Complex Films Research Articles

ON OBTAINING BINARY POLYELECTROLYTE COMPLEXES OF CHITOSAN BOMBYX MORI WITH COLLAGEN

We obtained binary polyelectrolyte complexes containing chitosan from Bombyx mori and collagen with a mass ratio of 10:1; 10:2, and 10:3. During the interaction between the macromolecules, due to the compensation of the positive charges of chitosan with the negative charges of collagen, the zeta potential of the solutions of polyelectrolyte complexes changed from +15.2 to +5.67 mV. We revealed the dependence of the size characteristics of the particles of polyelectrolyte complexes on time and the ratio of macromolecules. An examination of the morphology of the films of polyelectrolyte complexes demonstrated that in the evaluated chitosan/collagen mass ratios, non-spherical nanosized particles up to ≤ 60 nm form on the surface of the films. We evaluated the mechanism of formation of complexes by using Fourier-transform infrared spectroscopy and confirmed the findings with density functional theory and molecular dynamics. We found that the particle diameter is inversely proportional to the diffusion coefficient. The results show that the particles are almost uniformly distributed over the surface of the polymer matrix and have a unimodal character. We obtained reproducible results when using a chitosan/collagen mass ratio of 10:2 to dye natural silk. We found that the complexes contribute to increase the intensity and stability of colour relative to soap and friction.

Neuron Contact Detection Based on Pipette Precise Positioning for Robotic Brain-Slice Patch Clamps.

A patch clamp is the "gold standard" method for studying ion-channel biophysics and pharmacology. Due to the complexity of the operation and the heavy reliance on experimenter experience, more and more researchers are focusing on patch-clamp automation. The existing automated patch-clamp system focuses on the process of completing the experiment; the detection method in each step is relatively simple, and the robustness of the complex brain film environment is lacking, which will increase the detection error in the microscopic environment, affecting the success rate of the automated patch clamp. To address these problems, we propose a method that is suitable for the contact between pipette tips and neuronal cells in automated patch-clamp systems. It mainly includes two key steps: precise positioning of pipettes and contact judgment. First, to obtain the precise coordinates of the tip of the pipette, we use the Mixture of Gaussian (MOG) algorithm for motion detection to focus on the tip area under the microscope. We use the object detection model to eliminate the encirclement frame of the pipette tip to reduce the influence of different shaped tips, and then use the sweeping line algorithm to accurately locate the pipette tip. We also use the object detection model to obtain a three-dimensional bounding frame of neuronal cells. When the microscope focuses on the maximum plane of the cell, which is the height in the middle of the enclosing frame, we detect the focus of the tip of the pipette to determine whether the contact between the tip and the cell is successful, because the cell and the pipette will be at the same height at this time. We propose a multitasking network CU-net that can judge the focus of pipette tips in complex contexts. Finally, we design an automated contact sensing process in combination with resistance constraints and apply it to our automated patch-clamp system. The experimental results show that our method can increase the success rate of pipette contact with cells in patch-clamp experiments.

Improving the Corrosion Resistance of Al anode and Specific Capacity in Al-air Batteries Using Mixed Electrolyte Solutions

This research aimed to investigate the corrosion improvement in Al-air batteries and their specific capacity, at various mixed ratios of sodium chloride and sodium hydroxide solutions 100:1, 99:1, 98:2, 90:10, 80:20, 70:30, and 0:100. The battery was discharged at different discharge current densities of 1, 5, 10, and 15 mA·cm-2. The self-corrosion of Al anodes and their electrochemical behavior was tested in the mixed electrolyte solutions at room temperature. Moreover, the chemical characterization of the electrode surface was analyzed using the EDS and XPS technique showing that mixed electrolyte solutions provide complex film on the aluminum surface, consisting of various atoms of Al, O, C, Na, and Cl which can reduce the self-corrosion of the aluminum anodes, and providing a higher energy capacity. Mixed electrolyte solutions with a sodium chloride to sodium hydroxide ratio of 80:20 by volume at a discharge current of 15 mA·cm-2 causes a maximum specific capacity of 1,508 mA·h·g-1. The mixed electrolyte solutions can increase the specific capacities of Al-air batteries by 1.4 and 25.6 times more than that of sodium chloride solution and sodium hydroxide solution alone, respectively.

Application of Ag/Tannic acid-FeIII nanocomposite as multifunctional bacteriostatic to enhance the performance of chitosan/gelatin/polyvinyl alcohol complex films

As the demand for food quality and safety continues to rise, antimicrobial active packaging materials with good mechanical and barrier properties have received urgent attention from the food industry. In this study, three types of Ag/tannic acid-FeIII ion nanocomposites (TFA) were synthesized using an in-situ method and incorporated into a chitosan/gelatin/polyvinyl alcohol complex film (CF) to produce multifunctional and highly cross-linked active films. The impact of TFA prepared through three different methods on the microstructure and functional properties of the CF were investigated. The structure of the TFA-loaded films was investigated to confirm the strong intermolecular interactions between the polymers and TFA. The TFA established multidimensional physical interactions and cross-linked the polymers, thereby enhancing the mechanical properties of the CF and providing excellent antioxidant activity and photothermal effects. Under 808 nm near-infrared laser irradiation, the TFA-loaded films displayed potent antibacterial performance against both S. aureus and E. coli bacteria. This study demonstrated that the nanocomposite prepared via ascorbic acid reduction (TFAV) given the highest comprehensive performance rating to the film. It can be utilized not only for conventional food packaging but also as a continuous sterilization strategy for meat products storage due to its photothermal antibacterial functionality.

Synergistic effect of two metal porphyrins in a polymer catalyst for oxygen electroreduction

This work considers the formation and catalytic properties of films of individual hydroxyphenyl porphyrin complexes with manganese (manganese(III) acetate 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (MnAc(4-OHPh)P)) and iron (iron(III) chloride 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (FeCl(4-OHPh)P)) and their composites. The films of individual metalloporphyrins and bimetallic composites were obtained by superoxide-assisted electrochemical deposition in dimethylsulfoxide solutions. The formation of the bimetallic (Mn + Fe) porphyrin composite was confirmed by spectral methods. An analysis of the atomic-force microscopy results showed that the composite films consisted of larger globules and were rougher than those of individual porphyrins. The electroactive surface areas of the individual porphyrin films and the composite were significantly different from each other. The mechanism and kinetics of the oxygen electroreduction reaction (ORR) on the films of individual porphyrins and bimetallic composite were evaluated using a rotating disk electrode. The kinetic current density of the Tafel slope and the position of the ORR current wave on the surface of the poly-(MnAc(4-OHPh)P + FeCl(4-OHPh)P) composite indicate smaller kinetic limitations and lower overvoltage on this material than on carbositall and films of individual porphyrins. The smaller kinetic limitations and better energy characteristics can be explained by the synergistic effect produced by the combined action of the Mn- and Fe- catalytically active centers during ORR on the composite film.

Double-bounded diphenyl-contained fluorene polymers for Sc-SWCNTs composite to ammonia gas sensors: Diphenylethene or diphenylmethanimine

Semiconductor-type carbon nanotubes, renowned for their exceptional optoelectronic properties, are considered as the most promising candidates to replace conventional silicon-based semiconductors. However, the obtaining high purity of semiconductor-type single-walled carbon nanotubes (sc-SWCNTs) is a challenging task. In this study, the Suzuki coupling reaction was employed to synthesize two structurally similar alternating copolymers, which effectively separated the sc-SWCNTs from commercially plasma single-walled carbon nanotubes. As result, the copolymers exhibited outstanding selectivity for sc-SWCNTs with 99.9% of purity. Generation of a complex film at the surface. Employing these polymer/sc-SWCNTs composite materials, the ammonia gas sensing devices were fabricated. The results showed that both devices demonstrated rapid and exceptional response towards ammonia gas vapor. Test results revealed that when the ammonia gas vapor concentration of 20 ppm, the two polymer/sc-SWCNTs-based sensors exhibited response values of 5.0% and 3.3%, respectively, and the calculated limits of detection (LOD) of the sensors were 64.5 ppb and 53.5 ppb. These sensors demonstrated significant advantages in response and selectivity towards ammonia gas vapor compared to previous studies.

Polyacrylic acid (PAA)/Zn2+ complex films fabricated on steel substrate via one-step assembly for corrosion protection

Polyacrylic acid (PAA)/Zn2+ complex films fabricated on steel substrate via one-step assembly for corrosion protection

Triggering ZT to 0.32 in metal-organic complex films using n-doping modulation strategy

Triggering ZT to 0.32 in metal-organic complex films using n-doping modulation strategy

Structural and Magnetic Properties of a Drop-Cast C54H34Br4CuO4 β-Diketonato Complex Film on a Graphite Surface.

The structural and magnetic properties of a drop-cast film of flat C54H34Br4CuO4, a β-diketonato complex functionalized with bromine atoms, on a graphite surface are investigated using scanning tunneling microscopy, synchrotron X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. Experimental measurements reveal that the Cu-complexes preferentially lay flat on the graphite surface. The magnetic hysteresis loops show that the organic thin film remains paramagnetic at 2 K with an easy axis of magnetization perpendicular to the graphite surface and is therefore perpendicular to the plane of the Cu-complex skeleton.

Rational CoP/C complex film as high-reliable anode for lithium storage, from polyols regulated growth of graphene-like Co alkoxide

Rational cobalt phosphide/carbon (CoP/C) complex film composed of densely assembled CoP-in-carbon nanosheets was successfully constructed via filtration-induced self-assembly and in-situ transformation strategy. The successful implementation of this method relies on the morphology controlled preparation of graphene-like Co alkoxide by varying the chain length of polyols to regulate the polycondensation process. The graphene-like CoP-in-carbon construction units can accelerate ions/electrons transportation and guarantee structural robustness. Thanks to its ideal composite structure, CoP/C complex film exhibits outstanding cycling and rate performances, including high capacities up to 920.5 mAh g−1 over 200 cycles at 1 A g−1 and 826.5/662.3 mAh g−1 after cycling under 2/4 A g−1 over 1000 cycles. Besides, full-cells constructed with CoP/C complex film anodes and LiCoO2 cathodes exhibit superior cycling stability and reliable capacities of 773.4/518.7 mAh g−1 after 200 cycles at high rates of 1/4 A g−1. Such efficient and reliable strategy can offer new insights and understanding about the construction of advanced film materials for energy-storage devices.

Effect of blending ratio on the compatibility and stability of konjac glucomannan/starch composite systems

A series of complex dispersions and films combining Konjac glucomannan (KGM) and starch in different ratios were prepared. The compatibility and stability of KGM/Starch composite (KS) systems were evaluated using a new horizontal casting device coupled with CCD camera system and Near-infrared (NIR) spectrometer and multiple conventional characterization techniques. The findings from the casting device revealed that when the KGM and starch were combined in a 7∶3 ratio, the dispersion demonstrated isotropic behavior, flowing and diffusing at a consistent speed from the central point to the surrounding area on the casting disc. Additionally, the scattered particles in the NIR reflectance spectrum were evenly distributed at every point, indicating excellent compatibility and uniformity within the dispersion. FTIR and XRD analyses indicated the existence of molecular interactions between the film components, and showed good compatibility between KGM and starch when the KGM content was greater than 50%. The best compatibility was obtained when the KGM content was 70%. The SEM results showed that the increase of KGM content contributed to a smoother and denser microstructure in the cross-section of the KS composite films, especially when the KGM content was 70% (w/w). The rheological results of the KS dispersion further confirmed the formation of a hybrid network structure between KGM and starch. Higher KGM content led to more hydrogen bonds and provided more opportunities for macromolecular chain entanglement. This work will contribute to a better understanding of the interaction mechanism between polysaccharides and starch, as well as provide a new perspective and novel characterization methods to deconstruct the compatibility and assembly structure stability between KGM and starch. It is beneficial for facilitate the application of KGM in the development of denatured food or starch materials, including food texture properties and emulsion stability, and establish a foundation for the diversification of food design tools.

Principal Component Analysis (PCA) unravels spectral components present in XPS spectra of complex oxide films on iron foil

Principal component analysis (PCA), as applied to the processing of the complex X-ray photoelectron spectroscopy (XPS) lineshapes, is discussed. PCA analysis example is provided of complex native iron oxide films on Fe foil XPS spectra further modified by argon and helium ion beams. Abstract PCA components are derived from Fe 2p, O 1 s and C 1 s regions leading to the assignments of surface (oxy)hydroxide, Fe2O3, FeO and Fe metal, as corroborated by the corresponding elemental quantification profiles. Detailed mathematical concepts behind PCA analysis of spectra data are provided.

Excellent performance of 8-hydroxyquinoline and alkyl polyglycolides hybrid electrolyte additives on aluminum-air battery

We examine 8-hydroxyquinoline (8-HQ) and decyl glucoside (DG) as hybrid additives to inhibit the corrosion of Al-5052 anode in sodium hydroxide solution. The gas evolution experiment, electrochemical measurements, morphological and spectral analysis, ellipsometer, as well as simulating computation are used to investigate the corrosion inhibition strengthening mechanism. It demonstrates that 8-HQ can coordinate with Al3+ ions to form complex film. DG can assemble on the complex film to improve the corrosion inhibition performance through “micelle solubilization”. The optimum corrosion protection efficiency is 83.7% for 10 mM 8-HQ + 3 mM DG.

Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures.

Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, vertically aligned nanostructure (VAN) films using a self-assembling bottom-up deposition method presents great promise in terms of structural flexibility and property tunability. Here, the bottom-up self-assembly is extended to a new approach using a mixture containing a 2Dlayer-by-layer film growth, followed by a 3D VAN film growth. In this work, the two-phase nanocomposite thin films are based on LaAlO3 :LaBO3 , grown on a lattice-mismatched SrTiO3001 (001) single crystal.The 2D-to-3D transient structural assembly is primarily controlled by the composition ratio, leading to the coexistence of multiple interfacial properties, 2D electron gas, and magnetic anisotropy. This approach provides multidimensional film heterostructures which enrich the emergent phenomena for multifunctional applications.

Tannic acid complex encapsulation high load nano-silica self-healing coating for protection of stainless steel

Benzotriazole (BTA) inhibitor was coated in mesoporous silica nanoparticles (MSNs) by tannic acid complex (TAC) deposition. The tannic acid complex film was used as a pH control release valve, which could sensitively feedback and control the release of BTA. MSNs-BTA@TAC was added to the organic–inorganic composite coating, a self-healing coating with pH feedback sensitivity and corrosion compensation function was prepared. The results of electrochemical impedance spectroscopy (EIS) showed that the organic/inorganic composite coating containing 2 wt% MSNs-BTA@TAC nanoparticles showed obvious self-healing effect after soaking in simulated body fluids for 20 days, and its low-frequency impedance modulus increased from 4.9 × 104 Ωcm2 to 9.2 × 105 Ωcm2. The long-term corrosion resistance and self-healing effect of the coating were verified in simulated body fluids.

Model of Reactive Magnetron Sputtering of a Two-Component Composite Target

The article proposes a model for predicting the content of metal components of complex oxide films deposited by reactive magnetron sputtering of a two-component composite target in Ar/O2 gas mixture. The model takes into account the sputtering yield and ion-electron emission coefficients of the sputtered metals and their oxides, the distribution of the ion current density on the target, and the rate of the chemical reaction of the formation of oxides of these metals. To verify the proposed model, studies of the elemental composition of titanium-aluminum oxide films deposited by magnetron sputtering of a Ti-Al composite target in Ar and Ar/O2 gas mixture were carried out. It has been established that the model adequately describes the change in the content of metals in the deposited films with a change in the oxygen flow into the chamber. The simulation error does not exceed 10 %, this makes it possible to use the proposed model for predicting the content of metals in a film during reactive sputtering of two-component composite targets.

On the Role of the Sr3−xCaxAl2O6 Sacrificial Layer Composition in Epitaxial La0.7Sr0.3MnO3 Membranes

AbstractThe possibility to fabricate freestanding single crystal complex oxide films has raised enormous interest to be integrated in next‐generation electronic devices envisaging distinct and novel properties that can deliver unprecedented performance improvement compared to traditional semiconductors. The use of the water‐soluble Sr3Al2O6 (SAO) sacrificial layer to detach the complex oxide film from the growth substrate has significantly expanded the complex oxide perovskite membranes library. Nonetheless, the extreme water sensitivity of SAO hinders its manipulation in ambient conditions and restricts the deposition approaches to those using high vacuum. This study presents a pioneering study on the role of Ca‐substitution in solution processed SAO (Sr3−xCaxAl2O6 with x ⩽ 3) identifying a noticeable improvement on surface film crystallinity preserving a smooth surface morphology while favoring the manipulation in a less‐restricted ambient conditions. Then, the study focuses on the effect of the sacrificial composition on the subsequent ex situ deposition of La0.7Sr0.3MnO3 (LSMO) by pulsed laser deposition, to obtain epitaxial films with a variable degree of strain. Finally, epitaxial and strain‐free LSMO membranes with metal‐insulator transition at 290 K are delivered. This study offers a hybrid and versatile approach to prepare and easily manipulate crystalline perovskite oxide membranes by facilitating ex situ growth on SAO‐based sacrificial layer.

Construction of novel Cu-α-diimide interactions for enhancing thermal resistance and dimensional stability of polyimide films

The new-generation polyimide films with simultaneously outstanding thermal stability and low coefficient of linear thermal expansion (CTE) are urgently needed. Herein, coordination bonds were employed to improve polyimide films' heat resistance and dimensional stability. Polyimide-Cu complex films were fabricated by incorporating α-diimide units (bidentate ligands) into the BPDA-ODA (the structure of commercially available Upilex-R® polyimide films) backbones. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Energy dispersive X-ray mapping results showed that the coordination interactions occur between α-diimide and copper ions. Wide-angle X-ray diffraction (WAXD) and two-dimensional small-angle X-ray scattering (SAXS) spectra demonstrated that Cu-α-diimide coordination structures introduced in intermolecular chains leading polyimide films transformed from a semi-crystalline state to amorphous state, and inhibited the long-period formation structures. The plateau modulus and longer characteristic relaxation time (τ∗ = 1996.5 s) revealed by dynamic thermomechanical analysis indicated that crosslink networks were successfully formed by constructing coordination bonds. As a result, polyimide films' thermal resistance and dimensional stability were simultaneously enhanced. The typical PI-Cu50 films exhibited elevated glass transition temperatures of 353 °C (pristine PI-Cu0 ∼ 302 °C) and a lower CTE of 47.4 ppm/K (pristine PI-Cu0 films ∼ 64.4 ppm/K) in ranges of 300–400 °C, showing a promising application in the field of high-temperature environments.

Nanocomposite thin-film structures based on a polyelectrolyte complex of chitosan and chitosan succinamide with SWCNT

The article is devoted to the study of nanocomposite thin films based on a polyelectrolyte complex of chitosan and chitosan succinamide (PEC). Single-walled carbon nanotubes (SWCNT) were used as fillers. Using the methods of cyclic voltammetry and electrochemical impedance spectroscopy, it was found that nanocomposite films have a larger effective surface area and electron transfer rate compared to polyelectrolyte complex films, which allows them to be further used in the electroanalysis of substances of various nature. The study of the surface of the nanocomposite structure of PEC with SWCNT using SEM showed that there are formations in the form of filaments formed by carbon nanotubes on it. Studying the nature of morphology is extremely important when creating sensory devices. Sensory sensitivity of resistive thin-film nanocomposite structures to air humidity and ammonia vapors was found. Based on these nanocomposite materials, samples of resistive thin-film structures were prepared, the dependences of the flowing current on the relative humidity of the air and the concentration of ammonia vapors were measured.

In Situ Co‐transformation of Reduced Graphene Oxide Embedded in Laser‐Induced Graphene and Full‐Range On‐Body Strain Sensor

AbstractOn‐body strain information provides various indicators such as heart rate, physiological pulse, voice waveform, respiratory rate, and body motion status. Recent advances in wearable strain sensors using nanomaterials have significantly enhanced sensor performance with regard to sensitivity, detectable range, and response time. However, it is still challenging to obtain all types of body strain information, from small vibrations to joint movements, using one type of sensor. Herein, a full‐range on‐body strain (FROS) sensor covering ultrasmall‐to‐large strains such as vocal vibration and joint movement is reported. To achieve an ultrawide detectable range, reduced graphene oxide (rGO)‐embedded laser‐induced graphene (LIG) is synthesized by laser engraving on a graphene oxide (GO)‐embedded polyimide (PI) complex film. An rGO‐LIG homostructure based on sp2‐carbons is photothermally reconstructed from the GO‐PI heterostructure in a complex film by in situ co‐transformation and then transferred to an elastomer substrate. The fabricated FROS sensor successfully performs on‐body strain monitoring of various indicators, such as physiological pulse, vocal sound waveform, and body movement, as well as American sign language translation. Furthermore, it is believed that this rGO‐LIG homostructure‐based material synthesized by in situ co‐transformation can potentially provide novel functionalities in fields such as wearable electronics, humanoid, soft robotics, and intelligent prosthetics.