Homogeneous Films Research Articles

Optimization of parameters for the preparation of AlN powder/thin films by tris(N,N,N’,N’-tetramethylethylenediamine) al(III) chloride precursor

The single source precursor tris(N,N,N’,N’-tetramethylethylenediamine)Al(III)Cl3 has been synthesized by the reaction of N,N,N’,N’-tetramethylethylenediamine (TMEDA) with AlCl3 in 3:1 molar ratio in ethanol. The precursor is stable for long periods of time and cleanly generated aluminum nitride upon pyrolysis. The pyrolysis process was optimized by varying parameters such as temperature, pressure, and the flow rate of gases (N2 and Ar). Thin films of AlN were prepared by spin coating the precursor onto Si(100) and quartz substrates followed by pyrolysis under optimized CVD conditions obtained from bulk pyrolysis. Pyrolyzed powders and films were characterized with a variety of techniques. X-ray diffraction (XRD) showed 8.5 nm grain size with a dominant 220 orientation. UV-Vis spectroscopy indicated a band gap for the AlN films of ∼5.7 eV, which is close to bulk AlN (6.1 eV). FESEM showed a smooth and homogeneous film surface and EDAX showed a 1.4:1 ratio of Al:N, respectively.

Renewable Photo-Cross-Linkable Polyester-Based Biomaterials: Synthesis, Characterization, and Cytocompatibility Assessment.

The present work consist of the synthesis of photo-cross-linkable materials, based on unsaturated polyesters (UPs), synthesized from biobased monomers from renewable sources such as itaconic acid and 1,4-butanediol. The UPs were characterized to assess the influence of polycondensation reaction temperature and cross-linking time on their final properties. For this purpose, different UV irradiation exposure periods were tested. Homogeneous, uniform, and transparent films were obtained after 1, 3, and 5 min of UV exposure. These cross-linked films were then characterized. All materials presented high gel content, which was dependent on the reaction's temperature. The thermal behaviors of the UPs were shown to be similar. In vitro hydrolytic degradation tests showed that the materials can undergo degradation in phosphate-buffered saline (PBS) at pH 7.4 and 37 °C, ensuring their biodegradability over time. Finally, to assess the applicability of the polyesters as biomaterials, their cytocompatibility was determined by using human dermal fibroblasts.

Finite element simulations of quartz crystal microbalances (QCM): from Sauerbrey to fractional viscoelasticity under water

2D finite element simulations are performed on QCM working in the thickness-shear mode and loaded with different homogeneous films. They include a purely elastic film, a viscoelastic Maxwellian liquid, viscoelastic-Voigt solid, and the fractional viscoelastic (power-law) version of each case. Unlike single-relaxation kind models, fractional viscoelasticity considers the relaxation-time spectrum often found in polymeric materials. The films are tested in air or covered with liquids of different viscosities. Two substrate thicknesses are tested: 100 nm and 500 nm, the latter being close to the condition that promotes the resonance of the adsorbed film. In all cases the simulations are compared with small-load approximation theory (SLA). The 100 nm films follow the theory closely, although significant deviations of the SLA are observed as the overtone number n increases, even in purely elastic films. We also show that it is possible to identify the viscoelastic ‘fingerprint’ of the 100 nm films in air using raw data and Sauerbrey’s equivalent thickness obtained with the QCM in the 3 < n < 13 range. These numerical data are validated by experimental measurements of crosslinked polydimethylsiloxane films with thicknesses ∼150 nm. In contrast, the 500 nm films deviate notoriously from the SLA, for all viscoelastic models and overtones, with the largest deviation observed in the elastic film. When a liquid layer covers the QCM without an adsorbed film, the only overtone that numerically reproduces the theoretical value is the fundamental, n = 1. For n > 1, strong coupling between the solid and liquid is detected, and the original vibration modes of the crystal are altered by the presence of the liquid. Finally, the numerical simulations suggest that it is possible to detect whether a viscoelastic film is formed under a liquid layer using only the information from n = 1. In these film/liquid systems we also observe the so-called missing-mass effect, although the theory and simulations exhibit different levels of impact of such effect when the liquid viscosity is high.

Thermoplastic starch/poly(butylene adipate-co-terephthalate) blown film with maltol and ethyl maltol preserving cake quality: Morphology and antimicrobial function

Maltol (MT) and ethyl maltol (EM) are flavoring compounds that release vapors into headspace, exerting antimicrobial effects and extending food shelf-life. This study investigated biodegradable films for packaged bakery quality. Biodegradable films (40 % polybutylene adipate terephthalate and 60 % thermoplastic starch) were produced via extrusion for films with varying MT and EM contents (1, 3, and 5 %). Scanning electron microscopy revealed smoother and more homogeneous film cross-sections with MT/EM, indicating reduced surface wrinkling. Fourier-transform infrared spectroscopy analysis suggested modified OH and CH stretching due to hydrogen bonding between TPS and EM/MT. The XRD pattern showed sharp MT crystallization, modifying crystal polymorphs of starch and PBAT. EM and MT films exhibited against Staphylococcus aureus after 24 h. Moreover, EM/MT films effectively delayed fungal growth in butter cake, inhibiting mold growth in butter cake more than twofold. These findings suggest that volatile compounds like MT/EM have promising potential for incorporation into PBAT/TPS films, creating active bakery packaging.

Optical, electrical, structural properties by of PFO-PMMA films loaded with TiO2 nanoparticles

The authors studied Poly (methyl methacrylate) also called PMMA films with different concentrations of Poly (9, 9′-di-n-octylfuorenyl-2, 7-diyl) also called PFO and concluded that 1% PFO blended with PMMA is the best choice for opto-electronic applications. In the present study, the authors prepared nanocomposite films of PMMA + 1% PFO + different concentrations of TiO2 nanoparticles. The resulting films were subjected to FTIR, XRD, UV–visible, fluorescence and electrical conductivity studies. The polymer matrix undergoes modifications in its molecular and microstructural characteristics as evidenced by FTIR and XRD results. The addition of TiO2 nanoparticles leads to a uniform dispersion and good interaction with the blend matrix resulting in homogeneous films. The additional peaks were found at a wavenumber of 3620 cm−1 in FTIR can be attributed to stretching vibration of TiO2. The presence of TiO2 nanoparticles is confirmed by the distinctive diffraction peaks observed at 25.4°, 37.8°, 48.3°, 54.3°, 55.2°, and 62.8°. With a shift in the absorption peak towards higher wavelengths, the nanocomposites show greater absorption in the UV and visible regions. As the concentration of TiO2 increases, the optical parameters such as absorption coefficient, extinction coefficient, Urbach energy, refractive index and optical conductivity also increase. The direct optical band gap of the PNC films decreases from 5.03 to 3.06 eV and indirect band gap decreases from 4.52 to 1.92 eV at 10 wt% of TiO2 concentration. The addition of TiO2 nanoparticles to the PFO/PMMA matrix resulted in an increase in fluorescence emission intensity. The AC electrical conductivity exhibits increasing trend with frequency in Audio-Frequency range. Thus TiO2 nanoparticles improve the overall optical, electrical, and structural properties of PFO-PMMA nanocomposites. This means that they can be used in a variety of optoelectronic and advanced optical devices.

Surface treatment processed electron transport layers for efficient Sb2S3 solar cells

Solution-processed Sb2S3 thin films and solar cell devices have recently gained popularity due to their easy procedure and outstanding final device performance. Nevertheless, although the substrate has a significant influence on thefollowing functional films, the effect of the substrate in the Sb-based solar cells appears to have not been adequately examined. In this study, we performed an interesting thioacetamide (TA)-assisted surface treatment strategy on the electron transport layer (ETL) to achieve high-quality development of Sb2S3 thin films and based solar devices. The surface treatment of ETLs resulted in a uniform surface, Zn(OH)2 impurity reduction, and excellent wettability. The above enhanced the growth of Sb2S3 thin films with features like extremely large crystal sizes (∼8 um), more homogeneous and dense film morphology, preferred crystal orientation, reduced oxygen content, and fewer defects, which benefits carrier transport. Finally, a device structure constructed of FTO/TiO2/Zn(O,S)/Sb2S3/Spiro/Au was created, resulting in an almost 30 % increase in efficiency, from 4.05 % to 5.21 %. The proposed approach not only gives new insights into generating higher-quality Sb2S3 thin films and devices, but it also presents new concepts and methods for future high-quality sulfide thin film preparation.

Synthesis and characterization of ZnO and CuO coatings for antibacterial and antiviral applications

Copper oxide (CuO) and Zinc oxide (ZnO), coating have attracted attention for their potential antiviral properties, including their ability to combat virus. This study focuses on the development and characterization of self-disinfecting surface passivation films composed of CuO and ZnO, obtained using the spin-coating technique. The research aims to develop surfaces that can actively eliminate harmful microorganisms, reducing the risk of infections, while also offering strong mechanical resistance and adhesion to withstand external factors, which is crucial for ensuring long-term effectiveness. Additionally, the microstructural properties of the elaborated films were analyzed using SEM/EDS, which stands for Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy and X-Ray diffraction analysis (XRD). The mechanical behavior was assessed through Vickers hardness and scratch resistance tests. It was found a dense and homogeneous thin films. The hardness of CuO and ZnO films were 11.14 ± 0.04 GPa, and 8.89 ± 0.04 GPa respectively. Therefore, scratching tests revealed high adhesion properties with a critical load LC1 of 1.89 ± 0.02 N and 1.04 ± 0.02 N for CuO and ZnO films respectively. Then, this study revealed that CuO and ZnO films exhibit excellent antimicrobial activity against Staphylococcus aureus ATCC 29213, as well as outstanding antiviral activity against the HSV-2 virus.

Interfacial insights: [6]-Gingerol monolayers at the air-water interface and beyond

Ginger is a culinary spice with a millennia-old tradition due to its extensive therapeutic applications, recently validated by scientific studies. In particular [6]-Gingerol, a key active molecule in ginger, exhibits extraordinary capabilities in addressing a wide spectrum of health issues. However, its therapeutic potential is limited by its rather low bioavailability. The incorporation of [6]-Gingerol into membrane systems of liposomes, micelles, or exosomes is a promising strategy to overcome this limitation. In this contribution, we report the hitherto unexplored surface properties of [6]-Gingerol at the air-water interface. Our comprehensive study, which includes a detailed analysis of surface pressure and surface potential vs. area per molecule isotherms, surface compression modulus, and Brewster Angle Microscopy, demonstrates the capability of [6]-Gingerol to form Langmuir films. These films can be transferred onto solid substrates, forming remarkably homogeneous Langmuir-Blodgett films which have been characterized by Quartz Crystal Microbalance and Atomic Force Microscopy. This study may be of interest as it paves the way for future research on introducing [6]-Gingerol into membrane systems and transporting it into living cells.

Promoting subsurface Sn incorporation at Nb(100) oxide surface sites leading to homogeneous Nb3Sn film growth for superconducting radiofrequency applications

For next-generation superconducting radiofrequency (SRF) cavities, the interior walls of existing Nb SRF cavities are coated with a thin Nb3Sn film to improve the superconducting properties for more efficient, powerful accelerators. The superconducting properties of these Nb3Sn coatings are limited due to inhomogeneous growth resulting from poor nucleation during the Sn vapor diffusion procedure. To develop a predictive growth model for Nb3Sn grown via Sn vapor diffusion, we aim to understand the interplay between the underlying Nb oxide morphology, Sn coverage, and Nb substrate heating conditions on Sn wettability, intermediate surface phases, and eventual Nb3Sn nucleation. In this work, Nb-Sn intermetallic species are grown on a single crystal Nb(100) in an ultrahigh vacuum chamber equipped with in situ surface characterization techniques including scanning tunneling microscopy, Auger electron spectroscopy, and x-ray photoelectron spectroscopy. Sn adsorbate behavior on oxidized Nb was examined by depositing Sn with submonolayer precision on a Nb substrate held at varying deposition temperatures (Tdep). Experimental data of annealed intermetallic adlayers provide evidence of how Nb substrate oxidization and Tdep impact Nb-Sn intermetallic coordination. The presented experimental data contextualize how vapor and substrate conditions, such as the Sn flux and Nb surface oxidation, drive homogeneous Nb3Sn film growth during the Sn vapor diffusion procedure on Nb SRF cavity surfaces. This work, as well as concurrent growth studies of Nb3Sn formation that focus on the initial Sn nucleation events on Nb surfaces, will contribute to the future experimental realization of optimal, homogeneous Nb3Sn SRF films.

Filler processing and mixing effects of polyoxymethylene/graphene nanocomposite on tribo-mechanical performances

Binary nanocomposites based on polyoxymethylene (POM) and graphene nanoplatelet (GNP) were fabricated to improve the tribo-mechanical performances of high-precision sliding parts in linear drive system applications. Liquid-phase exfoliation technique and surface modification by 3-aminopropyltriethoxysilane (APTES) were used to process GNP filler for improved endowment of POM/e-GNP matrix-filler interfacial adhesion. Results show that processed e-GNP at optimal 0.5 wt% loading is distributed uniformly in the matrix and enables excellent stress-transfer during the mechanical loading, increasing flexural modulus, impact strength and elongation at break by 51.3 %, 41.9 % and 24.5 %, respectively, in contrast to neat POM. Simultaneously, coefficient of friction (COF) and specific wear rate (Ws) of POM in ambient temperature were also reduced substantially by e-GNP incorporation under both dry (COF by 19.5 %, Ws by 40.6 %) and grease lubricated (COF by 38.2 %, Ws by 76.4 %) sliding conditions. Smoothened wear surface and formation of homogeneous transfer film on the steel counterface were accounted for large specific surface coverage and low-shear strength of e-GNP at the contact interface, especially during the dry sliding. In addition, the accumulated energy dissipation by frictional work was calculated in the sliding interfaces based on friction force-displacement (F-D) hysteresis loop. However, pristine POM/GNP exhibited poor matrix-filler adhesion and deteriorated composite properties due to the aggregated structure which can cause subsurface defects and serve as a failure site. The proposed new material would extend the applications of precision parts by overcoming the tribo-mechanical related issues for quieter and accurate linear motion systems.

Metal Propionate Solutions for High-Throughput Liquid-Assisted Manufacturing of Superconducting REBa2Cu3O7-δ (RE = Y, Gd, Sm, and Yb) Films.

The cost-effective synthesis of a series of metal propionate powders (copper, yttrium, barium, samarium, gadolinium, and ytterbium) is developed through single chemical reactions resulting in five novel crystalline forms. These complexes are valuable precursors for the preparation of epitaxial REBa2Cu3O7-δ (REBCO) superconducting films (here, RE = Y, Sm, Gd, and Yb) through the innovative transient liquid-assisted growth (TLAG) process based on chemical solution deposition (CSD). TLAG-CSD shows impressive results with YBa2Cu3O7-δ (YBCO), obtaining critical current densities of 2.6 MA/cm2 (77 K) on 500 nm films at unprecedented growth rates (50-2000 nm/s), boosting unprecedented high-throughput industrial production. With a cardinal concern on designing the pyrolysis toward optimal nanocrystalline films for TLAG, an analysis of the thermal behavior of the synthesized precursors is essential. Decomposition pathways for each metal propionate are established, and compatibility with TLAG-CSD is corroborated. Metal-organic solutions for these REBCO systems are successfully prepared, and their rheological properties and thermal behavior are analyzed. This work demonstrates homogeneous nanocrystalline films through propionate-based REBCO precursor solutions, including several rare-earth ions, which display exemplary chemical and microstructural characteristics crucial for TLAG, and provides a base for a wide variety of CSD-based functional oxides.

Multifunctional performance of chitosan/soy protein isolation-based films impregnated carbon dots/anthocyanin derived from purple hull pistachio for tracking and extending the shelf life of fish

The present study aimed to develop a sustainable biopolymer film that exhibits active and intelligent properties. The chitosan/soy protein isolation (Cs/SPI) based film was prepared by blending purple hull pistachio anthocyanin (PHPA) with carbon dots (CDs), which were synthesized using a by-product from purple hull pistachio (PHP) extraction. PHPA and CDs were shown to be compatible with the Cs/SPI biopolymer films. The resulting matrix was a homogeneous film with improved physico-mechanical properties. The biopolymer films were characterized by their various desirable properties, including 100% UV protection, potent antibacterial activity against S.aureus and E. coli strains with inhibition zonoe about 22.1 ± 36±0.24 mm and 20.36 ± 0.21 mm, respectively, and strong antioxidant properties (DPPH; 82.3 ± 0.1 % and ABTS; 90.6 ± 0.1 %). The film was also found to exhibit distinguishable colorimetric responses to pH 2–12 buffers and volatile ammonia. The packaging test of CS/SPI/PHPA/PHP-CDs film in scenario one (intelligent assay) for evaluation through fish freshness monitoring showed that the film's color changed from light pink (fresh fish) to yellow/brownish (spoilage fish) during storage at 4 °C and 25 °C. Also, scenario two (active assay) at 4 °C showed the ability to increase the shelf life of fish up to 12 days. The study demonstrated that the biopolymer films have exhibited exceptional adaptability, making it a highly promising option for prompt and effective on-site detection of food quality. Furthermore, the film's capacity to prolong the shelf life of fish and reduce the rate of quality degradation during storage positions it as an outstanding contender for multifunctional film applications in the food industry.

Accelerating the screening of high-entropy Co-Mn-Fe-Ni-Zn-O gradient films for highly stable NTC materials through co-sputtering combinatorial synthesis

High-entropy negative temperature coefficient (NTC) thermistor thin films, renowned for their exceptional stability, represent a significant advancement in the field of temperature measurement, facilitating the miniaturization of next-generation information and electronic devices. However, “trial and error” approach to developing multi-component NTC oxides significantly constrains the efficiency of the design process. To accelerate development process, we prepared Co-Mn-Fe-Ni-Zn-O gradient films by co-sputtering combinatorial synthesis. The effects of stoichiometric ratios on the resistance (R25), material constant (B25/50) and stability (ΔR/R0) of gradient films were visually represented through color-coded maps for straightforward and intuitive analysis. Samples close to the MnCoFe target in gradient films showed a trend of decreasing resistance and increasing material constant, both reaching 1.71 MΩ and 4083 K, respectively. The high-entropy Co21Mn17Fe19Ni21Zn22O4±δ film exhibited the lowest resistance drift rate only 2.68 % after 500 h ageing at 125 ℃. Another delightful result was that the corresponding homogeneous films, achieved through sputtering with a composite target, had a relative deviation in resistance drift rate of merely 0.18 %. This showcased the successful translation from the screening outcome to the homogeneous film, significantly accelerating the development of NTC materials via the utilization of gradient films screening.

Continuous Homogeneous Thin Liquid Film on a Single Cross-Shaped Profiled Fiber with High Off-Circularity: Toward Quick-Drying Fabrics.

Quick-drying fabrics, renowned for their rapid sweat evaporation, have witnessed various applications in strenuous exercise. Profiled fiber textiles exhibit enhanced quick-drying performance, which is attributed to the excellent wicking effect within fibrous bundles, facilitating the rapid transport of sweat. However, the evaporation process is not solely influenced by macroscopic liquid transport but also by microscopic liquid spreading on the fibers where periodic liquid knots induced by spontaneous fluidic instability significantly reduce the evaporation area. Here, a cross-shaped profiled fiber with high off-circularity, featured as multiple concavities along the fibrous longitude-axis, which enables the formation of a homogeneous thin liquid film on a single fiber without any periodic liquid knots, is developed. The high off-circularity cross-sections help overcoming Plateau-Rayleigh instability by tuning the Laplace pressure difference, further facilitated by capillary flow along the concave surface. The homogeneous thin liquid film on a single fiber is responsible for maximizing the evaporation area, resulting in excellent overall evaporation capacity. Consequently, fabrics made from such fibers exhibit rapid evaporation behavior, with evaporation rates ≈50% higher than those of cylindrical fabrics. It is envisioned that profiled fibers may provide inspiration for the manipulating homogeneous liquid films for applications in fluid coatings and functional textiles.

Innovative Application of Salophen Derivatives in Organic Electronics as a Composite Film with a Poly(3,4-Ethylenedioxythiophene)-poly(styrenesulfonate) Matrix.

In this work, we present the innovative synthesis of salophen (acetaminosalol) derivatives in a solvent-free environment by high-speed ball milling, using a non-conventional activation method, which allowed obtaining compounds in a shorter time and with a better yield. Furthermore, for the first time, the salophen derivatives were deposited as composite films, using a matrix of poly 3,4-ethylene dioxythiophene:polystyrene sulfonate (PEDOT:PSS) polymer. Significant findings include the transformation from the benzoid to the quinoid form of PEDOT post-IPA treatment, as evidenced by Raman spectroscopy. SEM analysis revealed the formation of homogeneous films, and AFM provided insights into the changes in surface roughness and morphology post-IPA treatment, which may be crucial for understanding potential applications in electronics. The optical bandgap ranges between 2.86 and 3.2 eV for PEDOT:PSS-salophen films, placing them as organic semiconductors. The electrical behavior of the PEDOT:PSS-salophen films undergoes a transformation with the increase in voltage, from ohmic to space charge-limited conduction, and subsequently to constant current, with a maximum of 20 mA. These results suggest the possible use of composite films in organic electronics.

Preparation, wear resistance, and impact toughness of homoepitaxial diamond film deposited on polycrystalline diamond compact by HFCVD method

To minimize the detrimental effects of cobalt binder on the thermal stability of polycrystalline diamond compact (PDC) under high temperature working conditions and enhance the PDC’s properties. Hot filament chemical vapor deposition diamond coated polycrystalline diamond compact (HFCVD-PDC) was prepared by depositing homogeneous epitaxial diamond film on the polycrystalline diamond layer (PCD layer) treated with cobalt binder removal. The effect of deposition pressure on the microstructure of the diamond film was investigated, and the PDC’s wear resistance was assessed using the abrasion ratio test. The drop hammer impact test was utilized to evaluate the impact toughness of the original PDC, cobalt removal PDC, and HFCVD-PDC. The results showed that a continuous and dense nanodiamond film with a cauliflower-like structure was formed on the PDC surface at the deposition pressure of 3 kPa. The abrasion ratio of the HFCVD-PDC increased by 67.44% compared to the original PDC, and by 33.29% compared to the cobalt removal PDC. Furthermore, filling nanodiamonds into the pores of cobalt removal PDC improved its impact toughness. These findings suggest that the application of homogeneous epitaxial diamond on the PCD layer can significantly improve the PDC’s wear resistance and impact toughness.

Deciphering the role of plasticizers and solvent systems in hydrophobic polymer coating on hydrophilic core

The type of plasticizer and the choice of solvent or co-solvents used for coating of a hydrophilic core can greatly impact the permeability, porosity, and mechanical strength of the polymer film. Although, Ethylcellulose (EC) is an old polymer, it is a polymer of choice for modifying the drug release due to its inherent properties. The ability of polymers like EC alone to form a diffusion-controlling membrane with good mechanical properties is limited. To modulate the drug release as per the desired profile and modify the film properties, ethylcellulose is often used with hydrophilic hypromellose (HPMC) along with plasticizers. The main focus of the current study was the identification of an appropriate solvent system and plasticizer for the ethylcellulose-hypromellose polymer combination. The study evaluated the coating solution properties, the feasibility and efficiency of the process, the physical attributes of the tablet, the surface properties of the polymer film, the in-vitro drug release and behavior, and the impact of curing time on surface properties and drug release, among other factors.The isopropyl alcohol-water mixture (9:1) produced a homogeneous film in comparison to films produced by other solvents. Although both hydrophilic and hydrophobic plasticizers produce homogeneous films, hydrophilic plasticizers have a higher rate of drug diffusion than hydrophobic plasticizers. During the tablet curing and stability study, the drug release from the polymeric film coating with triethyl citrate decreased moderately and with polyethylene glycol decreased significantly. The presence of hydrophobic plasticizers, viz., dibutyl sebacate and acetyl tributyl citrate, in the polymeric film coating does not impact drug release. For the combination of ethylcellulose and hypromellose, it was found that a mixture of isopropyl alcohol and water (9:1) worked better as a solvent for coating solutions, and hydrophobic plasticizers lower the risk associated with coating ethylcellulose and hypromellose together.

Tunable Assembly of Photocatalytic Colloidal Coatings for Antibacterial Applications.

In this study, evaporation-induced size segregation and interparticle interactions are harnessed to tune the microstructure of photocatalytic colloidal coatings containing TiO2 nanoparticles and polymer particles. This enabled the fabrication of a library of five distinct microstructures: TiO2-on-top stratification, a thin top layer of polymer or TiO2, homogeneous films of raspberry particles, and a sandwich structure. The photocatalytic and antibacterial activities of the coatings were evaluated by testing the viability of Methicillin-resistant Staphylococcus aureus (MRSA) bacteria using the ISO-27447 protocol, showing a strong correlation with the microstructure. UVA irradiation for 4 h induces a reduction in MRSA viability in all coating systems, ranging from 0.6 to 1.1 log. Films with TiO2-enriched top surfaces exhibit better resistance to prolonged exposure to disinfection and bacterial testing. The remaining systems, nonetheless, present higher antibacterial activity because of a larger number of pores and coating defects that enhance light and water accessibility for the generation and transport of reactive oxygen species. This work establishes design rules for photocatalytic coatings based on the interplay between performance and film architecture, offering valuable insights for several applications, including antibacterial surfaces, self-cleaning/antifogging applications, and water purification.

Influence of MXene Interlayer Spacing on the Interaction with Microwave Radiation

AbstractThe origin of MXene's excellent electromagnetic shielding performance is not fully understood. MXene films, despite being inhomogeneous at the nanometer scale, are often treated as if they are compared to bulk conductors. It is reasonable to wonder if the treatment of MXene as a homogeneous material remains valid at very small film thickness and if it depends on the interlayer spacing. The goal of the present work is to test if the homogeneous material model is applicable to nanometer‐thin Ti3C2Tx MXene films and, if so, to investigate how the model parameters may depend on variations in MXene interlayer spacings. MXene films containing flakes with interlayer spacing between 1.9 and 5.5 Å have been prepared using various intercalating agents. It is shown that modeling the films as being homogeneous agrees with experimental tests in the microwave frequency range. Microwave conductivity and dielectric constant parameters are estimated for the homogeneous film model by fitting measured results. The direct current (DC) conductivity matches the estimated microwave conductivity on the order of magnitude. A highly effective dielectric constant provides a good fit for the lower conductivity MXene films. Optical absorption agrees with the homogeneous material model of thin films as well.

Fabrication and characterization of active gelatin-based films integrated with nanocellulose-stabilized Pickering emulsion containing Oliveria Decumbens Vent. essential oil

Stabilizing essential oils (EOs) within biodegradable matrices to create homogeneous and stable films with desirable properties is challenging due to the hydrophobic nature of EOs, which hinders their uniform infusion into the matrix. In this study, we investigated the feasibility of creating active films made of gelatin, infused with nanocellulose-stabilized Pickering emulsion (PE) containing Oliveria Decumbens Vent. essential oil (OEO). The Pickering emulsion effectively stabilized the 50% v/v of OEO, which was subsequently incorporated into a gelatin film at 0, 3, 5, 7, and 9% v/v, to produce active films. FTIR data showed that the OEO-PE was physically trapped in the film matrix through hydrogen bonds, which was also verified by SEM micrographs. The addition of OEO-PE notably changed the films' mechanical properties, leading to reduced tensile strength and enhanced elongation (P < 0.05) with no significant impact on their water vapor permeability. The incorporation of OEO endowed the film matrix with high antioxidant and antibacterial activity against E. coli and S. aureus. Thermal analysis using differential scanning calorimetry showed a 36–171 °C endothermic peak in all films, due to water evaporation and melting. The gelatin film containing 9% OEO-PE exhibited superior physical properties, enhanced water resistance, and excellent antibacterial and antioxidant activity.