Properties Of Films Research Articles

Improved Dielectric and Energy Storage Properties of Polypropylene-Based Organic Films through Construction of a Microcompatible “Sea–Island” Structure

Improved Dielectric and Energy Storage Properties of Polypropylene-Based Organic Films through Construction of a Microcompatible “Sea–Island” Structure

Enhanced Thermoelectric Performance in Flexible Sulfur-Alloyed Ag2Se Thin Films.

Flexible thermoelectric generators can directly convert thermal energy harvested from the human body into electricity. The Ag2Se flexible film, a promising material for wearable thermoelectric generators, normally demonstrates an inferior electrical transport property due to its weakened in-plane mobility. In this study, the in-plane electrical transport properties of flexible Ag2Se films were optimized by alloying with additional sulfur. This optimization is achieved by leveraging the differences in elemental electronegativity and the preferred orientation of the Ag2Se films. The sulfur-alloyed Ag2Se thin film, with a nominal ratio of 3 atom %, can reach a maximum mobility of 1150 cm-2 V-1 s-1 at 300 K. So, the optimized room-temperature power factor increases to 1935 μW m-1 K-2. Furthermore, the Ag2Se film alloyed with 3 atom % sulfur exhibits excellent flexibility even after 1000 bending cycles with a radius of 5 mm, characterized by a relative resistance increment of less than 3%. In addition, the corresponding π-type flexible thermoelectric generator possesses a maximum power density of 51 W m-2 at a temperature difference of 50 K.

Characterization of the Physical, Mechanical, and Morphological Properties of Films Generated from Cassava Pomace

The pollution of the environment caused by conventional packing materials such as plastic has driven the need for biodegradable alternatives. Although starch is an important component in the development of such materials, starch is not suited for use as a biodegradable packaging material due to global hunger challenges. The current study successfully utilized the major industrial waste of the cassava starch processing industry to develop biodegradable films. Three packaging materials were developed using the casting procedure, which involved combining various quantities of cassava pomace (CP) and plasticizer combinations. The developed films were analyzed to evaluate their characteristics, such as color, thickness, density, moisture content, solubility, swelling index, mechanical properties, microscopic, and FT-IR characteristics. In contrast, concerning multiple aspects, each of the films demonstrated unique characteristics. The film with the lowest CP (C1) appeared to be thinner and lighter in color; however, it tended to contain a greater amount of moisture. The C1 film exhibited an adhesive property that was wellsuited for use as cling film. The intermediate CP film (C2) stands out because of its excellent mechanical characteristics, including high tensile strength and elongation at break. These attributes make it particularly well-suited for packaging applications, such as the production of biodegradable bags. Conversely, the swelling index and thickness of the highest CP film (C3) outperform both other films, suggesting that it may have the capacity to absorb higher moisture content. The scanning electron microscopic images revealed a uniform surface for all three samples. However, the cross-sectional images of C3 indicated internal cracks that were consistent with the lowest mechanical characteristics and flexibility. Therefore, the C3 film is more suitable for packaging items like plates. These films can serve as a viable, environmentally friendly, and biodegradable alternative to conventional packaging materials. Keywords: Mechanical properties, cassava pomace, physical properties, biodegradable films, micro-structure properties

Effects of inserted ultrathin Pt buffer on perpendicular magnetic properties of Ta/TbFeCo/Ta layered structures

We investigated effects of inserted ultrathin Pt buffer on the perpendicular magnetic properties of Ta/TbFeCo/Ta layered structures. For Tb-rich TbFeCo films buffered with Ta and Ta/Pt a compensation thickness is observed at ∼ 6 nm, where the net saturation magnetization vanishes. The perpendicular magnetic anisotropy properties of two structures are found to be governed by a competition of a perpendicular bulk anisotropy and an in-plane interface anisotropy. Compared with Ta-buffered TbFeCo films, the counterparts with insertion of Pt buffer exhibits a larger negative interface anisotropy. A large variation of saturation magnetization and perpendicular magnetic anisotropy with increasing inserted thickness of Pt buffer is observed in the Ta/Pt/TbFeCo/Ta structure. This can be ascribed to the interface-driven variation of exchange interaction between Tb and FeCo at the interface, confirmed by thermomagnetic measurements. A clear correlation between the interface-driven variation of exchange interaction and perpendicular magnetic properties of the TbFeCo films is identified. Our results show the interface plays an important role in the perpendicular magnetic properties of TbFeCo films, which is critical for the application in spintronic devices.

Tailoring epsilon-near-zero wavelength and nonlinear absorption properties of CdO thin films by Mo doping

Cadmium oxide (CdO) has recently attracted attention as a material with controllable properties tailored for optoelectronic and nanophotonic devices due to its superior mobility. However, its potential application in near-infrared (NIR) remains to be explored. In this work, we demonstrate that the epsilon-near-zero (ENZ) wavelength and nonlinear optical properties of CdO films can be effectively tuned by Mo doping. The results show that Mo doping increases the electron concentration as well as improve the crystalline quality of CdO. With increasing Mo doping, we achieve blueshifts of the ENZ wavelength from 2.89 to 1.56 μm. The nonlinear absorption (NLA) behavior at 1550 nm changes from reverse saturable absorption to saturable absorption with increasing Mo content. Moreover, significant improvement in NLA performance with nonlinear absorption coefficient β = −72 cm/GW is observed at the highest doping content. Our work shows that doped CdO films with tunable optoelectrical and nonlinear optical properties can be an ideal candidate for optoelectronic and nanophotonic application in the NIR region.

Synthesis, characterization, and antifungal properties of chrome-doped hydroxyapatite thin films

The development of thin films of chromium-doped hydroxyapatite (20CrHAp) deposited on silicon substrate by the spin coating method was realized for the first time. A coherent investigation of the physicochemical properties of 20CrHAp thin films was also carried out for the first time. The obtained thin films were studied by various techniques such as, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) investigations and fractal analysis. By scanning electron microscopy (SEM) studies were obtained valuable information about the surface morphology of the 20CrHAp thin films. The zeta potential (ZP), Dynamic light scattering (DLS) and ultrasound measurements (US) were used in order to evaluate the stability of 20CrHAp suspension. The ratio between the hydrodynamic diameter obtained by DLS and the particle diameter obtained by SEM was 1.6. The SEM results on 20CrHAp thin films suggested that the sample possess a conglomerate of nanoparticles unevenly distributed on their surface. The surface morphology of the 20CrHAp thin films was studied with the aid of atomic force microscopy (AFM). The AFM topography of the 20CrHAp thin film's surface highlighted that the thin films present the morphology of a continuum deposited layer composed of non-uniform particle conglomerates. The presence of hydroxyapatite on the surface of silicium substrate was revealed by the results of Fourier transform infrared spectroscopy (FTIR) investigations. The antifungal evaluation of the 20CrHAp thin films was performed using Candida albicans 10,231 ATCC fungal strain. The antifungal assays results depicted that the 20CrHAp thin films inhibited the fungal biofilm formation. More than that, the results of the antifungal studies revealed that 20CrHAp thin films exhibited good inhibitory effects on the development of the fungal cells on their surface. Furthermore, our investigation delves into the realm of Minkowski Functionals and fractal/multifractal analysis as applied to the examined films. Our findings reveal that nanocomposite coatings containing 20CrHAp exhibit robust antifungal characteristics, suggesting their viability as a compelling solution for advancing antifungal devices in biomedical contexts.

Optoelectronic properties of perovskite thin films derived from lead sulfide via radio frequency magnetron sputtering: effect of the substrate temperature

Methylammonium lead iodide (CH3NH3PbI3; MAPbI3) films were fabricated from sputtered lead sulfide (PbS) films prepared at various substrate temperatures according to the Thornton structural zone model. PbS films were converted to lead iodide (PbI2) and finally to MAPbI3 in a two-step gas-phase reaction. The increase in substrate temperature caused the morphology to change to fibrous interconnected grains, which played an important role in improving the optoelectrical properties of perovskite films. Moreover, enhanced charge transport of MAPbI3 films was observed owing to the fibrous interconnected PbI2 precursor, which was confirmed by a higher absorption coefficient and longer carrier lifetime.

Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressings

A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method. Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPO-oxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness), functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 μm, iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ± 0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03 to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films could be effectively utilized as antibacterial wound dressings.

Investigation of silicon nitride for spacer via plasma-enhanced atomic layer deposition using a (tert-butylamino)dimethylsilane precursor

Silicon nitride (SiNx) has attracted considerable attention as a spacer in advanced semiconductor devices, owing to its superior barrier performance. However, the fabrication of SiNx films remains challenging, because of the corrosive byproducts generated when using chlorine precursors and impurities associated with the redeposition species of precursor ligands. The selection of precursor and optimization of the process parameters influence the film growth and improve the film properties. In this study, the (tert-butylamino)dimethylsilane (TBADMS) precursor and N2 plasma were introduced for the first time by plasma-enhanced atomic layer deposition (PEALD) to deposit SiNx films. We attempted to improve the film properties by adjusting the substrate temperature and investigated different growth mechanisms. The film deposited at 300 °C exhibited the most superior film properties, with an N/Si ratio close to ideal Si3N4, high film density, smooth surface, and low wet etch rate. The proposed growth mechanism demonstrates the influence of the initial surfaces and residual redeposition species removal within the film. Additionally, dielectric characterization indicates that films deposited at a higher temperature exhibit enhanced dielectric constant and reduced hysteresis (k = 7.2, ΔV = 0.6 V) in comparison to those (k = 4.9, ΔV = 1.2 V) deposited at lower temperature.

Effect of recycled polypropylene on migration of six processing aids in polypropylene film to milk

Mechanically recycled plastics used in food packaging are consistent with the current circular economy concept. In this study, the effects of recycled polypropylene (rPP) content on film properties and the migration of processing aids in the film to food simulant and milk were studied by self-made rPP films. The results showed that the rPP and processing aids increased the transparency of the films. However, the presence of tiny particles in the rPP film reduced its elongation at break. Furthermore, rPP and processing aids decreased the thermal stability of the film. At 70 °C for 2 h, the total migration order of the processing aids to food simulant and milk was 50 % ethanol (55.78–64.17 mg/kg) > whole milk (10.32–10.66 mg/kg) > low-fat milk (6.39–7.04 mg/kg) > skim milk (4.88–5.47 mg/kg). The migration of processing aids into milk in films containing 50 % and 100 % rPP was similar to that of virgin polypropylene (vPP) films, which indicates that rPP does not promote processing aid migration. Moreover the overall migration order of processing aids to 2 % (w/v) food ingredient aqueous solution was lecithin (3.05 mg/kg) > glyceryl trilaurate (2.68 mg/kg) > cholesterol (1.33 mg/kg) > NaCl (0.33 mg/kg) > casein (0.32 mg/kg) > lactose (0.29 mg/kg) > water (0.16 mg/kg). This confirmed that milk fat was the primary cause of processing aids migration from the film, and the kind of milk fat also had an effect on processing aids migration. Therefore, as long as the basic performance and food safety of packaging are met, a certain proportion of rPP can be added to vPP to achieve sustainable development of packaging.

Dynamics of sphere impact on a suspended film with glycerol and surfactant

Understanding the dynamics and inherent mechanisms of sphere impact on suspended films is important for improving sphere-film separation techniques. In this study, we conducted experiments to investigate the dynamics of sphere impact on suspended films and examine typical phenomena. We revealed the effects of dynamic viscosity and surface tension of films by altering the glycerol content (G) and the relative surfactant concentration (C*) and elucidated the characteristics of film deformation, sphere trajectory (hs), and contact time (tc). Moreover, we obtained the influences of sphere and film properties on bubble volume (Vbub) by analyzing force balance. The results indicate that three modes are observed and divided using the dimensionless energy parameter E* = Ek0/(ΔEfs + Evis) based on energy analysis, considering the sphere kinetic energy (Ek0), film surface energy increment (ΔEfs), and viscous dissipation (Evis): satisfying E* < 1, retention occurs; satisfying 1 < E* < 127.7(Ds/Df)2 (where Ds is the sphere diameter, Df is the film diameter), bubble entrainment passing appears; satisfying E* > 127.7(Ds/Df)2, non-bubble entrainment passing emerges. During retention, increasing G and C* causes film surface elasticity and hs to present a trend of first rising and then falling. For passing, the increase in G reduces deformability, leading hs to decrease, while increasing C* makes the film more susceptible to deformation, causing hs to increase. In addition, a film vibration period (τf) is introduced to measure tc, satisfying tc > 2τf for retention, while satisfying tc < τf/3 for passing. Inspection of the relationship between film deformation and falling height indicates that Vbub enlarges with increasing Ds and C* but shrinks with increasing G and release height Hs0.

A pH-sensitive film based on chitosan/gelatin and anthocyanin from Zingiber striolatum Diels for monitoring fish freshness

As a new type of packaging method, the anthocyanin-based pH-sensitive indicator film has gained much attention owing to low cost, small size, and visually informative property. In this study, an intelligent film based on chitosan/gelatin (CG) matrix with Zingiber striolatum Diels (ZSD) anthocyanin for fish freshness monitoring was developed. The film properties, including thickness, moisture content, color, mechanical properties, UV–vis light barrier property, as well as pH and ammonia sensitivity, were evaluated. The CG-ZSD films exhibited a more compact structure when compared with the CG film. The CG-ZSD20 film showed the highest elongation at break (6.33 ± 0.62%) and lowest tensile strength (20.0 ± 0.58 MPa). FTIR spectra revealed the strong hydrogen bond interactions between ZSD and polymer matrix. Film incorporated with 15% anthocyanin extract has increased melting temperature at 118.9 °C, and a lower weight loss (13.8%) at melting temperature. In pH 1–14 buffer, the color of CG-ZSD films underwent a significant change from red to yellow-green. The CG-ZSD15 film was utilized for monitoring fish freshness and showed visible color changes from deep purple to brown. The total volatile basic nitrogen content and pH value changes of fish were closely related to the visual color changes in film. This demonstrated that the film was a highly pH-sensitive film for quantifying fish freshness in real-time.

Preparation and properties of biomass castor oil polyurethane films

In order to investigate the optimal conditions for the formation of castor oil-based polyurethane (CO-PU) films and their comprehensive performance, a series of experiments were carried out utilising biomass castor oil (CO) as the main reactant, 4,4-diphenylmethane diisocyanate (MDI) as the other main reactant, benzoyl peroxide (BPO) as the radical initiator, and dibutyltin dilaurate (DBTDL) as the catalyst. The CO-PUs with different R-values (the number ratio of –NCO/–OH substances) were prepared by pre-polymerisation under single-variable control. The effects of different R-values, DBTDL contents and curing temperatures on the mechanical properties and film-forming state of the CO-PUs were then investigated. Finally, the liquid-resistant medium properties and thermo-gravimetric analyses of CO-PU films were investigated. The experimental results demonstrate that when the R value is 2.5, the DBTDL content is 0.1 ‰, and the curing temperature of the film-forming process is 80 ℃, the tensile strength and elongation at break of the CO-PU film are 36.4 MPa and 49.05 % respectively, and the hardness of the pencil at this time is 6H. The water absorption rate is 0.01 %, and the contact angle of water is up to 83.5°. CO-PU displays a commendable resistance to sulfuric acid, sodium hydroxide, and ethyl acetate. Additionally, CO-PU exhibits a high thermal decomposition temperature. The comprehensive performance of CO-PU can be enhanced by modifying the film-forming conditions of CO-PU, which paves the way for further expansion of the applications of CO-PU in the future.

Effect of plasticizers on the rheological properties of xanthan gum - starch biodegradable films

The effect of plasticizers, namely glycerol, sorbitol, and citric acid, on the structural and mechanical properties of biodegradable films obtained from xanthan gum (XG) and starch was studied. The plasticizing effect of glycerol, sorbitol, and citric acid on XG-starch films is justified by the destruction of intermolecular contacts between starch and XG macromolecules and the redistribution of hydrogen bonds in the system as a result of the hydrotropic action of plasticizer molecules. The use of glycerol proved to be the most effective for regulating the deformation of films, while the use of sorbitol to preserve strength. The dependence of the film roughness on the type and concentration of plasticizers was characterized. The smallest values of protrusions on the surface of XG-starch films were found in the presence of sorbitol. Considering the effect of the concentration of plasticizers on the stickiness of the surface of XG-starch films and their structural and mechanical properties, 1.5 % concentration of glycerol, sorbitol and citric acid was determined as optimal.

Novel nanoemulsion-loaded hydroxyl propyl methyl cellulose films as bioactive food packaging materials containing Satureja khuzestanica essential oil

This study was conducted in response to a gap in the production of hydroxyl propyl methyl cellulose (HPMC) edible films from Satureja khuzestanica essential oil (SKEO) and to survey the preservation effect of natural edible films on the vapor phase. For these purpose varying concentrations of SKEO ranging from 1.25 % (EF1) to 7.5 % (EF5) led to producing different edible films for potential food packaging applications and the physicochemical, mechanical, and antimicrobial properties of edible films were evaluated across solid, liquid, and vapor phases. The incorporation of nanoemulsions into the polymer films led to an increase in thickness and opacity, while the addition of SKEO resulted in reduced water solubility without impacting film density. Notably, the antibacterial efficacy of the films was most pronounced against S. aureus, with a zone of inhibition measuring 41 ± 1 mm for EF5 on solid media. Time killing assays further demonstrated that specific formulations (EF3, EF4, and EF5) were capable of eradicating all microorganisms within 60 min. Moreover, SKEO edible films exhibited significant inhibitory effects against E. coli under refrigeration conditions (4 °C). These results highlighted the effect of herbal edible films in enhancing the functionality of bioactive food packaging technologies.

The outcomes of Zn doping on the properties of CuO thin films prepared via modified SILAR method and its impact on the performance of CuO-based solar cells using Cd0.4Zn0.6S-ETL and Spiro-OMeTAD-HTL

The outcomes of Zn doping on the properties of CuO thin films prepared via modified SILAR method and its impact on the performance of CuO-based solar cells using Cd0.4Zn0.6S-ETL and Spiro-OMeTAD-HTL

Synthesis, Characterization, and Antifungal Properties of Chrome-Doped Hydroxyapatite Thin Films

Synthesis, Characterization, and Antifungal Properties of Chrome-Doped Hydroxyapatite Thin Films

Conductive NR/PMMA-RAFT-CNT-rGO composites and their morphological, mechanical, and electrical properties

This study reports the synthesis of poly(methyl methacrylate) (PMMA)-carbon nanotube (CNT)-reduced graphene oxide (rGO) emulsions via reversible addition-fragmentation chain-transfer (RAFT)-mediated surfactant-free emulsion polymerization using a hydrophilic chain transfer agent. The rGO was prepared by the modified Hummers method and reduced with L-ascorbic acid. The effects of the CNT:rGO ratios and CNT and rGO contents on the conversion and stability of emulsion were investigated. Increasing the CNT and rGO contents from 1 to 4 wt% decreased the monomer conversion, while all the samples remained as colloidal dispersions. The morphology of PMMA-CNT-rGO composites showed the incorporated arrangement of a linear CNT portion connected with the rGO sheet dependent on the CNT:rGO ratio. Various PMMA-CNT-rGO filled natural rubber (NR) cast films were prepared. The NR/PMMA-CNT-rGO composite film with a 1 wt% filler loading at a CNT:rGO ratio of 1:1 presented a quite high modulus value (3.08 MPa) and sufficient intrinsic electrical conductivity (1.36 S/m) due to its strong filler-matrix interaction. Thus, the PMMA-RAFT-CNT-rGO composites at a very low filler content can be used as an effective reinforcement to enhance the mechanical and electrical properties of NR films with a high compatibility between the fillers and NR matrix.

Identifying orientation-dependent optical properties of single-crystalline β-Ga2O3 films

We explore the effect of crystallographic anisotropy on the optical properties of high-quality β-Ga2O3 thin films by conducting experimental measurements and theoretical simulations. High resolution x-ray diffraction measurements confirm the high-quality and the single crystalline quality, ruling out the effect of defects for all films. Raman spectra reveal the presence of anisotropy, as evident from a stronger Bg(2) mode related to GaIO4 chain libration in (100) orientation. Conversely, a stronger Ag(10) mode corresponding to tetrahedral bonds is evident in the (010) orientation, while it is suppressed in the (100) orientation. Low-temperature photoluminescence spectra indicate the presence of intrinsic impurity-related emissions in the ultraviolet and blue regions for all films. An anisotropic bandgap is observed, wherein the lowest bandgap value is related to the (010) oriented sample. Spectroscopic ellipsometry measurements confirm different refractive indices and extinction coefficient values depending on crystallographic orientation, which are in good agreement with the theoretical values obtained by density functional theory, confirming the anisotropic characteristics. The theoretical calculations of charge density show that the strength of covalent bonding depends on the β-Ga2O3 orientation, while experimental findings demonstrate that as the covalent bonding character increases, the film bandgap and the refractive index decrease. The anisotropy of β-Ga2O3 with respect to the crystal orientation leads to variations in the extinction coefficient, refractive index, and bandgap energy.

Sol-gel-derived WO3 thin films with structure-dependent NO2 sensing properties

The structure of metal oxide thin films can greatly affect their gas sensing properties. However, the structure-property relationship has not been fully established for the NO2 sensing properties of WO3 thin films. In this study, WO3 thin films with two distinct structures have been prepared by the sol-gel technique via employing two different precursor sols. Dense and porous WO3 thin films were successfully prepared as tungsten and WCl6 was used as the precursor source, respectively. Both WO3 thin films are exclusively sensitive to NO2 as low as 80 ppb. Porous WO3 thin films exhibit higher response toward NO2 but slower response/recovery kinetics as compared to the dense ones. Hall measurement and electrochromic coloration confirm the higher carrier mobility in the porous WO3 thin films. The response/recovery kinetics is found to be determined by the gas-solid reaction (receptor function), which is combinedly influenced by the porosity and grain size of the WO3 thin films.