multiwell plates, enabling the screening of nearly 100 film formulations in the same process. This high-throughput layer-by-layer (HT-LbL) method runs in an affordable, fully commercial platform using Python-coded routines that can be easily adapted for the materials science lab settings. The HT-LbL system was validated by investigating the deposition of polysaccharide-based films in multiwell plates, probing the absorbance signal of ionically stained polyelectrolyte multilayers (PEMs) prepared in one single batch. The HT-LbL method was also used to investigate the deposition of PEMs with a small library of genetically engineered elastin-like polypeptides (ELPs) with different levels of ionizable and hydrophobic amino acid residues. The deposition of ELP/chitosan films was assessed based on the signal of fluorescently labeled species (chitosan or ELP-mCherry), demonstrating that both electrostatic and hydrophobic residues are essential for film buildup. The growth and surface properties of ELP-mCherry/chitosan films also seemed susceptible to the assembly pH, forming a higher film growth and a rougher and more hydrophobic surface for both polyelectrolytes deposited under a low ionization degree. Overall, this study illustrates the challenge of predicting the growth and properties of multilayer films and how the HT-LbL can accelerate the development of multilayer films that demand high levels of testing and optimization.

Novel multilayer chitosan/emulsion-loaded syringic acid grafted apple pectin film with sustained control release for active food packaging

The clove essential oil (EO) emulsions were prepared using syringic acid grafted apple pectin (SAAP) and soy protein isolate (SPI). This emulsion was used to improve properties of pullulan film (inner layer), which can be used for active packaging. Furthermore, chitosan was employed as the outer layer of the multilayer film prepared to address the limitations of existing pullulan films. Mechanical, optical, and functional properties of multilayer films were determined. The emulsions produced by SAAP display better emulsifying properties, smaller and uniform droplet size distribution. In comparison with AP-SPI-Pul, water vapor and oxygen permeabilities of SAAP-SPI-Pul were lower, while antioxidant, antimicrobial properties and barrier properties to UV were improved. Chitosan film can be used as the outer layer to modify the hydrophilicity/hydrophobicity of films with water contact angle of 98.4°. SAAP-SPI-Pul-Chit film has characteristics of high-performance films with favorable optical and mechanical properties. Furthermore, antioxidant and antimicrobial properties, as well as fruit preservation properties of the SAAP-SPI-Pul-Chit films were strengthened, which is attributed to the sustained release of clove EO in films.

Friction and Wear Properties of Multilayer Films Designed on Tantalum Substrate

In this paper, a titanium nitride film (TiN) monolayer film was deposited on a pure Tantalum (Ta) substrate with Ti as an intermediate layer by magnetron sputtering technique, and a Ta/Ti/DLC (diamond-like carbon)/Ti/TiN/DLC multilayer film was designed. Raman spectroscopy and scanning electron microscopy were used to observe the film structure and morphology. Friction and wear properties of Ta/Ti/TiN monolayer film and Ta/Ti/DLC/Ti/TiN/DLC multilayer film were analyzed by UMT-3 tester. The results show that the surface of multilayer film is denser and better bonded than TiN monolayer film. Under dry friction conditions, the friction coefficient of TiN monolayer film is stable at about 0.45. In contrast, the friction coefficient of DLC multilayer film remains around 0.15 with very small fluctuation during the whole friction process. This is determined by the inherent characteristics of DLC film, which is composed of sp2-C graphite structure and sp3-C diamond structure. From the analysis of the wear mechanism, the Ta substrate mainly undergoes adhesive wear and abrasive wear, however, the TiN monolayer film and Ta/Ti/DLC/Ti/TiN/DLC multilayer films mainly undergo abrasive wear mechanism. The friction coefficient of TiN monolayer fluctuates more than that of dry friction conditions in the body-liquid environment, and finally stabilize at about 0.5. The friction coefficient of DLC multilayer films does not differ much from those of dry friction conditions. This is because the TiN monolayer film generates a large amount of abrasive chips to fill the scratches in the body fluid environment, accompanied by the peeling and flaking of the compacted abrasive chips, thus the friction coefficient fluctuates greatly. The DLC multilayer films also undergoes graphitization transfer. In addition, the free hanging bonds of DLC film are passivated, which reduces the degree of adhesive wear. In summary, the DLC multilayer film has better biocompatibility, wear resistance, and stronger bonding.

Dimensionless analysis of the elastoplastic constitutive properties of single/multilayered films under nanoindentation

<p indent="0mm">Among the features of substrate-film structures, based on the load-displacement curves obtained from the nanoindentation tests, the intrinsic parameters of film material (elastic modulus, hardening exponent, and yield strength) are considered as the influential parameters in the load-displacement curves in terms of the applied load and work done in the loading phase. Based on the influential parameters combined in a dimensionless manner, the dimensionless function formulations are presented in association with the finite element simulation results, leading to a novel methodology proposed to solve the constitutive parameters appropriate for single-layered elastoplastic film materials. The advantage of the proposed dimensionless function in reproducing the finite element prediction results is verified by comparing it with the constitutive parameters predicted by machine learning algorithms based on the vast indentation data. In addition, by proposing the concept of “composite constitutive parameters”, the constitutive parameters of unknown single-layered films are established using a layer-by-layer strategy based on finite element simulations, followed by the subsequent determination of the constitutive parameters of multilayered films. The current work on the mechanical properties of multilayered films holds significant potential in improving the reliability and lifetime of the systems and devices based on thin film technology.

Emerging materials and technologies of multi-layer film for food packaging application: A review

Food packaging is an essential component of the development in food industry, as it is capable of protecting food from physical, chemical and biological contamination. Synthetic plastic packaging is by far the most commonly used for packaging; however, it leads to considerable environmental problems. The use of biodegradable plastics derived from natural polymers can address this issue. Nevertheless, natural polymers have poor barrier properties. This review aims to provide an overview of the various polymers used in multi-layer packaging and also to explain their physical, mechanical and barrier properties in detail. Hence, the application of a multi-layer film that combines the unique features of different polymers may produce packaging materials with improved performance, such as mechanical and barrier properties. The properties of multi-layer films with different types of polymers (biomass, synthesis-derived and microbial-derived) are thoroughly discussed. The results show that the multi-layer films possessed superior properties as compared to single-layer films in term of physical, mechanical and gas barrier properties. Suggestions for future research on the compatibility of multi-layer film in packaging applications are also addressed in this review. This paper offers an overview of the development of biodegradable natural polymer multi-layer films for packaging applications in the food industry.

Structure and Properties of Multi-Layer Films of High-Entropy Metals Deposited by the Ion-Plasma Method

Structure and Properties of Multi-Layer Films of High-Entropy Metals Deposited by the Ion-Plasma Method

Multilayer gelatin/myofibrillar films containing clove essential oil: Properties, protein-phenolic interactions, and migration of active compounds

Multilayer active films from gelatin and myofibrillar protein were developed (Gel-Sur film), and a film incorporated with clove (Eugenia spp.) essential oil (EO) was prepared by the casting-laminated method. Mechanical, optical, and structural properties of multilayer films were characterized. Moreover, the release of phenols into different food simulants and antioxidant properties were analyzed. The lamination process effectively improved the barrier properties and increased transparency value. Meanwhile, the elongation at break of multilayer film was declined with the increasing EO concentration. Fourier transform infrared (FTIR) analysis revealed the alteration of amide bonds, and protein-phenolic interactions were observed in the protein secondary structure. The multilayer film showed good antioxidant activity, and the active compounds showed the fastest release in water and the greatest antioxidant efficiency in 50% ethanol. Thus, the multilayer active film is a promising material in alcoholic foods.

Recent Studies on the Fabrication of Multilayer Films by Magnetron Sputtering and Their Irradiation Behaviors

Multilayer films with high-density layer interfaces have been studied widely because of the unique mechanical and functional properties. Magnetron sputtering is widely chosen to fabricate multilayer films because of the convenience in controlling the microstructure. Essentially, the properties of multilayer films are decided by the microstructure, which could be adjusted by manipulating the deposition parameters, such as deposition temperature, rate, bias, and target–substrate distance, during the sputter process. In this review, the influences of the deposition parameters on the microstructure evolution of the multilayer films have been summarized. Additionally, the impacts of individual layer thickness on the microstructure evolution as well as the irradiation behavior of various multilayer films have been discussed.

Influence of point defects on phase transformation and optical properties of TiO2 thin films via multilayering deposition technique

Thin anatase TiO2 films with preferential (004) orientation were successfully fabricated via multilayering technique, growth and stop repeatedly, using DC-magnetron sputtering and annealed at a relatively low temperature. The multilayering deposition technique suppressed the number of oxygen vacancy defects in TiO2 films without interrupting the columnar growth. The main columnar structure oriented along (101) plane and along (004) plane. Confirmed by the texture coefficient, the preferential (004) orientation of TiO2 films increased with increasing number of compact layers and the highest value was observed for post-annealed films at 200 °C. The surface morphology analysis indicated that the increase of surface roughness with increasing number of compact layers was related to the promotion of crystallization. The optical properties of multilayer films revealed that high number of compact layers greatly enhanced their absorption in the entire visible region, expanded energy band gap and increased refractive index.

Anticoagulant Activity of Cellulose Nanocrystals from Isora Plant Fibers Assembled on Cellulose and SiO2 Substrates via a Layer-by-Layer Approach.

In this study, we report the isolation of cellulose nanocrystals (CNCs) from Isora plant fibers by sulfuric acid hydrolysis and their assembly on hydrophilic cellulose and silicon-di-oxide (SiO2) surfaces via a layer-by-layer (LBL) deposition method. The isolated CNCs were monodispersed and exhibited a length of 200–300 nm and a diameter of 10–20 nm, a negative zetapotential (−34–39 mV) over a wide pH range, and high stability in water at various concentrations. The multi-layered structure, adsorbed mass, conformational changes, and anticoagulant activity of sequentially deposited anionic (sulfated) CNCs and cationic polyethyleneimine (PEI) on the surfaces of cellulose and SiO2 by LBL deposition were investigated using a quartz crystal microbalance technique. The organization and surface features (i.e., morphology, thickness, wettability) of CNCs adsorbed on the surfaces of PEI deposited at different ionic strengths (50–300 mM) of sodium chloride were analysed in detail by profilometry layer-thickness, atomic force microscopy and contact angle measurements. Compared to cellulose (control sample), the total coagulation time and plasma deposition were increased and decreased, respectively, for multilayers of PEI/CNCs. This study should provide new possibilities to fabricate and tailor the physicochemical properties of multilayer films from polysaccharide-based nanocrystals for various biomedical applications.

Effects of lamellar organization and arabinoxylan substitution rate on the properties of films simulating wheat grain aleurone cell wall

Herein, we evaluated the properties of alternate arabinoxylan (AX)/(1→3) (1→4)-β-D-glucan (BG) multilayer films. AX was extracted from wheat at three growth stages and single-component and alternate overlapping multilayer films were prepared. The physical properties, water diffusion rate, and water mobility of multilayer films during water absorption and desorption were studied. There were significant differences in the AX content and arabinose-to-xylose ratio at different growth stages. The LAX/BG multilayer films showed excellent thermal stability and mechanical properties with an increase in the relative humidity. The AX multilayer films with a low substitution rate showed a better water-binding capacity, whereas water molecules in films with a high substitution rate showed higher mobility. Therefore, a low substitution rate AX and AX/BG composite structure can improve the thermodynamic properties of multilayer films, but limit water mobility. We provide new insights on the physicochemical properties and water-regulation effects of wheat cell wall.

Electrical insulating MXene/PDMS/BN composite with enhanced thermal conductivity for electromagnetic shielding application

Insulating materials with effective electromagnetic interference (EMI) shielding and heat dissipation are urgently required for modern electronic devices and systems, but it seems that the EMI shielding cannot be compensated without sacrificing the electrical insulation performance. In this study, a layer-by-layer spin coating process has been proposed to prepare multilayer films (MXene/polydimethylsiloxane/boron nitride, MXene/PDMS/BN) with ordered alternate structures, and the EMI shielding effectiveness (EMI SE), thermal conductivity, along with electrical insulation properties of multilayer films have been systematically investigated. The conductive network of MXene/PDMS layer was in-plane constructed, leading to the effective EMI shielding of the multilayer films. Moreover, the BN/PDMS layer can insulate the conductive path through plane and provides effective heat dissipation for multilayer films. The EMI SE of multilayer films is positively related to the number of layers, but the increase in the number of layers will deteriorate the thermal conductivity and electrical insulation performance. The EMI SE of the multilayer film with 11-Layers structure can reach 35.2 dB at 10.9 GHz, with a thermal conductivity of 0.65 W/m·K, and volume resistivity of 2.9 × 1012 Ω cm, as well as a breakdown strength of 3.29 KV/mm, respectively. This research can shed new light on the development of multifunctional composite, which can be envisioned as an advanced electronic packaging material.

High photoelectric performance of Cu-based AZO multilayer films deposited via TiO2 barrier layer and oxygen-containing atmosphere

Cu-based Al: ZnO (AZO) multilayer films with different barrier layers (Al and TiO2) were deposited on glass substrates under different deposition atmospheres (oxygen and no oxygen) by magnetron sputtering. The effects of Al layer, TiO2 layer and oxygen gas on structural, morphological, optical and electrical properties of the multilayer films were investigated. The AZO/Cu/TiO2/AZO multilayer film deposited in oxygen-containing atmosphere possesses a resistivity as low as 5.12 × 10−5 Ω cm, a sheet resistance of 7.31 Ω/sq., and an average visible optical transmittance of about 81%. It has the optimum photoelectric performance among all the reported multilayer or single-layer transparent conductive thin films, being confirmed by the highest figure of merit (FOM) of 15.59 × 10−3 Ω−1. These results indicate that the insertion of the TiO2 barrier layer and the filling of oxygen during the deposition of the top AZO layer is an effective method for improving the optical and electrical properties of the Cu-based AZO multilayer film.

Dynamic Self-Assembly of Polyelectrolyte Composite Nanomaterial Film.

The aim of this study is not only to investigate the feasibility of using PAH (polyallylamine hydrochloride) and PSS (poly styrene-4-sulfonic acid sodium salt) to prepare a film via a layer by layer self-assembly process entrained with silver nanoparticles, but also to show that the silver nanoparticles crystalline structure can be defined and deposited on the surface of the substrate in the desired alignment structure and manner, which is of great help to research on the LBL method in the cellulose field. The effect of outermost layer variation, assembly layers, and composition of multilayers on the formation of the LBL structure on a nanofibrillated cellulose (NFC)/polyvinyl alcohol (PVA) substrate was investigated. The deposition of PAH and PSS was monitored by Fourier-transform infrared spectroscopy (FT-IR). The morphology of the LBL film layers was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). Furthermore, thermal degradation properties were investigated by thermogravimetric analysis (TGA), and physical properties of multilayer films were tested by a universal mechanical tester. The results reveal that PAH and PSS can be readily deposited on a NFC/PVA substrate by using LBL methodology to prepare self-assembled polyelectrolyte multilayer films. The surface morphology of the LBL composite changed from negative to positive charged depending on the final LBL treatment. Also, according to SEM and AFM analysis, silver nanoparticles were well dispersed in the (PAH/PSS) film, which significantly improved the thermal stability of the composite films.

Cover Feature: Steady‐State and Time‐Resolved Optical Properties of Multilayer Film of Titanium Dioxide Sandwiched by Gold Nanoparticles and Gold Thin Film (ChemNanoMat 8/2019)

Cover Feature: Steady‐State and Time‐Resolved Optical Properties of Multilayer Film of Titanium Dioxide Sandwiched by Gold Nanoparticles and Gold Thin Film (ChemNanoMat 8/2019)

Elevated and cryogenic temperature micropillar compression of magnesium–niobium multilayer films

The mechanical properties of multilayer films consisting of alternating layers of magnesium and niobium are investigated through micropillar compression experiments across a broad range of temperatures. The data collected from the variable temperature micropillar compression tests and strain rate jump tests are used to gain insight into the operative deformation mechanisms within the material. At higher temperatures, diffusion-based deformation mechanisms are shown to determine the plastic behavior of the multilayers. Diffusion occurs more readily along the magnesium–niobium interface than within the bulk, acting as pathway for magnesium diffusion. When individual layer thicknesses are sufficiently small, diffusion can remain the dominant deformation mechanism down to room temperature. Multilayer strengthening models historically rely solely on dislocation-based arguments; therefore, consideration of diffusion-based deformation in nanolaminates with low melting temperature components offers improved understanding of multilayer behavior.