Film Surface Research Articles

Corrosion behavior and mechanism of FeCoNi high-entropy alloy compared with X100 pipeline steel in a simulated alkaline soil environment

In this work, the corrosion behavior of FeCoNi HEA and X100 pipeline steel in a simulated Golmud soil environment was systematically studied utilizing electrochemical tests, surface analysis techniques and immersion measurement. The results indicate that FeCoNi HEA possesses superior anti-corrosion property than X100 steel by comparing the charge transfer resistance (Rct), passive current density (ip) and corrosion morphology. The microstructure and surface film are the principal factors causing the difference in corrosion resistance of the two alloys. More intact, uniform and dense passive film enhances the anti-corrosion performance of the HEA, while the nonprotective, loose and defective corrosion product film covering the surface of X100 steel is not conducive to inhibiting the corrosion of the steel substrate. The appearance of inclusions within the HEA can generate the micro-galvanic corrosion effect with the matrix, which promotes the substrate as an anode to induce pitting. Furthermore, multiple phases of X100 steel exhibits higher electrochemical activity compared to the HEA with a single Face Center Cubic (FCC) phase, which accelerates the corrosion of the steel. Moreover, the matrix of the HEA primarily experiences selected dissolution of Ni element.

Effect of micro-/nano-porous thin film surfaces prepared by a hybrid method of etching and electrochemical deposition on pool boiling heat transfer performance

Surfaces created using efficient and inexpensive methods are highly demanded in industrial applications of extremely high temperatures. In this study, Composite Nano-particle Coated Over CuO Filmed (CNCCF) surface is prepared through two processes, first through chemical etching to produce a thin film of CuO over bare Cu surface, and secondly deposition of Ni-Al2O3 composite nano-particle over CuO thin filmed copper surface by electrochemical deposition process. The completed CNCCF surface exhibits favorable characteristics for improved boiling heat transmission, such as wettability, roughness, porosity, etc. An experiment on pool boiling is conducted on the CNCCF and bare Cu surface. DI water at atmospheric pressure is used as the boiling fluid. Findings show that the CNCCF surface exhibits enhanced Critical Heat Flux (CHF) and Boiling heat Transfer Coefficient (BHTC) than bare Cu surface. The increased porosity, roughness, and other properties of the CNCCF surface are the cause of this improvement in CHF and BHTC. A high-speed camera is also used to monitor and analyze bubble behavior during boiling on all surfaces, including the Bare Cu. Further evidence for the enhancement of boiling heat transfer on the CNCCF surface comes from the nucleation site density, departure diameter, and frequency characteristics of bubbles.

Development of Ti Bipolar Plates with Micro-Structured Surface Film for Proton Exchange Membrane Fuel Cells

Development of Ti Bipolar Plates with Micro-Structured Surface Film for Proton Exchange Membrane Fuel Cells

Effects ofAs8structure formation on the surface morphology and internal microstructure of GaAs thin films.

Gallium arsenide (GaAs) materials have the advantages of high electron mobility, electron saturation drift rate, and other irreplaceable semiconducting properties. They play an important role in the electronics, solar and other fields. However, during GaAs film sedimentary growth, As atoms can undergo segregation to formAs8clusters because of the influence of external factors, which affect the surface morphology and internal structure of these films. In this study, a series of investigations on the deposition and growth of GaAs crystal films were performed. Additionally, the deposition and growth of GaAs thin films were simulated using molecular dynamics. The influence of As8clusters on the surface morphology and internal structure of GaAs films at different incidence angles, velocities and substrate temperatures was studied by using 'defect analysis technology' and 'diamond structure identification' in open source software, along with surface roughness and radial distribution function. Results show that with increasing incident angle, the number ofAs8clusters decreases and film density increases. Increasing incident velocity increases the irregular movement ofAs8clusters in air, and their deposition on the film surface affects the morphology of the film, and the surface roughness increases first and then decreases. Additionally, we investigated the effect of different substrate temperatures on the film surface. Results show that at a substrate temperature of 1173 K, the number ofAs8clusters in the film decreases or the As8clusters disappear, heterogeneous nucleation occurs in the film, and the crystallization rate increases. Although the dislocation line associated with nucleation may affect the mechanical and optical properties of the film, it considerably reduces the annealing effort after the deposition and growth.

Photothermal Welding Strategy for Mechanical Stability and High Efficiency of ETL‐Free f‐PSCs

AbstractFlexible perovskite solar cells (f‐PSCs) have drawn widespread interest owing to their distinguished advantages in excellent flexibility and relatively low cost. However, the brittle grain boundaries (GBs) and defects in flexible perovskite film tremendously influence the power conversion efficiency (PCE) and mechanical flexibility of f‐PSCs. Herein, photothermal welding, a novel method, is used to improve the perovskite films quality and the PCE of f‐PSCs with a near‐infrared (NIR) dye (indocyanine green, ICG) and polycaprolactone (PCL) as additives. Due to the strong photothermal effect, ICG molecule not only can significantly enhance NIR light harvesting, but it also can weld GBs upon exposure to an NIR laser, which is conducive to the GBs connections and device flexibility. Meanwhile, the S═O bond of ICG and C═O bond of PCL can simultaneously coordinate with Pb2+ defects in perovskite. Furthermore, they can control crystal growth to form a smooth surface of perovskite film. Consequently, the unencapsulated PSCs based on ICG/PCL displays a high champion PCE of 20.62%, with 88.4% of the original PCE after being placed in dark conditions for 600 h. The f‐PSCs delivers a champion PCE of 19.55% and exhibits excellent mechanical stability, thus providing a meaningful scientific direction to fabricate high‐flexible f‐PSCs.

High-Temperature (Cu,C)Ba2Ca3Cu4Oy Superconducting Films with Large Irreversible Fields Grown on SrLaAlO4 Substrates by Pulsed Laser Deposition

(Cu,C)Ba2Ca3Cu4Oy is a nontoxic cuprate superconducting material with a superconducting transition temperature of about 116 K. Recently, it was found that bulk samples of this material synthesized under high pressure hold the highest irreversibility line among all the superconductors, which is very promising for its application in the liquid nitrogen temperature field. In this work, high-temperature (Cu,C)Ba2Ca3Cu4Oy superconducting films with large irreversible fields were prepared on SrLaAlO4(00l) substrates by pulsed laser deposition. The substrate temperature during deposition proved to be the most important parameter determining the morphology and critical temperature of the superconductors, with 680 °C considered to be the optimum temperature. X-ray diffraction (XRD) results showed that the (Cu,C)Ba2Ca3Cu4Oy films prepared under optimal conditions exhibited epitaxial growth with the a-axis perpendicular to the film surface and the b- and c-axes parallel to the substrate, with no evidence of any other orientation. In addition, resistivity measurements showed that the onset transition temperature (Tconset) was approximately 116 K, the zero-resistance critical temperature (Tc0) was around 53 K, and the irreversible field (Hirr) was about 9 T at 37 K for (Cu,C)Ba2Ca3Cu4Oy films under optimal temperature. This is the first example of the successful growth of superconducting (Cu,C)Ba2Ca3Cu4Oy films on SrLaAlO4(00l) substrates. This will facilitate high-performance applications of (Cu,C)Ba2Ca3Cu4Oy superconducting materials in the liquid nitrogen temperature field.

Synthesis of CS-Fe3O4/GO nanocomposite for adsorption of heavy metal in aqueous environment.

In this study, magnetic material based on graphene oxide (GO) was developed for enhanced adsorption capacity for heavy metals. The Fe3O4 nanoparticles were combined with the GO material using a chitosan (CS) binder to obtain the CS-Fe3O4/GO nanocomposite. The adsorption capacity of this nanocomposite was evaluated by removing heavy metals including Ni2+ ions. When GO was composed with Fe3O4 and CS, the GO films were densely covered with ferromagnetic particles, which were bound and densely distributed on the GO film surface due to the interaction between GO and CS. The optimal conditions for the complexation of Ni2+ and 4-(2-pyridyl azo)-rezoxine (PAR) are 1 mL Ni2+, 2 mL PAR 100 mg/L, pH = 6 (adjusted with 0.7 mL of the 0.1 M K2HPO4 solution) and a complexation time of 20 min. After 50 min of adsorption, the Ni2+ removal efficiency of the CS-Fe3O4/GO nanocomposite reached 81.21 % and the corresponding adsorption capacity was 2.03 mg/g. The Ni2+ removal process followed the first-order model and Freundlich isotherm. This process was spontaneous (∆Go < 0) and an exothermic process (∆Ho = -1128.875 J.mol-1). In addition, the factors affecting this process were investigated, including the pH solution, the dosage of the CS-Fe3O4/GO nanocomposite and the initial Ni2+ concentration. The CS-Fe3O4/GO nanocomposite showed a potential adsorption capacity in removing Ni2+ at low concentrations from wastewater.

Constructing Multi‐Functional Polymeric‐Termination Surface Enables High‐Performance Flexible Perovskite LEDs

AbstractFlexible perovskite light‐emitting diodes (f‐PeLEDs) have attracted increasing interest to realize true‐color, low‐cost, and light‐weight wearable optoelectronic and flexible display applications. However, their external quantum efficiency (EQE) and mechanical stability lag far behind because of the inherent surface and brittle issues of polycrystalline perovskite films. In this work, a multi‐functional polymeric‐termination surface of perovskite film is constructed for achieving efficient and mechanically stable f‐PeLEDs. It takes the roles to not only reduce defects through equipping coordination groups to improve emission properties, but also optimize film morphology and eliminate pinholes to solve the long‐standing issue of leakage current. Meanwhile, the polymeric‐termination surface with anchoring points and polymeric soft chains on perovskites demonstrates synergetic effects beyond the corresponding functional group‐only or polymer‐only strategies in reducing the Young's modulus and improving the mechanical flexibility. Ultimately, the record EQE of 22.1% and significantly enhanced mechanical stability of maintaining 82% of the initial performance after 2000 bending cycles with radius of 5 mm are achieved in pure‐green f‐PeLEDs. The work paves the way for the development of high‐performance flexible optoelectronic devices.

Investigation of thermal effects in bulk oxide chemical mechanical polishing

Bulk oxide polishing occupies a substantial portion of time to achieve surface planarization in semiconductor manufacturing. Recently, thermal management has emerged as a critical issue in the polishing process. Fundamental research on thermal effects in oxide film polishing is essential for optimizing both the thermal management system and the polishing process itself. Experiments indicate that friction force, significantly influenced by wafer and retainer ring pressures as well as slurry species, plays a major role in determining polishing temperature, more so than slurry flow rate. An important finding is the temperature-dependent behavior of slurry particles, which generally reduce in size and concentrate more at higher temperatures, with aggregation starting at around 80 °C. High-temperature slurry deteriorated pad properties but enhance oxide film surface hydrolyzation. During a 60-s polishing process, the slurry temperature exhibited the maximum removal rate at 60 °C for fumed silica polishing, while for calcined ceria, the highest removal rate was observed at 20 °C. Pad B at ambient temperature, having similar hardness to Pad A at 60 °C, reduced the oxide film removal rate by 31.82 % for fumed silica and 40.94 % for calcined ceria. This indicates that pad hardness has a more pronounced effect on polishing with calcined ceria slurry.

A Comprehensive Study on Structural and Optical Properties of Zinc Selenide/Poly Ortho-methoxyaniline Hybrid Thin Films Deposited by Chemical Bath Deposition and Plasma Polymerization Techniques

Hybrid thin films hold dominant importance in various technological applications due to their synergistic effects between inorganic and organic materials. In this study, inorganic–organic hybrid thin film has been produced where the inorganic layer of zinc selenide (ZnSe) is deposited first through chemical bath deposition technique and the organic layer is deposited onto the inorganic layer using a capacitively coupled plasma polymerization technique. The ZnSe layer deposited for one hour has been used as the base layer and plasma polymerized (PP) o-methoxyaniline (OMA) has been deposited for different deposition durations. The experimental results showed that thickness of the the hybrid films increases with the organic layer deposition time. The field emission scanning electron microscope exhibited a large number of pores on the surface of the ZnSe film, which are significantly covered up when organic PPOMA is deposited onto it. The energy-dispersive X-ray confirms the constitutional elements of the hybrid films and X-ray diffraction study indicates the enhancement of crystallinity of the film. Differential scanning calorimetry and thermogravimetric analysis specify that hybrid films are thermally more stable (up to 396 °C) compared to pure ZnSe film (351 °C), probably due to higher conjugation in the PP organic layer. The direct optical band gaps of the deposited hybrid thin films are found to increase from 2.4 to 2.80 eV with the increase of organic layer onto ZnSe film. Consequently, the Urbach energy decreases from 0.94 to 0.66 eV with the deposition of hybrid film for different time durations. The outcomes of this study suggest that the hybrid films would have enormous potential as passive thin films for photovoltaic cells, sensing and optical devices.

Physiochemical and electrical activities of nano copper oxides synthesised via hydrothermal method utilising natural reduction agents for solar cell application

Abstract The aim of this study is to explore the potential compatibility of copper oxide nano-powders synthesised via hydrothermal method for solar cell applications by triggering a reaction between copper acetate and various reducing agents derived from natural resources, including Arabic gum, molasses, starch, and vinegar. X-ray diffraction analysis revealed the crystalline phases of the synthesised materials, indicating the successful synthesis of copper oxide material, which was confirmed by identifying patterns that matched specific copper oxide phases. Fourier transform infrared spectroscopy was employed to analyse the molecular vibrations and chemical compounds present in the reducing agents. The reducing properties of the selected materials and their capacity to convert copper acetate into copper oxide were validated. Field-emission microscopy and transmission electron microscopy analyses of the synthesised copper oxide nanoparticles (NPs) revealed variations in particle size and morphology. These variations were dependent on the particular reducing agent utilised during synthesis. Moreover, the carrier concentration, mobility, and resistivity were evaluated as the electrical properties of the spin-coated copper oxide thin films. Hall effect analysis determined that the choice of reducing agent significantly influenced the carrier concentration (n) and mobility (µ) of the films. Remarkably, nano copper oxide films synthesised using starch exhibited irregular spherical grains with porous surfaces. Starch-synthesised samples showed the highest conductivity of n = 1.2 × 1019 cm−3 when compared with those synthesised with other reducing agents. This suggests that the porous surfaces in the starch-synthesised films may have contributed to their enhanced conductivity compared to films synthesised with alternative reducing agents. In summary, the findings emphasised the influence of the reducing agent on the size, morphology, and electrical conductivity of the copper oxide NPs.

High-performance tin perovskite transistors through formate pseudohalide engineering

The lack of high-performance p-type semiconducting materials hinders the integration of complementary metal-oxide semiconductors with well-established n-type metal-oxide counterparts. Although tin halide perovskites are promising p-type material candidates, their practical implementation is hindered by excessive hole concentrations and difficulties in precisely controlling crystallization, which leads to poor device performance and yield. In this paper, we propose a formate pseudohalide engineering method to overcome these issues and demonstrate high-performance tin perovskite thin-film transistors (TFTs). The incorporation of formate anion greatly suppresses the vacancy defects at the surfaces of the perovskite films with an increase in crystallinity and grain size. This reduces the hole concentration and eliminates the dependence on the addition of excessive tin fluoride for hole suppression. Hence, high-performance TFTs with a high average field-effect hole mobility of 57.34 cm2 V−1 s−1 and on/off current ratios surpassing 108 can be achieved, approaching p-channel low-temperature polysilicon devices.

Surface-Enhanced Raman Spectroscopy Detection for Fenthion Pesticides Based on Gold Molecularly Imprinted Polymer Solid-State Substrates.

Current label-free surface-enhanced Raman spectroscopy (SERS) assay for the detection and analysis of organophosphorus pesticides has achieved initial success, but the application still faces constraints of substrate portability and specificity. To this end, this paper demonstrates a method for portable, rapid, and specific detection of low concentrations of fenthion pesticides based on a solid substrate of gold nanoparticle monolayers combined with molecularly imprinted polymers (MIPs). The nano-monolayers were transferred to the surface of mercapto-silicon wafers by interfacial self-assembly technique to form a stable connection with S-Au bonds and, at the same time, prevent nanoparticles from dropping off during the surfactant removal process. Then, the fenthion MIPs were directly generated on the surface of the monolayer film by spin-coating with a pre-polymerization solution and ultraviolet-induced polymerization. Tests showed that the molecular imprint was able to accurately bind to fenthion, but not other molecules, in a mixture of structural analogs, achieving a low concentration detection of 10-8 mol/L. The composite substrate maintained a signal uniformity of a relative standard deviation (RSD) = 7.05% and a batch-to-batch reproducibility of RSD = 10.40%, making it a potential pathway for the extended application of SERS technology.

Alterations in the tear film and ocular surface in pediatric migraine patients.

To evaluate the ocular surface (OS) parameters in the pediatric migraine patients (PMPs). This prospective case-control study consisted of 51 PMPs (PMP group) and 55 healthy pediatric patients (HPP group). In all participants, tear function was evaluated subjectively using the Ocular Surface Disease Index (OSDI) questionnaire, objectively using Schirmer tear test (STT) and tear film disintegration time (TBUT), and with clinical and laboratory examinations (conjunctival impression cytology). The PMP group was subdivided into two groups according to their aura. The mean age and gender distribution of the study groups were almost the same (P > 0.05 for both of them). In the PMP group, both the STT value and the TBUT value were significantly lower than those determined in the HPP group (P = 0.021 and P = 0.018, respectively). In the PMP group, the OSDI scores were higher than those in the HPP group (P = 0.032). In the PMP group, the goblet cell density values were lower than those in the HPP group (P = 0.01). With regard to the aura, the TBUT and STT values were nonsignificantly lower in the PMP aura-positive group than in the PMP aura-negative group (P > 0.05 for both of them). The OSDI assessment was similar in both the groups. With regard to the goblet cell count, it was observed to be less in the PMP aura-positive group than in the PMP aura-negative group (P = 0.01). Influence of OS in children with migraine was also demonstrated using the samples taken from the conjunctiva. These changes were also demonstrated by objective tests such as STT and TBUT. Both clinical objective evaluations and pathologic changes were more prominent in the migraine with aura group.

Structural properties controlled magnetisation of Ni/Al multilayers sputtered on flexible polymer substrate: Impact of Ni deposition rates

The goal of this work is to determine how the rate of Ni deposition rates affect the structural characteristics that regulate the magnetization of Ni/Al multilayer thin films sputtered on flexible acrylic acetate polymer substrates. The films with a 5[Ni(20 nm)/Al(10 nm)] structure were gradually sputtered as different Ni deposition rates in the total thickness of 150 nm. With an increase in the rate of Ni deposition, the Ni contents increased from 61.5% to 69.6%. And, X-ray diffraction analysis verified that the films featured a face-centered cubic structure with variable peak intensities. Also, the scanning electron microscopy surface morphology analyses revealed that variations in the film surfaces were a result of the deposition rates. For magnetic measurements, the differences in the structural analysis were observed to cause a notable variation in saturation magnetization, MS, and coercivity, HC values. Accordingly, MS values increased consistently between 359.0 and 389.7 emu cm−3, but HC values decreased from around 34–32 to 28 Oe with the increase in Ni deposition rate from 0.02 to 0.10 nm s−1. It is also observed that when the Ni layers are generated at very fast deposition rates, the Ni/Al multilayer films have a high MS/HC ratio, which is significant for magnetic sensors. It has been concluded that the magnetisation of Ni/Al multilayer thin films can be controlled by the structural properties adjusting the Ni deposition rate.

High-performance Ga2O3 solar-blind UV photodetectors via film growth regulation and surface state engineering

Gallium oxide (Ga2O3) with a wide bandgap is emerging as one of the most promising candidates for solar-blind photodetectors (SBPDs). However, the practical application of Ga2O3-based SBPDs is impeded by substantial defects-related leakage currents, sluggish response speed, and high-cost, making their practical applications face great challenges. Here, we proposed strategic films growth regulation and surface state engineering to grow high-quality yet economical β-Ga2O3 films, thereby achieving high-performance SBPDs. High-resolution transmission electron microscopy revealed the presence of high-quality films with an extremely regular arrangement of β-Ga2O3 (2‾01) planes. The full width at half maximum and root mean square roughness values are 0.07° and 0.716 nm, respectively. The β-Ga2O3 films demonstrated a significant reduction in VO concentrations after O2/N2 plasma treatment. This process can effectively minimize thermal damage to the sample surface while retaining highly reactive free radicals. The photocurrents of devices can be further enhanced, leading to a larger PDCRs of 8.6 × 107, through N2 plasma treatment. Moreover, the films effectually suppress the persistent photoconductivity effect with τr and τd values of 5.31/0.97 s and 0.49/0.87 s before and after N2 plasma treatment, respectively. We have demonstrated the influence mechanism of O2/N2 plasma treatment on photoelectronic performance. This study provides a practical approach to growing high-quality β-Ga2O3 films and preparing high-performance but low-cost Ga2O3-based SBPDs.

Effect of Drying Conditions and Jojoba Oil Incorporation on the Selected Physical Properties of Hydrogel Whey Protein-Based Edible Films.

Edible hydrogel coatings or films in comparison to conventional food packaging materials are characterized as thin layers obtained from biopolymers that can be applied or enveloped onto the surface of food products. The use of lipid-containing hydrogel packaging materials, primarily as edible protective coatings for food applications, is recognized for their excellent barrier capacity against water vapor during storage. With the high brittleness of waxes and the oxidation of different fats or oils, highly stable agents are desirable. Jojoba oil obtained from the jojoba shrub is an ester of long-chain fatty acids and monovalent, long-chain alcohols, which contains natural oxidants α, β, and δ tocopherols; therefore, it is resistant to oxidation and shows high thermal stability. The production of hydrogel films and coatings involves solvent evaporation, which may occur in ambient or controlled drying conditions. The study aimed to determine the effect of drying conditions (temperature from 20 to 70 °C and relative humidity from 30 to 70%) and jojoba oil addition at the concentrations of 0, 0.5, 1.0, 1.5, and 2.0% on the selected physical properties of hydrogel edible films based on whey protein isolate. Homogenization resulted in stable, film-forming emulsions with bimodal lipid droplet distribution and a particle size close to 3 and 45 µm. When higher drying temperatures were used, the drying time was much shorter (minimum 2 h for temperature of 70 °C and relative humidity of 30%) and a more compact structure, lower water content (12.00-13.68%), and better mechanical resistance (3.48-3.93 MPa) of hydrogel whey protein films were observed. The optimal conditions for drying hydrogel whey protein films are a temperature of 50 °C and an air humidity of 30% over 3 h. Increasing the content of jojoba oil caused noticeable color changes (total color difference increased from 2.00 to 2.43 at 20 °C and from 2.58 to 3.04 at 70 °C), improved mechanical elasticity (the highest at 60 °C from 48.4 to 101.1%), and reduced water vapor permeability (the highest at 70 °C from 9.00·10-10 to 6.35·10-10 g/m·s·Pa) of the analyzed films. The observations of scanning electron micrographs showed the heterogeneity of the film surface and irregular distribution of lipid droplets in the film matrix.

Realization of Atomically Uniform ALD-Al2O3 and TiO2 on SiO2 and GeO2 by UV-Ozone Treatment

Thermally oxidized SiO2/Si and GeO2/Ge are difficult to form very thin oxide films by atomic layer deposition (ALD) due to the chemical inertness of the oxide film surface. In this study, the effect of surface modification of insulating films by the UV-Ozone (UVO) method on ALD was investigated with the aim of controlling the atomic layer thickness and producing a uniform oxide film. The results show that UVO treatment can deposit atomic layer-thick films on SiO2 or GeO2 without delay. This may be due to the formation of dangling bonds on the oxide film surface, which improves the reactivity between the surface and the precursor during initial layer formation.

Study of Biocomposite Films Based on Cassava Starch and Microcrystalline Cellulose Derived from Cassava Pulp for Potential Medical Packaging Applications

This study aimed to develop biocomposite films based on cassava starch and microcrystalline cellulose (MCC) derived from cassava pulp for potential medical packaging applications. MCC was extracted from cassava pulp, and its structure and chemical composition, crystallinity, and thermal properties were characterized. The MCC showed a yield of 14.92% and crystallinity of 46.91%. Different MCC contents (1%, 3%, and 5% w/w of starch) were incorporated into cassava starch films. The effects of MCC contents on film properties, including morphology, thickness, mechanical strength, chemical interactions, moisture content, surface wettability, and water activity index, were studied. The effects of UV-C sterilization on the disinfection of starch/MCC on film properties were determined. Results showed that all starch/MCC films exhibited good transparency and thickness ranging from 127 to 144 µm. As MCC content increased from 1 to 5%, Young’s modulus and tensile strength of the films improved significantly from 112.12 to 488.89 MPa and 3.21 to 11.18 MPa, respectively, while elongation at break decreased from 44.74 to 4.15%. Incorporating MCC also reduced film surface wettability, with the water contact angle increasing from 69.17° to 102.82°. The starch/3%MCC holds promise as a biocomposite film for medical packaging applications, offering advantages in terms of good transparency, mechanical properties, and surface hydrophobicity. Furthermore, the absence of microbial growth in the sterilized gauze pad with sealing in the sterilized starch/3%MCC film confirms that the UV-C sterilization, 30 min for each side at 254 nm effectively eliminated any microorganisms present on the starch/3%MCC film without damaging the film properties. This finding highlights a reliable approach to ensuring the sterility of starch/MCC films for medical packaging applications.

Goos–Hänchen shift for coupled vibrational modes in a semiconductor structure

We present a theoretical investigation of the Goös–Hanchen shift (GHS) experienced by acoustic and optical vibrational modes reflected and transmitted from the surfaces of a semiconductor thin film sandwiched between two semi-infinite media. Our study focuses on the impact of the incident angle on the GHS, considering the coupling between longitudinal and transverse modes. For acoustic vibrations, our findings reveal that the GHS can reach magnitudes up to seven times larger than the thickness of the thin film and up to 20 times larger than the incident wavelength. Besides, it is shown that this significant amplification of the GHS highlights the strong influence of the incident angle and the frequency of the modes involved. In the case of optical vibrations, we observe even more pronounced GHS values, exceeding 30 times the incident wavelength. This demonstrates the potential of GHS in acoustical systems, which opens up possibilities for applications in the design of acoustic devices.