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Nanoporous Pt films fabricated by oblique angle deposition hold potential as electrocatalysts in various energy-related fields owing to their high surface area, structural stability, and adequate conductivity. In this study, we investigated the morphology, porosity, and electrical conductivity of nanoporous Pt thin films and systematically studied their interrelationships. Specifically, we revealed an in-plane anisotropy in the electrical conductivity that correlates with the surface morphology of the film. This anisotropy was evident in the resistance measurements along the in-plane lateral and vertical directions, which aligned well with our simple model. The results emphasize the significance of film morphology in determining the film's electrical properties. This study contributes to the understanding of the physical properties of Pt films fabricated via oblique angle deposition and offers valuable insights for designing nanoporous films for various applications. [ABSTRACT FROM AUTHOR]

Abstract Nanoporous Pt films fabricated by oblique angle deposition hold potential as electrocatalysts in various energy-related fields owing to their high surface area, structural stability, and adequate conductivity. In this study, we investigated the morphology, porosity, and electrical conductivity of nanoporous Pt thin films and systematically studied their interrelationships. Specifically, we revealed an in-plane anisotropy in the electrical conductivity that correlates with the surface morphology of the film. This anisotropy was evident in the resistance measurements along the in-plane lateral and vertical directions, which aligned well with our simple model. The results emphasize the significance of film morphology in determining the film’s electrical properties. This study contributes to the understanding of the physical properties of Pt films fabricated via oblique angle deposition and offers valuable insights for designing nanoporous films for various applications.

This proposal outlines a novel approach for fabricating porous films designed specifically for therapeutic formulations. These biodegradable films are sourced from Retama Raetam shrub branches through the innovative Super-critical Anti-Solvent (SAS) process. Renowned for their efficacy in managing hypertension and serving as diuretics, these films also excel in enhancing the entrapment of additional active ingredients. Furthermore, they enhance the entrapment of other active ingredients, thereby improving the stability and composition of tablets or capsules. Notably, the resulting film displays an exceptionally narrow and uniform distribution of pore sizes. Employing conditions of 10MPa and 40°C, carbon dioxide is utilized as the antisolvent to fabricate thin films sourced from Retama Raetam. These films boast a median area of approximately 7µm², underscoring their precise and consistent characteristics. [ABSTRACT FROM AUTHOR]

This study explores the potential of LDH flakes decorated with metallic oxide nanoparticles to function as both anti-corrosion barriers against chloride anions and heterogeneous photocatalysts for tetracycline degradation under visible light. The process involves modifying the primarily MgO-based inorganic porous film by growing a MgFe LDH film, followed by the individual and dual incorporation of SnO2 and WO3 nanoparticles. The dual incorporation of these nanoparticles into the LDH matrix leads to synergistic interactions, effectively sealing pre-existing defects within LDH flakes and facilitating the in-situ formation of catalytic sites through oxidation and the induction of surface oxygen vacancy defects, which synergistically contribute to the enhancement of both electrochemical and photocatalytic activities. The enhanced electrochemical stability is reflected in a significant reduction in corrosion current density by 4 orders of magnitude compared to unmodified porous film. Additionally, the decorated film demonstrates sustained photocatalytic functionality, achieving significant degradation (95.5%) of tetracycline within two hours. This study presents a novel approach, highlighting the dual effectiveness of LDHs decorated by dual metal oxides as an anti-corrosive agent and photocatalyst, with promising implications for environmental remediation and wastewater purification.

A microbial fuel cell (MFC) is a device that converts chemical energy into electrical energy through the catalytic processes of microorganisms. In this study, flexible and porous WO3/CNTs-Graphite-PVC film was fabricated through uniform adding of Zn powder into matrix of carbon nanotubes-graphite- Polyvinyl Chloride) PVC (film followed by selective dissolving of Zn from the film structure in acidic solution and finally electrodeposition of WO3 (Tungsten trioxide) into previously porous CNTs-Graphite-PVC film. Surface morphology studies showed that the flexible film has rough and porous structure and carbon nanotubes are uniformly present as electron conduction channels within the composite film. Studies also showed that porous WO3/MWCNTs-Graphite-PVC film as a bioanode in MFC at resistance of 1000 ohms and current density of 900 mA/m2 has a power density of 324 mW/m2. The method presented in this research can be used as a suitable method for preparing of suitable electrocatalysts based on commercial graphite powder in microbial fuel cells.

Porous Ni0 nanofilms with different surface morphologies have great potential for application in the field of elect rochromism. This article reports the preparation of porous Ni0 thin films by ad ding non ionic surfactant TX-1 00 to NiSO-i • 6H2 0 aqueous solution. The morphology and composition of Ni0 thin films without surfactants and with TX-1 00 were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Electrochemical workstation and UV visible spectrophotometer were used to test the electrochromic performance. The results indicate that the addition of TX-100 can reduce the pore size and make the surface of porous Ni0 films denser, providing a larger specific surface area and more active sites, improving optical properties, and to some extent enhancing the cyclic stability of Ni0 films. At the wavelength of 600 nm, the maximum light modulation amplitude of the Ni0 film with TX-1 00 added is 68.88%, which is 8. 58% higher than that of the Ni0 film without surfactant added. [ABSTRACT FROM AUTHOR]

• LDH flakes provided efficient sealing of the porous layer, thereby improving durability. • SnO 2 and WO 3 were incorporated simultaneously in LDH flakes under hydrothermal conditions. • LDH-SnO 2 -WO 3 exhibited exceptional electrochemical and photocatalytic performance. • Computational analyses elucidated the detailed interactions between metal oxides and LDH surfaces. This study explores the potential of LDH flakes decorated with metallic oxide nanoparticles to function as both anti-corrosion barriers against chloride anions and heterogeneous photocatalysts for tetracycline degradation under visible light. The process involves modifying the primarily MgO-based inorganic porous film by growing a MgFe LDH film, followed by the individual and dual incorporation of SnO 2 and WO 3 nanoparticles. The dual incorporation of these nanoparticles into the LDH matrix leads to synergistic interactions, effectively sealing pre-existing defects within LDH flakes and facilitating the in-situ formation of catalytic sites through oxidation and the induction of surface oxygen vacancy defects, which synergistically contribute to the enhancement of both electrochemical and photocatalytic activities. The enhanced electrochemical stability is reflected in a significant reduction in corrosion current density by 4 orders of magnitude compared to unmodified porous film. Additionally, the decorated film demonstrates sustained photocatalytic functionality, achieving significant degradation (95.5%) of tetracycline within two hours. This study presents a novel approach, highlighting the dual effectiveness of LDHs decorated by dual metal oxides as an anti-corrosive agent and photocatalyst, with promising implications for environmental remediation and wastewater purification. [Display omitted] [ABSTRACT FROM AUTHOR]

A microbial fuel cell (MFC) is a device that converts chemical energy into electrical energy through the catalytic processes of microorganisms. In this study, flexible and porous WO3/CNTs-Graphite-PVC film was fabricated through uniform adding of Zn powder into matrix of carbon nanotubes-graphite-Polyvinyl Chloride) PVC ( film followed by selective dissolving of Zn from the film structure in acidic solution and finally electrodeposition of WO3 (Tungsten trioxide) into previously porous CNTs-Graphite-PVC film. Surface morphology studies showed that the flexible film has rough and porous structure and carbon nanotubes are uniformly present as electron conduction channels within the composite film. Studies also showed that porous WO3/MWCNTs-Graphite-PVC film as a bioanode in MFC at resistance of 1000 ohms and current density of 900 mA/m² has a power density of 324 mW/m². The method presented in this research can be used as a suitable method for preparing of suitable electrocatalysts based on commercial graphite powder in microbial fuel cells. [ABSTRACT FROM AUTHOR]

Imine‐based covalent organic frameworks (COFs) are crystalline porous materials with prospective uses in various devices. However, general bulk synthetic methods usually produce COFs as powders that are insoluble in most of the common organic solvents, arising challenges for the subsequent molding and fixing of these materials on substrates. Here, we report a novel synthetic methodology that utilizes an electrogenerated acid (EGA), which is produced at an electrode surface by electrochemical oxidation of a suitable precursor, acting as an effective Brønsted acid catalyst for imine bond formation from the corresponding amine and aldehyde monomers. Simultaneously, it provides the corresponding COF film deposited on the electrode surface. The COF structures obtained with this method exhibited high crystallinities and porosities, and the film thickness could be controlled. Furthermore, such process was applied for the synthesis of various imine‐based COFs, including a three‐dimensional (3D) COF structure. [ABSTRACT FROM AUTHOR]

Heat exchange tubes require a porous inner surface to maximize their boiling performance. However, in addition to the geometric limitations of long and narrow tubes, producing porous inner surfaces remains challenging for conventional coating technologies. To prepare porous coatings on the inner surface of narrow tubes, a novel continuous wire electrical explosion spraying device was developed. The charging voltage influenced the overheat factor and expansion velocity of the aluminum wire, which simultaneously affected the size, temperature, and velocity of the explosive products deposited inside medium-carbon steel tubes. These effects ultimately impacted the flattening degree and microstructure of the deposited material. Experiments revealed that the porosity, wettability, adhesion, and rate of increase in coating surface area are all superior at a charging voltage of 12.0 kV. Thus, coatings prepared at this charging voltage can effectively improve the heat transfer of the tube. Our study also provides insights into the effects of charging voltage on the microstructure of deposited film, which may be extended to the coatings of other complex components. [ABSTRACT FROM AUTHOR]

We have used known theoretical approaches, namely, Grosberg–Khokhlov and Flory theory, for description mechanical properties of porous polymer films in electrolyte solvents. In both approaches, in good solvents, with the increase in the swelling ratio α, the Young's modulus asymptomatically decreases to zero, i.e. films are softened. In Grosberg–Khokhlov's theory, it has been shown that the Young's modulus is maximal at the swelling ratio α = 1 that corresponds to the dry film or the film in θ-solvent. In this theory, the effect of hardening of porous films (the poroelastic effect) is impossible in any good solvents, and the film is always softened. However, in Flory theory, such solvent may be always selected where the poroelastic effect may be realized. [ABSTRACT FROM AUTHOR]

We present a novel terahertz (THz) Fabry–Perot (FP) microcavity biosensor that uses a porous polytetrafluoroethylene (PTFE) supporting film to improve microorganism detection. The THz FP microcavity confines and enhances fields in the middle of the cavity, where the target microbial film is placed with the aid of a PTFE film having a dielectric constant close to unity in the THz range. The resonant frequency shift increased linearly with increasing amount of yeasts, without showing saturation behavior under our experimental conditions. These results agree well with finite-difference time-domain (FDTD) simulations. The sensor's sensitivity was 11.7 GHz/μm, close to the optimal condition of 12.5 GHz/μm, when yeast was placed at the cavity's center, but no frequency shift was observed when the yeast was coated on the mirror side. We derived an explicit relation for the frequency shift as a function of the index, amount, and location of the substances that is consistent with the electric field distribution across the cavity. We also produced THz transmission images of yeast-coated PTFE, mapping the frequency shift of the FP resonance and revealing the spatial distribution of yeast. [ABSTRACT FROM AUTHOR]

Porous films were fabricated from poly(L-lactide) (PLLA)-1,4-dioxane-dimethylacetamide ternary systems via thermally induced phase separation (TIPS) followed by using freeze extraction. The effect of processing parameters including freezing temperature, quenching time, and the film thickness was investigated on the physical, mechanical, and morphological properties of the porous films. The primary objective of increase in the film thickness is to cause a decreased temperature gradient between external layer and internal layers at the same temperature (according to Fourier's law) and to decrease the growth rate of the solvent-rich phase. The results revealed that increasing thickness from 1200 to 1600 µm at − 20 °C for 6 h resulted in producing pore sizes 200 nm and nanofibrous (> 200 nm fiber diameter) instead of 400 nm and nanofibrous (< 100 nm fiber diameter). The nanofibrous (< 100 nm) exhibit higher porosity and water absorption, and lower tensile strength than the nanofibrous (> 200 nm). As a result of the high film thickness, decreasing temperature from − 20 to − 45 °C (increasing temperature gradient), and increasing time from 6 to 24 h, it is indicated that the phase separation happens via the coarsening process and forms nanospindle structure with the pore size 800 nm. [ABSTRACT FROM AUTHOR]

Scar formation has always been a difficult point to overcome in the field of clinical wound care. Here, we present an ellipsoidal porous patch with cell inducing ability for inhibiting scar formation. The patch was prepared by stretching a poly (lactic-co-glycolic acid) (PLGA) inverse opal film at the glass transition temperature to form a neatly arranged three-dimensional ellipsoidal porous structure. Such anisotropic structure showed dramatic capability in directing cell growth and arrangement by reconstructing cell morphology. Besides, the proliferation of cells growing on the stretched patch was significantly suppressed without cell cytotoxicity. In addition, benefitting from the abundant and connected nanopores, the patch could be imparted with a potent ability to promote cell migration by encapsulating fibroblast growth factor 2 (FGF2) via the second filling of functional gelatin methacryloyl (GelMA) hydrogel into its scaffold. In a typical scar model, we have demonstrated that the resultant patch performed well in inhibiting scar formation characterized by inhibiting the excessive proliferation of fibroblasts, decreasing the deposition of type I collagen, reducing the scar index and achieved complete tissue reconstruction. These results indicate the anisotropic inverse opal patch has an excellent application prospect in inhibiting scar formation during wound repair.

The Kubelka-Munk function is simple but it ignores the film's thickness, so its applications are greatly limited. Though the exact relationship between the Kubelka-Munk function and the thickness can be derived from a differential model, it is too complex to be practically used. Here a modification is suggested by taking the thickness effect and the temperature effect into account, and the validity is widely enlarged. The modified Kubelka-Munk theory can be used as a colormatching model for colorful fabrics. If the porosity of the film is considered, a fractal modification with two-scale fractal derivative has to be adopted. [ABSTRACT FROM AUTHOR]

In this study, the reliability characteristics of metal-insulator-semiconductor (MIS) capacitor structures with low-dielectric-constant (low-k) materials have been investigated in terms of metal gate area and geometry and thickness of dielectric film effects. Two low-k materials, dense and porous low-k films, were used. Experimental results indicated that the porous low-k films had shorter breakdown times, lower Weibull slope parameters and electric field acceleration factors, and weaker thickness-dependence breakdowns compared to the dense low-k films. Additionally, a larger derivation in dielectric breakdown projection model and a single Weilbull plot of the breakdown time distributions from various areas merging was observed. This study also pointed out that the porous low-k film in the irregular-shaped metal gate MIS capacitor had a larger dielectric breakdown time than that in the square- and circle-shaped samples, which violates the trend of the sustained electric field. As a result, another breakdown mechanism exists in the irregular-shaped sample, which is required to explore in the future work. [ABSTRACT FROM AUTHOR]

Nanostructuring of metals is nowadays considered as a promising strategy towards the development of materials with enhanced electrochemical performance. Porous and fully dense CuNi films were electrodeposited on a Cu plate by electrodeposition in view of their application as electrocatalytic materials for the hydrogen evolution reaction (HER). Porous CuNi film were synthesized using the hydrogen bubble template electrodeposition method in an acidic electrolyte, while fully dense CuNi were electrodeposited from a citrate-sulphate bath with the addition of saccharine as a grain refiner. The prepared films were characterized chemically and morphologically by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The Rietveld analysis of the XRD data illustrates that both CuNi films have a nanosized crystallite size. Contact angle measurements reveal that the porous CuNi film exhibits remarkable superhydrophobic behavior, and fully dense CuNi film shows hydrophilicity. This is predominately ascribed to the surface roughness of the two films. The HER activity of the two prepared CuNi films were investigated in 1 M KOH solution at room temperature by polarization measurements and electrochemical impedance spectroscopy (EIS) technique. Porous CuNi exhibits an enhanced catalysis for HER with respect to fully dense CuNi. The HER kinetics for porous film is processed by the Volmer–Heyrovsky reaction, whereas the fully dense counterpart is Volmer-limited. This study presents a clear comparison of HER behavior between porous and fully dense CuNi films. [ABSTRACT FROM AUTHOR]

Designing and fabricating efficient electromagnetic interference (EMI) shielding materials becomes a significant and urgent concern. Hence, a novel ultrathin, flexible, and oxidation-resistant MXene-based graphene (M-rGX) porous film is successfully fabricated by electrostatic self-assembly between MXene and graphene oxide (GO) nanosheets, and subsequently thermal annealing under hydrogen-argon atmosphere. The rapid breakaway of functional groups on GO and MXene sheets induces formation of porous conductive network in film, thereby facilitating efficient shielding for incident electromagnetic waves. The optimal absolute shielding effectiveness (SSE/t) value of 76,422 dB·cm2·g−1 can be achieved at a thinner thickness of 15 μm. More importantly, the effective removal of functional groups on MXene conspicuously improves the oxidation resistance of the film, endowing it with an excellent durability (12 months) in EMI shielding performance. [ABSTRACT FROM AUTHOR]

Polycaprolactone (PCL) is one of the promising linear aliphatic polyesters which can be used as mulching film. Although it has suitable glass transition temperature and good biodegradability, further practical applications are restricted by the limited temperature-increasing and moisturizing properties. The rational design of the PCL structure is a good strategy to enhance the related properties. In this study, thermally-induced phase separation (TIPS) was introduced to fabricate a PCL nanoporous thin film. The introduction of a nanoporous structure on the PCL surface (np-PCL) exhibited enhanced temperature-increasing and moisturizing properties when used as mulch film. In detail, the average soil temperature of np-PCL was increased to 17.81 °C, when compared with common PCL of 17.42 °C and PBAT of 17.50 °C, and approaches to PE of 18.02 °C. In terms of water vapor transmission rate, the value for np-PCL is 637 gm−2day−1, which was much less than the common PCL of 786 and PBAT of 890 gm−2day−1. As a result, the weed biomass under the np-PCL was suppressed to be 0.35 kg m−2, almost half of the common PCL and PBAT. In addition, the np-PCL shows good thermal stability with an onset decomposition temperature of 295 °C. The degradation mechanism and rate of the np-PCL in different pH environments were also studied to explore the influence of nanoporous structure. This work highlights the importance of the nanoporous structure in PCL to enhance the temperature-increasing and moisturizing properties of PCL-based biodegradable mulching film. [ABSTRACT FROM AUTHOR]

• Double-layer WO3@CQDs porous film was synthesised on the optical fiber. • ppb-level 2-butanone can be detected at room temperature. • The mechanism of WO3@CQDs on 2-butanone is explained by DFT results. • The mechanism of WO3@CQDs porous films on 2-butanone was described in detail. In this study, a hollow malposition structure (HMS) optical fiber 2-butanone gas sensor based on double-layer WO 3 @CQDs porous film is proposed, and realizes the ppb detection of 2-butanone gas at room temperature. The HMS can excite the evanescent field and sense the gas adsorption on the fiber surface. The experimental results show sensitivity of 3.09 pm/ppm for this HMS optical fiber gas sensor based on double-layered WO 3 @CQDs porous film, which is 6.05 times higher than that of the sensor coated with single-layer WO 3 @CQDs porous film. In addition, a limit of detection (LOD) reaches 500 ppb. The response time is 11.7 s and the recovery time is 5.72 s. Density functional theory (DFT) results show that the modification of CQDs improves the adsorption capacity of WO 3 @CQDs for 2-butanone gas molecules and changes the refractive index of the material. The sensor has the advantages of small volume, high sensitivity and a low LOD, which is of great significance for the detection of trace 2-butanone gas. [ABSTRACT FROM AUTHOR]

The characterization of the mechanical properties of soft films is of great importance for their applications. In our previous research, we demonstrate the existence of a maximum load occurring during the indentation process of a perforated film by a spherical indenter. Based on this result, an approach to obtain the shear modulus of the film material using the method of finite element analysis has been proposed. However, our previous work does not consider the effect of friction between the film and the indenter, which has a significant influence on the value of the maximum load. Here, a theoretical model is presented which takes into account the role of friction. The reliability and accuracy of the theoretical model are validated by comparison with simulations and experimental results. In addition, the indenter eccentricity and round hole shape deviations which commonly occur in actual indentation tests, are investigated by combining indentation test measurements with finite element analysis. The performance of this method on porous films is also analyzed experimentally and numerically. The results reveal that this indentation method is still effective for porous films. This work provides a fundamental understanding of the mechanism of the indentation method and is expected to provide a new perspective for local characterization of films, even with multiple holes. • A theoretical model of the indentation method considering the effects of friction is proposed. • The indenter eccentricity and round hole shape deviation are investigated. • The validity of the theoretical model is verified by simulations and experimetns. • The indentation method is extended to porous materials by numerical and experimental analysis. [ABSTRACT FROM AUTHOR]

• Ordered AAO structures with interpore distance of 385–420 nm forms in 1 m H 3 PO 3. • The apparent activation energy of al anodizing in 1 m H 3 PO 3 is 65 kJ/mol. • Novel approach to two stage anodizing at high voltages is proposed. • AAO crystallizes in γ-, δ-, and θ-phases at 820 °C and in α-Al 2 O 3 at 1310 °C. • Ordered arrangement of pores is preserved in α-Al 2 O 3 after annealing at 1310 °C for 60 h. Aluminium anodizing in phosphonic acid is known to produce anodic aluminium oxide (AAO) honeycomb structures with large interpore distances. However, detailed information on two-stage anodizing in phosphonic acid and annealing conditions required for the crystallization of AAO cell walls have not been reported yet. Here, the kinetics of aluminium anodizing in 1 M phosphonic acid and the thermal behaviour of the resulting AAO have been studied in detail. The apparent activation energy of aluminium anodizing is 65 kJ mol–1 and the AAO growth rate reaches 15 µm h–1 before oxide "burning". A universal approach for stable two-stage anodizing at high voltages allowing to prevent porous structure rearrangement in the upper part of AAO is proposed. It involves the preliminary formation of a dense barrier alumina layer by anodizing in a weak acid electrolyte before the second anodizing step in phosphonic acid. The crystallization pathways of AAO obtained in phosphonic acid electrolyte are revealed based on differential scanning calorimetry, X-ray diffraction, and solid-state nuclear magnetic resonance techniques. The designed annealing program allows one to preserve the honeycomb porous structure after the crystallization of AAO in corundum at 1310 °C for 60 h. AAO obtained in phosphonic acid possesses high thermal stability and, thus, is promising as a support for gas sensors and fuel cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Devices that are used in the aerospace industry must operate in extreme conditions, so it is important to understand how the properties of materials change under the influence of radiation and low temperatures. Anodic aluminum oxide, due to its mechanical and dielectric properties, is widely used in electronic devices with a high degree of integration. Radiation exposure can lead to degradation of the electrophysical parameters of dielectric films and can also change their chemical composition. The methods for studying the effect of radiation exposure on the dielectric properties of films are shown in this article. The research has been carried out and the results of the influence of α-particles on the dielectric properties of a porous film of anodic aluminum oxide during the influence of low temperature are presented.

Porous films were fabricated from the poly (styrene-co-acrylonitrile) (SAN) / chloroform system containing various nonsolvents (2-propanol, PEG400, and their mixtures) by dry casting (evaporation induced phase separation, EIPS) method. The effects of polymer concentration, type and concentration of nonsolvents, and the mixture of nonsolvents on the film structure were studied. The films had an average pore diameter of 0.9–2.1 μm and a porosity of up to 56%. The phase diagram of the systems was drawn experimentally and theoretically and used to elucidate the process. The nonsolvent efficiency for creating pores (EfNS) and the approaching ratio of solution (ARSolution) were also presented and used. The skin layer thickness decreased and porosity, film thickness, and EfNS increased as the initial solution composition approached the two-phase region (increasing ARSolution). EfNS of PEG was higher than 2-propanol. [ABSTRACT FROM AUTHOR]

Mechanical properties of hyaluronic acid (HA) hydrogels are too poor to be prepared as an ultra-thin hydrogels, so to provide a supporting skeleton for them is important. Herein, the porous film based on chitosan(CS)、PEG-20000 and graphene oxide (GO) were prepared for ultra-thin hydrogels. CS is a suitable polymer to prepare films. The added PEG-20000 endowed the film porosity. And the addition of GO improved the mechanical of the film. When CS:PEG = 3:2 and the GO solution proportion was 15%, the porous film exhibited the best comprehensive properties, with a tensile strength of 5.593 MPa, an elongation at break of 45.833%, a water permeation of 1.4099 g at 12 h, a porosity of 62.3% and an average pore size of 1.88 um. Blood compatibility experiments and cell experiments have proved that the film hydrogel has strong biocompatibility, indicating it can be a promising biomaterial. [ABSTRACT FROM AUTHOR]

The rapid development of the Internet of Things and wearable electronics has generated growing interest in creating high-performance and visually striking polymer thermoelectric (TE) devices. However, existing polymer TE materials have yet to fully meet these diverse demands. In this study, imprinted porous polymer films are introduced that exhibit both high TE performance and a spectrum of structural colors. The porous architecture not only preserves excellent charge transport properties but also significantly enhances phonon-like scattering, resulting in a more than 50% reduction in thermal conductivity for the PDPPSe-12 film. This leads to a 170% increase in the figure of merit (ZT), achieving a peak value of 0.52 at 363 K. Furthermore, the highly ordered porous structure imparts the PDPPSe-12 films with both a wide range of structural colors and remarkable stretchability, making them ideal for wearable TE generators. This approach is widely applicable to various polymeric systems, offering a novel strategy for advancing state-of-the-art plastic TE materials through microstructural engineering., (© 2024 Wiley‐VCH GmbH.)

Two-dimensional (2D) niobium carbide, Nb4C3Tx (Tx: O, OH, and F), a representative member of the 43 MXene structural motif, has shown promising electrochemical performance in acidic electrolytes. The capacitive performance of Nb4C3Tx in neutral aqueous electrolytes has been reported as moderate, but little effort has been made to improve it. In this paper, we report a method to introduce nanopores (pinholes) in Nb4C3Tx MXene flakes by adjusting the etching time. The pinholes generated during the etching process improve ion diffusion pathways, which are otherwise hindered by the restacking of the 2D flakes. The “holey Nb4C3Tx” shows a 50 % improved rate capability at charge/discharge time scales of 1–2 s in 1 M Li2SO4, Na2SO4, and (NH4)2SO4 electrolytes. Our strategy of controlling the permeability of Nb4C3Tx sheets can potentially be applied to other MXenes, providing guidance for improving the capacitance and rate capability of 2D materials.

We present a novel terahertz (THz) Fabry–Perot (FP) microcavity biosensor that uses a porous polytetrafluoroethylene (PTFE) supporting film to improve microorganism detection. The THz FP microcavity confines and enhances fields in the middle of the cavity, where the target microbial film is placed with the aid of a PTFE film having a dielectric constant close to unity in the THz range. The resonant frequency shift increased linearly with increasing amount of yeasts, without showing saturation behavior under our experimental conditions. These results agree well with finite-difference time-domain (FDTD) simulations. The sensor’s sensitivity was 11.7 GHz/μm, close to the optimal condition of 12.5 GHz/μm, when yeast was placed at the cavity’s center, but no frequency shift was observed when the yeast was coated on the mirror side. We derived an explicit relation for the frequency shift as a function of the index, amount, and location of the substances that is consistent with the electric field distribution across the cavity. We also produced THz transmission images of yeast-coated PTFE, mapping the frequency shift of the FP resonance and revealing the spatial distribution of yeast.

Self-assembled monolayers (SAMs) are emerging as materials that are candidates of barriers used in back-end-of–line interconnects of integrated circuits for future generations. In this study, SAMs were formed on the SiO2 and porous SiOCH (p-SiOCH) films by using decyltrimethoxysilane (DTMOS) precursor in vapor phase at a temperature of 100 °C. The effects of the formation of SAMs at the surfaces of SiO2 and p-SiOCH films on the electrical characteristics were characterized and compared. With O2 plasma irradiation, SAMs could successfully form on both SiO2 and p-SiOCH films, thereby enhancing the adhesion and dielectric breakdown field. In the p-SiOCH films, SAMs sealed the surface pores and had higher coverage, promoting the effectiveness of the Cu barrier. In the Cu/porous low-k integrated interconnects for advanced technological nodes, therefore, SAMs are promising emerging materials acting as a barrier and adhesive. On the other hand, for SiO2 films, SAMs weakened the barrier; however, they can act as an interfacial adhesion enhancer. [ABSTRACT FROM AUTHOR]

Photoluminescence color filter (PLCF) array using quantum color converters is recently a strong candidate to replace traditional absorptive CF in various display applications. PLCF displays are expected to have higher efficiency and wider color gamut. Ink‐jet printing is a versatile and low‐cost method to pattern color converting films, but uniformity problem is to be concerned. To utilize perovskite nanoparticles (PNP) and low dimension semiconductor material, maintaining good photoluminescence (PL) properties in the processing and long‐term stability is challenging. In our work, we use a porous polymer film (PF) as the ink jet printing template. Capillary effect of the sub‐micron pores in the PF promotes uniform coffee‐ring free printing with reduced size (<50 μm). Without using any mask or bank structures, green PNP and red Quantum Rod (QR) arrays can be printed with high quality. The PF CF is endowed with good PL stability for more than 80 days. In terms of device application, ambient contrast ratio become problematic considering the ambient light excitation of color converters. We adapted bottom CF structure for LCD to solve this problem. A LCD equipped with a printed full‐color PNP‐QR PF CF was demonstrated. The color gamut of the design can reach 96.9% BT.2020. [ABSTRACT FROM AUTHOR]

The paper presents the results of an experimental investigation of the morphology of copper and silver thin films synthesized by the substitution reaction method. Silver films were synthesized by immersing polished substrates of copper (M1 brand) into silver nitrate solution. Copper films were synthesized by immersing substrates of iron (electrolytic iron brand) and also of iron with vacuum deposited tin film of 5 μm thick into copper vitriol solution. The morphology of synthesized films was analyzed by a scanning electron microscope. The research has shown that the metal films with the thickness of around 1 μm are formed 2 seconds after the reaction start point. The films consist of crystal micro- and nanodendrites. The silver films also contain crystalline plates of silver oxide with characteristic size up to 2 μm. With an increase of reaction time the metal layers are compacted. And minimal pore sizes in this case are 20 nm. The synthesized films can be used for the creation of semiconductor-metal micro- and nanostructures for photocatalytic water splitting. Such films can be also applied in chemical sensors and biosensors for surface enhancement of Raman scattering.

Two-dimensionally Ordered macroporous films have attracted attention for their potential application such as sensors and optoelectronic devices. Here, highly ordered ZnO nanonets film were successfully prepared by a facile method, which uses monolayer colloidal crystal template composed of polystyrene spheres and sol-gel spin-coating method. Furthermore, ZnO nanonets-based ultraviolet photodetector are constructed, which showed high on/off current ratio of 2.7 × 105 under 370 nm UV light illumination with an intensity of 0.85 mW/cm2.

Passive radiative cooling and triboelectric generation provide a way to achieve zero-energy cooling and sustainable electricity generation, respectively. However, they are frequently studied independently and lack integration. Herein, a scalable porous film for thermal insulation, passive radiative cooling and triboelectric generation has been developed using a facile emulsion polymerization method. Abundant micrometer size air holes within the multifunction porous film (MFPF) result in a low thermal conductivity of 0.05 W/(m·K), and strong scattering occurs at the interface between the air holes and Ecoflex, resulting in high solar reflectance. Simultaneously, a high infrared emittance of 0.95 is attained owing to the molecular vibrations of Ecoflex. The MFPF delivers a theoretical net passive radiative cooling power of 29.04 W/m2 and 122.68 W/m2 during the daytime and nighttime. Additionally, it achieves an actual temperature drop of approximately 4.5 °C under direct sunlight on a clear day. Moreover, a triboelectric effect of a maximal power density of 0.03 W/m2 is achieved due to the triboelectric-negative nature of Ecoflex. This film can achieve passive radiative cooling in the summer while more effectively blocking heat penetration due to the significant temperature difference between the outdoors and indoors. Meanwhile, the film can convert sustainable energy into electricity. • A scalable porous film with thermal insulation, passive radiative cooling and triboelectric generation. • The film has low thermal conductivity of 0.05 W/(m·K), which more effectively blocking heat penetration. • The film has theoretical passive radiative cooling power of 29.04 W/m2 and 122.68 W/m2 during the daytime and nighttime. • A triboelectric effect of a maximal power density of 0.03 W/m2 is achieved. [ABSTRACT FROM AUTHOR]

In this study, the reliability characteristics of metal-insulator-semiconductor (MIS) capacitor structures with low-dielectric-constant (low-k) materials have been investigated in terms of metal gate area and geometry and thickness of dielectric film effects. Two low-k materials, dense and porous low-k films, were used. Experimental results indicated that the porous low-k films had shorter breakdown times, lower Weibull slope parameters and electric field acceleration factors, and weaker thickness-dependence breakdowns compared to the dense low-k films. Additionally, a larger derivation in dielectric breakdown projection model and a single Weilbull plot of the breakdown time distributions from various areas merging was observed. This study also pointed out that the porous low-k film in the irregular-shaped metal gate MIS capacitor had a larger dielectric breakdown time than that in the square- and circle-shaped samples, which violates the trend of the sustained electric field. As a result, another breakdown mechanism exists in the irregular-shaped sample, which is required to explore in the future work.

Nanostructuring of metals is nowadays considered as a promising strategy towards the development of materials with enhanced electrochemical performance. Porous and fully dense CuNi films were electrodeposited on a Cu plate by electrodeposition in view of their application as electrocatalytic materials for the hydrogen evolution reaction (HER). Porous CuNi film were synthesized using the hydrogen bubble template electrodeposition method in an acidic electrolyte, while fully dense CuNi were electrodeposited from a citrate-sulphate bath with the addition of saccharine as a grain refiner. The prepared films were characterized chemically and morphologically by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The Rietveld analysis of the XRD data illustrates that both CuNi films have a nanosized crystallite size. Contact angle measurements reveal that the porous CuNi film exhibits remarkable superhydrophobic behavior, and fully dense CuNi film shows hydrophilicity. This is predominately ascribed to the surface roughness of the two films. The HER activity of the two prepared CuNi films were investigated in 1 M KOH solution at room temperature by polarization measurements and electrochemical impedance spectroscopy (EIS) technique. Porous CuNi exhibits an enhanced catalysis for HER with respect to fully dense CuNi. The HER kinetics for porous film is processed by the Volmer–Heyrovsky reaction, whereas the fully dense counterpart is Volmer-limited. This study presents a clear comparison of HER behavior between porous and fully dense CuNi films.

Polycaprolactone (PCL) is one of the promising linear aliphatic polyesters which can be used as mulching film. Although it has suitable glass transition temperature and good biodegradability, further practical applications are restricted by the limited temperature-increasing and moisturizing properties. The rational design of the PCL structure is a good strategy to enhance the related properties. In this study, thermally-induced phase separation (TIPS) was introduced to fabricate a PCL nanoporous thin film. The introduction of a nanoporous structure on the PCL surface (np-PCL) exhibited enhanced temperature-increasing and moisturizing properties when used as mulch film. In detail, the average soil temperature of np-PCL was increased to 17.81 °C, when compared with common PCL of 17.42 °C and PBAT of 17.50 °C, and approaches to PE of 18.02 °C. In terms of water vapor transmission rate, the value for np-PCL is 637 gm−2day−1, which was much less than the common PCL of 786 and PBAT of 890 gm−2day−1. As a result, the weed biomass under the np-PCL was suppressed to be 0.35 kg m−2, almost half of the common PCL and PBAT. In addition, the np-PCL shows good thermal stability with an onset decomposition temperature of 295 °C. The degradation mechanism and rate of the np-PCL in different pH environments were also studied to explore the influence of nanoporous structure. This work highlights the importance of the nanoporous structure in PCL to enhance the temperature-increasing and moisturizing properties of PCL-based biodegradable mulching film.

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Abstract For efficient electrolysis of water for hydrogen generation or other value-added chemicals, it is highly relevant to develop low-temperature synthesis of low-cost and high-efficiency metal sulfide electrocatalysts on a large scale. Herein, we construct a new core–branch array and binder-free electrode by growing Ni3S2 nanoflake branches on an atomic-layer-deposited (ALD) TiO2 skeleton. Through induced growth on the ALD-TiO2 backbone, cross-linked Ni3S2 nanoflake branches with exposed {$$\bar{2}10$$ 2¯10 } high-index facets are uniformly anchored to the preformed TiO2 core forming an integrated electrocatalyst. Such a core–branch array structure possesses large active surface area, uniform porous structure, and rich active sites of the exposed {$$\bar{2}10$$ 2¯10 } high-index facet in the Ni3S2 nanoflake. Accordingly, the TiO2@Ni3S2 core/branch arrays exhibit remarkable electrocatalytic activities in an alkaline medium, with lower overpotentials for both oxygen evolution reaction (220 mV at 10 mA cm−2) and hydrogen evolution reaction (112 mV at 10 mA cm−2), which are better than those of other Ni3S2 counterparts. Stable overall water splitting based on this bifunctional electrolyzer is also demonstrated.

Two-dimensional MXenes with their outstanding physical and chemical properties have been extensively used in numerous fields such as electrochemical energy storage, catalysis, and sensing. In these applications, high active surface area and facilitated diffusion of ions/atoms/molecules are crucial. While these features can be offered by porous films and structures, their fabrication at ambient conditions, especially with scalable methods such as printing and coating has proven to be quite challenging. Here, we have developed MXene inks containing a space-holder agent, based on which porous films with tunable porosities can be easily coated. The whole fabrication process lasts only a few minutes and is carried out at room temperature and pressure, making it suitable for continuous scalable production. Films with different porosities (up to 80%) have been coated and used for the fabrication of solid-state microsupercapacitors with enhanced rate capability and improved capacitance (241 mF/cm²). [ABSTRACT FROM AUTHOR]

The Lead halide perovskite nanoparticles are a promising color conversion material for display application. The polarized emission from perovskite color enhancement films can boost LCD efficiency. In this article, we propose a method to induce the polarized emission from isotropic perovskite nano‐cubes, using a stretched porous polymer film. Optical simulation is performed to optimize the system design. The polarized perovskite color enhancement film can bring the optical efficiency improvement of 16.8% is expected for LCDs. Furthermore, the porous film offers good stabilization for the perovskite nanoparticles making it feasible for reliable device application. [ABSTRACT FROM AUTHOR]

In this study, we developed a polystyrene-platinum/nitrogen-doped titanium dioxide/strontium titanate composite-polyvinylpyrrolidone (PS-PNS-PVP) photocatalyst film, which is applied in the process of photocatalytic hydrolysis under simulated sunlight to produce hydrogen, is developed. PS, which is cheap, non-toxic, with high UV resistance, and chemical inertness, is used as a carrier, and a highly effective hydrogen production of Pt/N–TiO 2 /SrTiO 3 as a photocatalyst. The influence of the PS concentration on the stability, optical, and electrical properties of the photocatalyst film is discussed. In addition, the influence of the photocatalyst dispersion in the film on the activity under various photocatalyst concentrations was investigated. A polyvinylpyrrolidone pore-forming agent was then used to examine the effect on the photocatalyst film structure and optical properties, and the subsequent influence on photocatalytic hydrogen energy activity. Adjusting the PS concentration to 20 wt% produced good film-forming stability, and the photocatalyst dispersibility in the film under different photocatalyst concentrations. A photocatalyst concentration of 2.5 wt% resulted in good film dispersibility and the realization of added pore-forming agent. The modified photocatalyst film changed the film from a blind pore structure to a connecting void structure, increasing the film's porosity and hydrophilicity. This increased the number of photocatalytic sites, and the optimal hydrogen production of the photocatalyst film reached 21,333 μmol h−1 g−1. [Display omitted] • Porous PS-PNS-PVP film with high hydrogen production was synthesized. • Optimal casting solution of PS-PNS film is 20%. • PS-PNS-PVP film performed good H 2 production owing to connecting hole structure. • The best H 2 production efficiency of PS-PNS-PVP film was 21,333 μmol h−1 g−1. [ABSTRACT FROM AUTHOR]

Developing cost-effective advanced carbon anode is critical for innovation of sodium ion batteries. Herein, we develop a powerful combined method for rational synthesis of free-standing binder-free carbon nanospheres arrays via chemical bath plus hydrothermal process. Impressively, carbon spheres with diameters of 150–250 nm are randomly interconnected with each other forming highly porous arrays. Positive advantages including large porosity, high surface and strong mechanical stability are combined in the carbon nanospheres arrays. The obtained carbon nanospheres arrays are tested as anode material for sodium ion batteries (SIBs) and deliver a high reversible capacity of 102 mAh g−1 and keep a capacity retention of 95% after 100 cycles at a current density of 0.25 A g−1 and good rate performance (65 mAh g−1 at a high current density of 2 A g−1). The good electrochemical performance is attributed to the stable porous nanosphere structure with fast ion/electron transfer characteristics.

There is usually a tough trade-off between the mechanical property and the shielding performance in electromagnetic interference shielding (EMI) materials, especially for those ultrathin and porous film-based devices. Herein, we report an ultrathin and flexible RGO/CNF@Ag–Fe3O4 (RGCF) porous film for EMI shielding application by a vacuum-assisted filtration method and a hydrazine-induced foaming process. The RGCF-3 porous film exhibits outstanding mechanical properties with a tensile strength of 175.5 MPa. As expected, the EMI shielding effectiveness of the lightweight RGCF-3 porous film (21.0 dB) is much higher than that of the compact film (10.4 dB), due to the improved efficient wave attenuation within the cellular space. Therefore, the flexible and lightweight RGCF porous film with applicable EMI shielding and superior mechanical strength is highly promising for applications in wearable electronics. [ABSTRACT FROM AUTHOR]

Ultraviolet photocatalytic oxidation (UV-PCO) is a promising gaseous volatile organic compounds (VOCs) elimination method, of which the PCO kinetics are closely related to the radiation and airflow (contaminants) fields. Mathematical models have been developed in extensive studies to demonstrate the PCO kinetic reactions. Computational fluid dynamics (CFD) simulation was also carried out to display the irradiance and flow fields in the reactor. However, it still lacks an in-depth understanding of the light and mass transfer within the porous film coating where the microscopic structures dominate. To close this gap, this paper concentrates on the development of mathematical models for describing the light propagation, mass transfer, and reaction kinetics within the porous film coating. Incorporated with a CFD model for solving the mass, momentum and energy conservation, the sophisticated PCO process in the reactor can be accurately reproduced. The developed models have been validated by the experimental data, and are comparable with other models in the literature. The developed numerical models provide the implications of mass transfer for film coating UV-PCO reactor design. [ABSTRACT FROM AUTHOR]

In this study, poly(vinyl alcohol)/platinum/nitrogen-doped titanium dioxide/strontium titanate composite (PVA/Pt/NT/STO) porous films with adjustable pore sizes were successfully synthesized using the facile etching SiO 2 method. This enhanced the light transmittance and contact rate between the photocatalyst and solution. The effects of the size and number of the pores on the hydrogen production rate were studied under simulated sunlight. The pore size of the PVA/Pt/NT/STO film increased with increasing particle size of the as-prepared SiO 2 , and the photocatalytic hydrogen production efficiency increased with increasing pore size and number. Due to the formation of pores on the film, the light transmittance and charge separation of the film increased. Owing to the good light transmittance and charge separation of the porous PVA/Pt/NT/STO film, the optimal photocatalytic hydrogen production rate of the PVA/Pt/NT/STO-8S-I-20 reached 34,895 μmol/h/g when the alcohol solvent, synthesis time, and SiO 2 concentration were isopropanol, 20 h, and 8 wt%, respectively. Furthermore, the photocatalytic hydrogen production rate was approximately three times higher than that of the dense PVA/Pt/NT/STO film. [ABSTRACT FROM AUTHOR]

A new hybrid post‐synthetic and in‐film encapsulation method of colloidal perovskite nanoparticles is disclosed. The stabilization of the encapsulated perovskites against oxygen and humidity is tested and discussed. The convenience and scalability of this method opens avenue for perovskites to display application. [ABSTRACT FROM AUTHOR]