Single-component Films Research Articles

Unveiling the emerging trends of egg components-based biodegradable food packaging development: A comprehensive review.

Food packaging plays a crucial role in the food supply chain by aiding in food preservation and reducing food losses throughout the distribution process. The extensive, unregulated utilization, and waste mismanagement of food packaging materials made up of conventional petroleum-based plastics has led to a significant environmental crisis. Egg components-based food packaging has attracted considerable attention from the global packaging industry as a viable alternative to synthetic polymers due to its biodegradability, sustainability, and health-related benefits. This comprehensive review explores the composition and properties of egg components (eggshell, eggshell membrane, egg white, and egg yolk), and recent advancements in biodegradable packaging films derived from them. Additionally, it introduces the characteristics of these films and their applications in food, highlighting their biodegradability, sustainability, and suitable mechanical, barrier, thermal, optical, antioxidant, and antimicrobial properties as substitutes for traditional synthetic polymers. The utilization of various egg components in the packaging industry is a safe, non-toxic, cost-effective, and economical approach. However, it was found that incorporating active compounds from natural sources into packaging films, as well as composite films composed of egg components combined with other biopolymers, resulted in superior properties, compared to single component films. Moreover, the application of novel technologies in film development has proven to be more effective than conventional methods. These innovative egg components-based packaging films can be optimized and commercialized for use as packaging materials for food products.

Interfacing poly(p-anisidine) with photosystem I for the fabrication of photoactive composite films.

Photosystem I (PSI) is an intrinsically photoactive multi-subunit protein that is found in higher order photosynthetic organisms. PSI is a promising candidate for renewable biohybrid energy applications due to its abundance in nature and its high quantum yield. To utilize PSI's light-responsive properties and to overcome its innate electrically insulating nature, the protein can be paired with a biologically compatible conducting polymer that carries charge at appropriate energy levels, allowing excited PSI electrons to travel within a composite network upon light excitation. Here, a substituted aniline, 4-methoxy-aniline (para-anisidine), is chemically oxidized to synthesize poly(p-anisidine) (PPA) and is interfaced with PSI for the fabrication of PSI-PPA composite films by drop casting. The resulting PPA polymer is characterized in terms of its structure, composition, thermal decomposition, spectroscopic response, morphology, and conductivity. Combining PPA with PSI yields composite films that exhibit photocurrent densities on the order of several μA cm-2 when tested with appropriate mediators in a 3-electrode setup. The composite films also display increased photocurrent output when compared to single-component films of the protein or PPA alone to reveal a synergistic combination of the film components. Tuning film thickness and PSI loading within the PSI-PPA films yields optimal photocurrents for the described system, with ∼2 wt% PSI and intermediate film thicknesses generating the highest photocurrents. More broadly, dilute PSI concentrations show significant importance in achieving high photocurrents in PSI-polymer films.

Bifunctional NiCoP/NiCo Electrocatalysts on Nickel Foam for Overall Water Spillting

AbstractNiCoP/NiCo composite electrocatalysis electrodes were successfully prepared using co‐electro‐deposition method followed by low temperature phosphorization process. The combination of the two transition metals and their phosphides is expected to provide more heterogeneous structures and hierarchical interfaces for the catalyst, promoting the synergistic effect in the electrocatalysis process. The influences of the transition NiCo alloy on the morphology and catalysis performance of the composite were studied. In comparison to single component films, a considerably higher electrochemical response was observed in hierarchically porous NiCoP. The composite NiCoP/NiCo/NF electrode exhibited superior electrocatalytic activity toward HER (with overpotential of 18 and 76 mV) and OER (with overpotential of 220 and 323 mV) in alkaline electrolyte, reaching current density of 10 and 100 mA cm−2, respectively. The NiCoP/NiCo/NF electrode can be used as the cathode or anode electrode for the electrolysis cells and endow them with high electrocatalytic performance and long term stability for water splitting.

Solution-processed transparent PVP:HfO2 hybrid dielectric films with low leakage current density and high k

Organicinorganic hybrid dielectric materials have attracted significant attention owing to their capacity to integrate the mechanical and electrical characteristics of organic and inorganic components. This paper presents the deposition of high-performance polyvinylpyrrolidone (PVP): hafnium oxide (HfO2) hybrid dielectric films at low temperature using the sol-gel method. Initially, the influence of precursor components on the surface morphology of single-component dielectric films was investigated. It is observed that the addition of FSO and acetic acid can result in smoother and more uniform surfaces for PVP and HfO2, respectively. Furthermore, based on these findings, we successfully prepared PVP:HfO2 hybrid dielectric films with surface roughness below 1 nm, high transmittance above 95% in the visible range (400–760 nm), and wide optical bandgaps exceeding 5.3 eV. The formation of PVP:HfO2 cross-linked network was identified through FTIR analysis, and a mechanism was proposed. Moreover, MIM devices were fabricated to determine the insulating performance of dielectric films. We found that the PVP:HfO2 hybrid dielectric films exhibit a significant reduction in leakage current density and a substantial increase in relative dielectric constant compared to the single-component dielectric films. In addition, with the increase in PVP concentration, the leakage current density first decreases and then increases, while the relative dielectric constant first increases and then decreases. After optimization, 0.5 wt% PVP:HfO2 hybrid dielectric film exhibits a low leakage current density of 5.89×10−8 A/cm2 @1 MV/cm and a high relative dielectric constant of 32.54. PVP:HfO2 hybrid dielectric films exhibit tremendous potential for applications in the realm of high-performance transparent electronic devices.

Facile fabrication of amorphous-In2Se3/Si heterojunction for fast ultraviolet to near-infrared broadband photodetection

Indium selenide (In2Se3) has emerged as a promising candidate for broadband photodetection due to its suitable bandgap, high electron mobility, high optical absorption coefficient, and broad-spectrum absorption properties. Nevertheless, wafer-scale growth of single-component and pure-phase In2Se3 films remains challenging and requires stringent experimental parameters. Here, a facile approach for depositing amorphous-In2Se3 (a-In2Se3) on Si substrate by physical vapor deposition (PVD) process is proposed to fabricate high-performance a-In2Se3/Si heterojunction photodetectors. The as-produced devices are sensitive to a broad-spectrum (255–1300 nm), exhibiting superior overall performance with a low dark current of 0.54 nA, large current on/off ratio of 2.26 × 104, fast response with rise/decay time of 176/175 μs, decent responsivity of 1.50 A/W and detectivity of 6.46 × 1012 Jones under 1050 nm illumination at − 3 V bias. Such remarkable results can be attributed to the unique type-Ⅰ straddling energy band alignment and the strong coupling between a-In2Se3 and Si interface. In addition, decent responsivity and detectivity under 255 nm (0.29 A/W and 1.25 × 1012 Jones) and 630 nm (0.77 A/W and 3.32 × 1012 Jones) remedy the deficiency of Si in ultra-violet and visible light detection. Our work provides a facile and low-cost route for the realization of high-performance broadband photodetectors based on a-In2Se3/Si heterojunctions.

Surface Modification of Biomedical Ti-18Zr-15Nb Alloy by Atomic Layer Deposition and Ag Nanoparticles Decoration.

Superelastic biocompatible alloys attract significant attention as novel materials for bone tissue replacement. These alloys are often composed of three or more components that lead to the formation of complex oxide films on their surfaces. For practical use, it is desirable to have a single-component oxide film with a controlled thickness on the surface of biocompatible material. Herein we investigate the applicability of the atomic layer deposition (ALD) technique for surface modification of Ti-18Zr-15Nb alloy with TiO2 oxide. It was found that a 10-15 nm thick, low-crystalline TiO2 oxide layer is formed by ALD method over the natural oxide film (~5 nm) of the Ti-18Zr-15Nb alloy. This surface consists of TiO2 exclusively without any additions of Zr or Nb oxides/suboxides. Further, the obtained coating is modified by Ag nanoparticles (NPs) with a surface concentration up to 1.6% in order to increase the material's antibacterial activity. The resulting surface exhibits enhanced antibacterial activity with an inhibition rate of more than 75% against E. coli bacteria.

Spin Coating Photoactive Photosystem I–PEDOT:PSS Composite Films

Photosystem I (PSI), a naturally abundant multi-subunit protein complex known for its ability to harvest solar energy and transform it into chemical energy in photosynthesis, is mixed with an intrinsically conducting polymer (ICP) poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) to deposit well-mixed thin films via spin coating from aqueous solution. This process enables uniform, reproducible, and rapid film formation in which the composition and thickness of composite films can be readily tuned up to a few hundred nanometers. We assess the size distributions of the system in solution as well as the composition, thickness, conductivity, scalability, and photoactivity of the resulting biohybrid PSI–polymer films. The combination of the protein and ICP yields increased photocurrents and turnover numbers when compared to single-component films of the protein or ICP alone to reveal a synergistic combination of film components. Based on photocurrents and turnover numbers, the efficiency of integrating the protein with the polymer is highest at low PSI loadings where protein–polymer interactions are maximized.

Effects of processing parameters on the morphologies of complex sesquioxide thin films

Controlling and predicting the morphology of lanthanide sesquioxides in thin film form is vital to their use in current applications. In the present study, single and codeposited Sm2O3, Er2O3, and Lu2O3 thin films were grown on yttria-stabilized zirconia (8%) substrates by radio frequency magnetron sputtering at room temperature and 500 °C. The effect of two different substrate temperatures and altering the oxide cation on the structural and morphological properties of the films was analyzed. The thin films were characterized by profilometry, scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. The single-component Lu2O3 and Sm2O3 films obtained were of the cubic phase, and the Er2O3 was a mix of cubic and monoclinic phases. It was observed for both the Er2O3 and Lu2O3 films that increasing the substrate temperature to 500 °C resulted in larger grained polycrystalline films. In contrast, large grained polycrystalline films were obtained at both room temperature and 500 °C for Sm2O3 and uneven granularity increased as temperature increased. Codeposition of Lu2O3 and Sm2O3, and Lu2O3 and Er2O3 resulted in a cubic bixbyite phase (the C phase of the lanthanide sesquioxide) solid solution. It was observed that the structure and morphology of the films can be controlled by manipulating deposition parameters. Both substrate temperature and altering the oxide cation contributed to changes in crystallinity and grain structure, which can modify the chemical and physical properties of the films for their applications.

Đánh giá khả năng chống ăn mòn của màng (Ti, Cr)N được chế tạo bằng phương pháp hồ quang cathod (arc-PVD) trên nền thép SS304

The monolayer (TiN/Ti), multilayer single-component (Ti/TiN; Ti/CrN) and multilayer multicomponent (Ti/TiN/CrN; Ti/CrN/TiN) films were deposited on SS304 steel by cathodic arc deposition method with an average thickness of 2300 nm. Research results showed that many macro particles (peaks) and holes (valleys) appeared and evenly distributed on the surface, the monolayer film had better quality (Ra = 0,08-0,1 µm) than the multilayer film (Ra = 0,1÷0,2 µm), but the adhesion to the substrate was poor. X-ray diffraction spectroscopy recorded the preferred orientation (111) with monolayer films and switched to (200) with multilayer films. The corrosion potential and current of the fabricated films were both reduced compared to the SS304, but in the multilayer films, the expansion of the passive regions was recorded: -0,2÷0,6 V (Ti/TiN/CrN Ti/CrN/TiN) and -0,2÷0,2 V (TiN/Ti, CrN/Ti).

Patterning alternate TiO2 and Cu2O strips on a conductive substrate as film photocatalyst for Z-scheme photocatalytic water splitting

Semiconductor heterostructures mediated by electrical conductors are very promising for Z-scheme photocatalytic water splitting. In contrast to conventional particulate heterostructures, alternate TiO2 and Cu2O film stripes patterned parallel on a fluorine-doped tin oxide (FTO) conductive substrate was fabricated as a model film photocatalyst to study the characteristics of the photogenerated charge transfer process. The Z-scheme transfer process with an effective transport distance of up to 5 μm occurs only in regions distant from the TiO2/Cu2O strip edges through the FTO substrate from the bottom. In contrast, the transfer of charge around their contact regions follows the conventional transfer process through the TiO2/Cu2O strip interface. These results indicate that the Z-scheme transfer process occurring in such a large region dominates the charge transfer processes in the TiO2/FTO/Cu2O pattern film heterostructure. Importantly, unlike the single component film, which is inactive for photocatalytic overall water splitting, the modified TiO2/Cu2O pattern film can induce photocatalytic overall water splitting at a stoichiometric H2/O2 ratio close to 2:1. These findings have significant implications in designing efficient heterostructures by employing a Z-scheme charge transfer process.

Improved methods for design of PLD and combinatorial PLD films

Pulsed laser deposition (PLD) is a powerful technique for prototyping thin film materials, both single component (single composition) films and films with a varying composition (e.g., lateral continuous compositional spread, CCS). In this work, we improve one of the simulation methods used to design the deposition of PLD films: We extend the mathematical model for the material spread on the substrate, T1(x,y), for each laser pulse hitting the target, and we use a more accurate method to determine T1(x,y) experimentally. The deposition of the material on the substrate is simulated by repetitively adding T1(x,y), from one or more targets, at the selected location on the substrate. Using the new model, a high agreement between the simulated and grown films’ thickness and composition across the substrate was obtained. The basis for the high agreement is the use of variable angle spectroscopic ellipsometry to carefully determine T1(x,y) by measuring at 794 locations on the 50.8 mm (2 in.) diameter substrates. Factors, such as variation in optical properties and porosity across the plume/calibration films, were considered in the determination of the thicknesses. As test cases, we simulated and deposited (single component) TiO2 thin films and (CCS) TiO2 films doped with Cr and N, deposited on 50.8 mm diameter Si wafers. The modeling and simulations are implemented in an open-source Python library, pyPLD.

Preparation of iron porphyrin/calix[8]arene/graphene ternary composites based on molecular recognition function and their dopamine electrochemical sensing properties

<p indent="0mm">In this paper, tetrabiphenylporphyrin iron (FeTBPP) with electrocatalytic activity and <italic>p</italic>-<italic>tert</italic>-butyl calix[8]arene (C[8]A) with specific molecular recognition functions were self-assembled onto highly conductive graphene oxide (GO) by interfacial self-assembled method to obtain FeTBPP/C[8]A/GO composite film. The structural characterization for the composite film showed that the FeTBPP grew on the conjugated plane of GO by π-π interaction, while C[8]A molecules combined with GO by the hydrogen bond. These ensure good dispersion of the two kinds of molecules on the GO template. Compared with the single component films of the two kinds of molecules, the composite films have significantly improved surface morphology and higher conductivity. The electrochemical test showed that the response current is linear with dopamine (DA) concentration, with a wide detection range of 0.1–1000 μM, high sensitivity of 17.6 μA/mmol and LOD of 25.6 nM. More importantly, depending on the anchoring and dispersing effects of GO on FeTBPP and C[8]A, the detection of DA by composite electrode has high stability, reproducibility and selectivity. The sensor was applied to human urine and serum samples, and the highly sensitive detection of DA was successfully realized.

Heteroepitaxial Growth of Colloidal Crystals: Dependence of the Growth Mode on the Interparticle Interactions and Lattice Spacing.

Epitaxial growth is one of the most important techniques for the control of crystal growth, especially for growing thin-film semiconductor crystals. Similarly, colloidal epitaxy, a template-assisted self-assembly method, is a powerful technique for controlling the structure of colloidal crystals. In this study, heteroepitaxial growth, which differs from homoepitaxial growth of conventional colloidal epitaxy, using foreign colloidal crystals as a substrate, was used to grow single-component colloidal crystal films. The Frank-van der Merwe (FM), Stranski-Krastanov (SK), and Volmer-Weber (VW) modes were observed, and the mode varied with the lattice-misfit ratio and interparticle interactions between the substrate and epitaxial phase. The transition of the growth mode (from SK to VW) and the coexistence of different growth modes (FM and VW) were observed, and their processes were revealed by in situ observation. Colloidal heteroepitaxy was confirmed to be useful for controlling structure, which will enable exploration of novel colloidal self-assembly structures.

Electrical properties of antiferroelectric Pb(Zr,Hf)O3 films fabricated by chemical solution deposition

Pb(Zr1−x Hf x )O3 (x = 0, 0.1, 0.2, 0.5, 1) films were fabricated on Pt/Ti/SiO2/Si substrates using a chemical solution deposition process in this study. The effect of the Zr/Hf ratio on energy-storage performance was evaluated based on the measurement of P–E hysteresis loops. It is shown that the maximum polarization and the recoverable energy density decrease with the increase of the Hf concentration. The energy efficiency of the Hf-contained films is close to each other but higher than the PbZrO3 film. As a result, the Pb(Zr0.9Hf0.1)O3 film achieved in this work exhibited the highest recoverable energy density of 11.3 J cm−3 and a larger energy efficiency of 55% at 800 kV cm−1, exceeding those of either PbZrO3 or PbHfO3 single-component film. This enhancement was related with the size and homogeneity of the crystal grains.

Electrotuneable Radical Polymers for Thin-Film Electronic Device Applications

Polyradicals, organic polymers in which each repeating sub-unit contains a stable radical with an unpaired spin, are establishing themselves as unique alternatives to state-of-the-art conducting polymers for a variety of applications. A decisive advantage of polyradicals rests on their charge tunability and switchable transport properties. Current interests in polyradicals have been focused on batteries and resistive memory devices. Polyradical doping has remained a challenge, however, notwithstanding recent developments. Due to doping issues, single-component polyradical organic field-effect transistors (OFETs), a vital milestone in polyradical electronics, have not yet been achieved. Here, we demonstrate that an OFET architecture with source-drain contacts sandwiching the polyradical active layer led to on/off ratios >103 in what are the first p-type polyradical-FETs (PR-FETs) reported so far. These OFETs are based on a 6-oxoverdazyl polyradical with no impurity doping, in which hole injection occurs due to tunable charge states at the polyradical/source interface. By introducing the new concept of contact-doping, our work provides a route for translating single-component polyradical thin films into OFETs, the fundamental building blocks of organic electronics. Because of the switchable transport properties of 6-oxoverdazyl polyradicals, our PR-FETs could be used to implement the first organic mem-transistors reported to date.

Programmable Humidity-Responsive Actuation of Polymer Films Enabled by Combining Shape Memory Property and Surface-Tunable Hygroscopicity.

Most humidity-responsive polymeric actuators can only exhibit shape transformations between a planar shape in the dry state and a bended three-dimensional (3D) shape when exposed to moisture, and it is challenging to design and prepare hygroscopic actuators with programmable actuating behaviors displayed from sophisticated 3D structures. Herein, we demonstrate that the integration of shape memory property and surface treatment enabled hygromorphic responsivity endows a single-component polymer film with programmable moisture-driven actuating behaviors. The solvent-processed polyethylene-co-acrylic acid (EAA) copolymer film is soft and stretchable at room temperature, and has a good thermal-responsive shape memory property. By surface treatment using base/acid solutions, the reversible gradient conversion between carboxyl groups and carboxylate salts along the thickness direction enables the film to exhibit designed hygroscopic actuations. The shape memory property and moisture-driven actuating behaviors can be combined to realize 3D-3D morphing by first programming the films into 3D shapes and then conducting the surface treatments. Both shape programming and surface treatment processes can be reprogrammed to make the actuation behavior readily tunable. We also show that the created surface patterns can act as moisture-sensitive conducting paths to detect human breathes, and the combination of shape memory, moisture-responsive morphing and conductivity change leads to some interesting applications such as smart switch in conducting circuit. This work provides a new and general strategy for the design of advanced humidity-responsive actuators.

Mechanical Robust Flexible Single-Component Organic Solar Cells.

Owing to the advantages of being lightweight and compatible with surfaces with different deformations, flexible organic solar cells (OSCs) have broad scopes of applications, including wearable electronics and portable devices. Most flexible OSCs focus on the two-component bulk-heterojunction (BHJ) photo-active layers, but they usually suffer from degradation problems both in efficiency and mechanical durability derived from the limited phase stability under mechanical and thermal stress. Whereas, single-component organic solar cells (SCOSCs) based on the double-cable conjugated polymer are supposed to possess excellent mechanical robustness and long-term stability. Here, the first flexible SCOSCs based on a double-cable polymer are fabricated on a transparent silver nanowires (AgNWs) electrode on a plastic foil. Impressively, the obtained flexible SCOSCs exhibited a power conversion efficiency (PCE) of 7.21%. The flexible SCOSCs are further demonstrated to possess superior mechanical robustness (>95% retention after 1000 bending cycles) and storage stability (>97% retention after 430 h in nitrogen atmosphere) compared to several BHJ-type flexible OSCs. The pseudo-free-standing tensile test and morphology investigation are conducted to reveal the distinction in mechanical durability of the single-component polymer film and the BHJ-type films. Besides, ultraflexible SCOSCs are also fabricated, indicating the application prospect and superiority in flexible devices and wearable electronic products.

Fibre-based composites from the integration of metal–organic frameworks and polymers

The integration of metal–organic frameworks (MOFs) with polymer fibres enables the formation of fibrous composite materials with advantages over traditional single-component polymer films and mixed-matrix membranes. In comparison with mixed-matrix membranes, MOF–polymer fibrous composites offer improved molecular transport through the material and easier access to the active sites of MOFs. These attributes make fibrous composites appealing for clothing, personal protective equipment, air purification and filtration, biomedical equipment and delivery of therapeutics, along with detection and sensing applications. In this Review, we outline approaches for the incorporation of MOFs into, or onto, polymer fibres and present some applications for MOF–polymer fabrics. The integration of MOFs and polymers can either occur prior to fibre formation (namely, MOF-first), via particle deposition (resulting in either covalent or non-covalent attachment) of MOFs to the fibre or by in situ MOF growth after fibre formation (namely, fibre-first). We focus on the structure–processing–activity relationships — for example, MOF loading, MOF crystal size, polymer concentration and processing parameters — that impact the behaviour of fibrous composites. We conclude with a discussion of research avenues that can advance this burgeoning field. Composites made from metal–organic frameworks and polymer fibres are gaining popularity in many applications because of their tailorable morphologies and properties. This Review summarizes various methods for fabricating these composites, explores structure–processing–activity relationships and discusses future research opportunities.

Composite films of graphene oxide with semiconducting carbon nanotubes: Raman spectroscopy characterization

Noncovalent interaction between semiconducting single-walled carbon nanotubes (SWNTs) and graphene oxide (GO) in composite films (GO-SWNTs) was analyzed by Raman spectroscopy in the range of D and G modes (1170–1780 cm−1). Comparison between Raman spectra of composite film and single-component GO and SWNTs films showed that the interaction between GO and SWNTs is accompanied by a band broadening and spectral shifting. Observed spectral transformations are attributed to charge transfer between GO and SWNTs as well as a deformation of carbon surfaces which occurs in the composite. Spectral measurements of composite GO-SWNTs film with biological globular molecules (the enzyme glucoseoxidase) showed that these molecules weaken mechanical stress of GO on the nanotubes.

Electron-Induced Modification of Self-Assembled Monolayers of Aromatic Carboxylic Acids

The effects of low-energy electrons on aromatic self-assembled monolayers (SAMs) with carboxylic acid (CA) docking groups were studied with a focus on the dose range below 5 mC/cm2. The SAMs were prepared on an underpotentially deposited Ag bilayer and comprised nonsubstituted and CA-substituted monolayers with a rod-like biphenyl backbone and a monolayer of a Y-shaped, CA-substituted molecule, 1,3,5-benzenetribenzoic acid (H3BTB), formed either as a single-component film or as a binary one by mixing with adamantane-CA (Ad-CA). X-ray photoelectron and near-edge X-ray absorption fine structure spectra suggest high proneness of the CA groups to electron irradiation at both SAM/substrate and SAM/ambient interfaces. Cleavage of the carboxylate-substrate bond results in substantial molecular desorption at the initial stage of irradiation until electron-induced cross-linking gradually takes over. The CA groups at the outer SAM interface undergo substantial chemical changes, indicating that they participate in the cross-linking chemistry. The electron-induced processes are accompanied by molecular reorientation. Disordering for the SAMs formed by the rod-like molecules is contrasted by the H3BTB-based systems where changes also occur but some molecular order is preserved as explained by a proposed model invoking conformational changes. In SAMs of H3BTB mixed with Ad-CA, the latter shows higher proneness to irradiation-induced desorption than the former, as well as an influence on the cross-linking chemistry. The results of the present study suggest that CA-based SAMs on Ag offer additional options for cross-linking in SAMs and, as exemplarily demonstrated by the generation of Cu patterns on structured H3BTB templates, can be efficiently used for lithography and nanofabrication.