Complex Films Research Articles

Chitosan-polygalacturonic acid complex dressing improves diabetic wound healing and hair growth in diabetic mice

Chronic skin wounds decrease the quality of life of millions of diabetic patients worldwide. Chitosan has previously been shown to possess hemostatic properties, decrease inflammation, promote fibroblast proliferation, and hair growth. We developed a relatively low-cost polyelectrolyte complex (PEC) film dressing made of chitosan and polygalacturonic acid and tested it for its ability to accelerate diabetic wound healing. Genetically diabetic male mice were shaved on the dorsum, and one day later a 1 cm diameter full-thickness excisional wound was created. The PEC film was applied immediately after wounding and left in place for 14 days. Controls consisted of wounds treated with a fibrin gel. Wounds covered with the PEC film had closed completely by post-wounding day 42, while untreated wounds were only half-way closed. Histological analysis of wounds confirmed that PEC-treated wounds had fully re-epithelialized, while control wounds lacked a continuous epidermis at the wound center. We also observed that the area of skin under the PEC film experienced much more rapid hair growth. Histologically, there were significantly more hair follicles around the scar area (p < 0.05) in the PEC-treated group as compared to the control group. Thus, chitosan-polygalacturonic acid PEC films can accelerate both wound healing and hair growth in diabetic mice, and should be further investigated as a potential future treatment for diabetic chronic wounds.

Design of Promising Uranyl(VI) Complexes Thin Films with Potential Applications in Molecular Electronics.

In this work, it is proposed the development of organic semiconductors (OS) based on uranyl(VI) complexes. The above by means of the synthesis and the characterization of the complexes by Infrared spectroscopy, Nuclear magnetic resonance spectroscopy, mass spectrometry, and X-ray diffraction. Films of these complexes were deposited and subsequently, topographic and structural characterization was carried out by Scanning Electron Microscopy, X-ray diffraction, and Atomic Force Microscopy. Additionally, the nanomechanical evaluation was performed to know the stiffness of uranyl films using their modulus of elasticity. Also, the optical characterization took place in the devices and their bandgap value ranges between 2.40 and 2.93 eV being the minor for the film of the uranyl complex with the N on pyridine in position 4 (2 c). Finally, the electrical behavior of the uranyl(VI) films was evaluated, and important differences were obtained: the uranyl complex with the N on pyridine in position 2 (2 a) film is not influenced by changes in lighting and its current density is in the order of 10-3 A/cm2. The film with uranyl complex with the N on pyridine in position 3 (2 b) and 2 c presents a greater current flow under lighting conditions and two orders of magnitude larger than in film 2 a. In these films 2 b and 2 c, ohmic behavior occurs at low voltages, while at high voltages the charge transport changes to space-charge limited current behavior.

Preparation, physicochemical properties, antioxidant, and antibacterial activities of quaternized hawthorn pectin films incorporated with thyme essential oil

To investigate the impacts of thyme essential oil (TEO) on the structural, physical, antioxidative, and antibacterial properties of quaternized pectin film (QHP), the 0.5%, 1.0%, and 1.5% TEO were incorporated to prepare quaternized pectin and TEO composites films. Scanning electron microscopy (SEM) pictures of the apparent morphology revealed that TEO had good compatibility with quaternized pectin. With TEO combined, the thickness and opacity of films increased, while the water content and swelling degree decreased. TEO has a plasticizing effect on films and improve the elongation at the break of films. However, hydrophobic TEO did not improve the hydrophobicity and water vapor barrier performance of films. The complex of TEO had slight influence upon the thermal stability of films. The composite films exhibited higher UV shielding, antioxidative, and antibacterial performance. Thus, the complex films have potential application value in active food packaging materials.

Corrosion inhibition of 8-HQ for AA5052 in 3 wt% NaCl solution in presence of trace Cu2+ ions: Electrochemical/surface studies, DFT/MD modeling

In this paper, the effect of Cu2+ ions on corrosion inhibition of 8-hydroxyquinoline (8-HQ) for AA5052 aluminum alloy in the simulated seawater solution has been studied by weight loss experiments, electrochemical measurements and surface analysis. 8-HQ inhibits the corrosion of AA5052 aluminum alloy in 3 wt% NaCl solutions very well, resulting in a positive shift in corrosion potential. The 0.01 mg/L of Cu2+ ions can deteriorate the corrosion inhibition of 8-HQ at low concentrations. This behavior is interpreted on the basis of deposition of copper by displacement on the defects of the corrosion inhibition film of 8-HQ. When the concentration of 8-HQ reached 5 mg/L, the presence of 0.01 mg/L Cu2+ ions increase the corrosion inhibition efficiency of 8-HQ by 6.27%. 8-HQ shows efficient inhibition at a relative high concentration, suggesting that the chelate formed by Cu2+ ions and 8-HQ can repair the defects of the 8-HQ inhibitive film on aluminum surface. The complex film would suppress the partial cathodic reaction and lead to the improved corrosion inhibition.

Synthesis and structures of cobalt-expanded zirconium- and cerium-oxo clusters as precursors for mixed-metal oxide thin films.

Transforming current complementary metal-oxide-semiconductor (CMOS) technology to fabricate memory chips and microprocessors into environmentally friendlier electronics requires the development of new approaches to resource- and energy-efficient electron transport and switching materials. Metal and multi-metal oxide layers play a key role in high-end technical applications. However, these layers are commonly produced through high-energy and high-temperature procedures. Herein, we demonstrate our first attempts to obtain stimuli-responsive mixed-metal oxide thin films from solution-processed molecular precursors under milder conditions. The molecular compounds of interest were prepared by one-pot reactions of a CoII carboxylate complex, triethylamine (Et3N), N-butyldiethanolamine (H2bda), and a hexanuclear complex [Ce6O4(OH)4(piv)12] (Hpiv = pivalic acid) or [Zr6O4(OH)4(ib)12(H2O)]·3Hib (Hib = isobutyric acid) in acetonitrile solution. The resulting charge-neutral, heterometallic coordination compounds display a ligand-supported pentanuclear {CeIV3CoIII2} core (in 1) and a dodecanuclear {ZrIV6CoII6} core (in 2), exhibiting thermal stability up to ca. 100 °C in air. Compound 2 was deposited and analyzed on Au(111) and SiO2/Si(100) surfaces to explore its potential as a single-molecule precursor for the preparation of atomically precise, complex mixed-metal oxide thin films. The adsorption characteristics of it demonstrate the ability to form stable agglomerates on the investigated surfaces.

Influence of misfit dislocations on ionic conductivity at oxide interfaces

Mismatched complex oxide thin films and heterostructures have gained significant traction for use as electrolytes in intermediate temperature solid oxide fuel cells, wherein interfaces exhibit variation in ionic conductivity as...

FeVO4-based solution-processed all oxide self-biased fast photodetectors

A solution-processed all-oxide self-biased FeVO4–NiO n–p heterojunction-based fast photodetector is prepared that maintains its performance after dropwise adding water onto the pristine device, and drying at a temperature of 120 °C.

Films of linear conjugated polymer as photoanodes for oxidation reactions.

Photoelectrochemical (PEC) devices hold huge potential to convert solar energy into chemical energy. However, the high cost of raw materials and film processing has hindered its practical use. In this study, we attempt to tackle this issue by fabricating straightforward semiconducting polymer films. These films function as photoanodes for various oxidation reactions, including water oxidation and oxidative organosynthesis. The structures of the polymer were assessed by incorporating electron-rich and electron-deficient co-monomers into dibenzo[b,d]thiophene sulfone materials. Furthermore, to gain comprehensive insight into the performance, we conducted both steady-state and in operando investigations, revealing that the active site on the polymer surface determines the rate of the conversion process. This study marks a significant stride towards leveraging economically viable semiconductors in PEC systems for efficient solar-to-chemical conversions. It addresses the challenges of high material costs and complex film processing, paving the way for the scaled-up application of this burgeoning technology.

Structures and Antibacterial Properties of DNA Ion Complex Films Consisting of Different Cationic Surfactants with the Same Carbon Number in Their Tails

Structures and Antibacterial Properties of DNA Ion Complex Films Consisting of Different Cationic Surfactants with the Same Carbon Number in Their Tails

Insufficient sleep blunts positive, but not negative, affective response to emotionally complex film clips.

The effects of sleep deprivation on emotional function are not yet fully understood. Although sleep deprivation has been shown to have larger effects on positive emotional reactivity than on negative, this research has been limited by the use of separate stimuli for positive and negative emotion elicitation. Different sets of stimuli represent a confound that makes it difficult to interpret this difference with confidence. The study reported here was designed to overcome this limitation by using film clips that elicit both positive and negative emotional responses at the same time. Undergraduate participants (33 female, 2 male) completed a laboratory-based emotion elicitation procedure using these film clips. Differences in sleep deprivation, estimated by subjective sleepiness and reaction times, were used to predict responses to these emotion probes. Greater subjective sleepiness was associated with significantly lesser positive responses to the film clips (rs = -0.37, p = 0.03). The relationship between subjective sleepiness and negative responses to the same clips was smaller and not significant (rs = -0.11, p = 0.51). Reaction times were not related to subjective emotional responses in this sample (all p > 0.40). These results support the theory that sleepiness has asymmetrical effects on positive and negative emotional functioning.

Ultrahighly Sensitive Surface-Enhanced Raman Spectroscopy Film of Silver Nanoparticles Dispersed in Three Dimensions on a Thin Alumina Nanowire Framework.

To develop highly sensitive surface-enhanced Raman spectroscopy (SERS) films, various types of aggregated Ag nanowire (NW) and nanoparticle (NP) complex structures were fabricated using anodic aluminum oxide (AAO) templates and thermal evaporation. Aggregated AgNW structures with numerous tapered nanogaps were fabricated via Ag deposition on aggregated thin alumina nanowires of different lengths. AgNP complex structures were obtained by collapsing vertically aligned thin alumina nanowires 1 μm in length and depositing AgNPs on their tops and sides using surface tension during ethanol drying after functionalization. The Raman signal enhancement factors (EFs) of the samples were evaluated by comparing the SERS signal of the thiophenol (TP) self-assembled monolayer (SAM) on the nanostructures with the Raman signal of neat TP. EFs as high as ~2.3 × 107 were obtained for the optimized aggregated AgNW structure (NW length of 1 μm) and ~3.5 × 107 for the optimized AgNP complex structure. The large EF of the AgNP complex film is attributed mainly to the AgNPs dispersed in three dimensions on the sides of the thin alumina nanowires, strongly implying some important, relevant physics yet to be discovered and also a very promising nanostructure scheme for developing ultrahighly sensitive SERS films with EF > 108.

Benzothiazole-based ionic liquids as environment-friendly and high-efficiency corrosion inhibitors for mild steel in HCl: Experimental and theoretical studies

Two benzothiazole ionic liquids – (E)-3-ethyl-2-(4-hydroxystyryl) benzo[d]thiazol-3-ium iodide ([EHSBT]I) and (E)-3-ethyl-2-(4-hydroxystyryl)benzo[d]thiazol-3-ium bromide ([EHSBT]Br) generate the outstanding protection when employed as green corrosion inhibitors for the steel against aggressive acid solution at different temperatures. The corrosion efficiency of [EHSBT]I and [EHSBT]Br with the low dosage of 0.2 mM is 98.16 % and 89.68 %, respectively, at 303 K. The corrosion inhibition efficiency of [EHSBT]I decreases with the increased temperature and [EHSBT]Br is the opposite. Fortunately, both [EHSBT]I and [EHSBT]Br exhibit the inhibition efficiency of greater than 95 % even when it achieves 333 K, which is ascribed to the dominant chemical adsorption. Likewise, the electrochemical investigation presents the increasement of the charge transfer resistance and interfacial electric double layer thickness due to their adsorption on the substrate, restraining the metal dissolution and hydrogen evolution. The findings of the surface structure and appearance using UV–vis, FT-IR, XPS, SEM-EDS, AFM suggest that the inhibitors can form the complex film ([EHSTB]I-Fe, [EHSTB]Br-Fe) to shield the metal from corrosive particulates via chemical bonding. The confirmation of the active sites and adsorption configuration through theoretical calculation such as DFT and MD, along with RDF, promotes a further comprehension of the corrosion mitigation mechanism, which coincides with the experimental conclusion that the preparation of a stable protective film realizes the superior inhibition performance against high temperature acid corrosion.

Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-β-cyclodextrin complex film for pork freshness monitoring and maintenance

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-β-cyclodextrin complex (Cur-β-CD) was prepared. The CS/P/CP/Cur-β-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10−11 g·(m·s·Pa)−1), and oxygen (1.50 ± 0.06 × 10−12 g·(m·s·Pa)−1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-β-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

Structure and Physico-Mechanical Properties of Polyelectrolyte Complexes Based on Sodium Carboxymethylcellulose Polysaccharide and Polyacrylamide

In this paper, the structure and physico-mechanical properties of films of polyelectrolyte complexes (PEC) based on sodium carboxymethylcellulose (Na-CMC) with linear polyacrylamide (PAA) have been studied. Polyelectrolyte complexes were obtained by mixing aqueous solutions of Na-CMC and PAA components in various ratios of components and pH of the medium. The structure of the obtained products was determined using IR spectroscopy and electron microscopy. IR spectra in the range 400–4000 cm-1 were recorded on NIKOLET Magna-560 IR and Specord-75IR spectrophotometers (Carl Zeiss, GDR). The mechanical properties of films of polyelectrolyte complexes were determined by stretching at a constant speed of movement of the lower clamp, 50 mm/min, on an Instron-1100 automatic dynamometer (England) at room temperature. IR spectroscopic data showed that polyelectrolyte complexes based on Na-CMC and PAA were stabilized due to the cooperative ionic bond between Na-CMC carboxylate anions (-COO-) and amine groups (-NH2) of polyacrylamide. It is shown that PEC films with an equimolar ratio of Na-CMC and PAA components have an increased value of mechanical strength (σр = 38 MPa), elastic modulus (Е = 73 MPa) and a minimum relative elongation (ε = 0.5%). And in excess of Na-CMC or PAA leads to a decrease in mechanical strength and elastic modulus, which is associated with a decrease in the frequency of intermolecular bonds. It has been ascertained that water-soluble polyelectrolyte complexes based on Na-CMC and PAA with increased strength properties can be obtained from solutions of components taken at an equimolar ratio of interacting components. By changing the ratio of components, properties such as mechanical strength, modulus of elasticity and elongation can be controlled. This can serve as one of the means of controlling the structure and properties of Na-CMC and PAA polyelectrolyte complexes. The regulation of the physico-mechanical properties of PEC films opens up wide opportunities for their use as a soil structure former in agriculture and water management and as the basis for soft drugs in pharmacy.

Alginate–Chitosan Polyelectrolyte Complexes As Carriers for Fluorinated Tetraphenylporphyrin in Photosensitizing Systems of Singlet Oxygen Generation

Water-insoluble photosensitizing (PS) systems active in the generation of singlet 1O2 oxygen are obtained by immobilizing fluorinated tetraphenylporphyrin (FTPP) from a solution in acetone on films of polyelectrolyte complexes based on sodium alginate (SA) and chitosan (CT), and on solid water-insoluble gels of alginate and chitosan. The obtained polymer PS systems are used to establish the intensity of the photoluminescence of singlet oxygen in D2O and the activity of the photocatalytic oxidation of tryptophan in water. It is shown that the photocatalytic activity in the tryptophan oxidation of fluorinated tetraphenylporphyrin immobilized on a SA–CT polyelectrolyte complex and alginate solid gel is higher than that of FTPP immobilized on chitosan solid gel. Spectral-luminescent properties of polysaccharide–FTPP systems and the surface structure of carriers are studied via atomic force microscopy to determine the mechanism of the increase in porphyrin activity when it is fixed on alginate-containing carriers. It is suggested that aspects of the supramolecular structure of solid gels are responsible for the increase in the photocatalytic activity of FTPP upon immobilization on alginate-containing polysaccharide systems.

Analysis of the Chemical Composition and Structure of Micrometer-Thick Complex Oxide Films: A Case Study of a MgAl2O4 Film on SiO2 Using Electron Probe Microanalysis and Confocal Raman Spectroscopy

Methodological approaches to both qualitative structural analysis and quantitative compositional analysis of transparent complex oxide films on dielectric substrates, performed using a Horiba LabRAM HR800 confocal Raman spectrometer and a Cameca SX100 electron probe microanalyzer, are described. The studies were carried out using magnesium–aluminum spinel films of a thickness of 1–3 µm on a quartz glass substrate, obtained by magnetron sputtering. The characterization of the film structure consisted of recording 3D arrays of its Raman spectra based on z depth profiling. The film has a disordered spinel structure with a partially reversed distribution of Mg and Al cations over octa- and tetra-positions. Operation parameters are identified to evaluate the concentration of structure-forming elements (Mg and Al) and impurities (Ti, Cr, Ca, P, Fe, Ni, and Gd) in the film using various X-ray emission lines (optimal accelerating voltage, etc.). The performance of the procedure was determined, and its capabilities and limitations were assessed. The resulting data on the chemical composition of the film are presented.

Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water-Etching and Transfer Process

HighlightsThe (001)-oriented ferromagnetic La0.67Sr0.33MnO3 films are stuck onto the (011)-oriented ferroelectric single-crystal 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 substrate with 0° and 45° twist angle.By applying a 7.2 kV cm−1 electric field, the coexistence of uniaxial and fourfold in-plane magnetic anisotropy is observed in 45° Sample, while a typical uniaxial anisotropy is found in 0° Sample.Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering. In recent years, lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations. Moreover, twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures. A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process, which could provide some insight in to the physical phenomena. In this work, the La0.67Sr0.33MnO3 (001)/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (011) (LSMO/PMN-PT) heterostructures with 45º and 0º twist angles were assembled via water-etching and transfer process. The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO < 110 >. A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO [110] easy axis is observed for the 45° Sample by applying a 7.2 kV cm−1 electrical field, significantly different from a uniaxial anisotropy with LSMO [100] easy axis for the 0° Sample. The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45° twist angle causes different lattice distortion of LSMO, thereby enhancing both the fourfold and uniaxial anisotropy. This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

The Cinematic Symphony of Sound: An Analysis of the Music and Sound Effects in "Tenet"

This article presents a thorough dissection of the sound design within the film "Tenet," investigating the crucial role of sound in narrative cinema, and how judiciously chosen sound elements can amplify the emotional resonance of a film. As technology has raced forward, film scores have embraced an eclectic mix of musical styles, including neosymphonic, minimalist, pop, and jazz influences, increasingly blurring the lines between electronic music and other sonic sources. Director Christopher Nolan is celebrated for his unique artistic framework and his penchant for non-linear narratives, while composer Ludwig Göransson has infused the score with avant-garde electronic music styles and techniques to articulate the film's complex temporal narrative. The analysis underscores the exactitude in sound selection, the consonance between musical themes and the cinematic story, the alignment of character idiosyncrasies with the temporal and spatial context of scenes, and the indistinct boundaries between sound effects and music. Moreover, by melding electronic music technologies with Wagnerian leitmotif methods, the film is endowed with a distinctive auditory style. The article's ultimate goal is to transpose these cutting-edge creative concepts into the realm of music composition for various media formats.

Passive behaviour of non-equiatomic NiCoCrTa multi-principal element alloys in dilute sulfuric acid

The passive behaviour of non-equiatomic multi-principal element alloys, Ni(58-x)Co20Cr22Tax (x = 0, 0.64, 1.64, 3.39 at.%), was investigated in 0.1 M H2SO4 at 25 °C by electrochemical methods and surface analysis. After 24 h immersion, the alloys were all found to be in a spontaneously passivated state, and the value of the open circuit potential shifted to the positive direction with the increase of Ta content. The grain size of the alloys reduced with increasing the Ta content. The relationship between the passive current density and the grain size was in agreement with a linear model. The capacitance measurements indicated that the passive film formed on the alloys was of n-type semiconductor characteristic and the donor density was decreased with the increase of Ta. The thickness of the passive film improved primarily due to the obstacle to the dissolution of the outer layer as the accumulation of Ta2O5 in the outer layer. The improved corrosion resistance of the alloys with increasing Ta content can be ascribed to the formation of a complex film containing more Ta2O5, which enhanced the stability, thickness, and compactness of the passive film. The developed alloys show good passivity in dilute sulfuric acid.

Antifouling Coatings from Glassy Polyelectrolyte Complex Films.

Coatings that prevent or decrease fouling are sought for many applications, including those that inhibit the attachment of organisms in aquatic environments. To date, antifouling coatings have mostly followed design criteria assembled over decades: surfaces should be well/strongly hydrated, possess low net charge, and maintain a hydrophilic character when exposed to the location of use. Thus, polymers based on ethylene glycol or zwitterionic repeat units have been shown to be highly effective. Unfortunately, hydrated materials can be quite soft, limiting their use in some environments. In a major paradigm shift, this work describes glassy antifouling films made from certain complexes of positive and negative polyelectrolytes. The dense network of electrostatic interactions yields tough materials below the glass transition temperature, Tg, in normal use, while the highly ionic character of these polyelectrolyte complexes ensures strong hydration. The proximity of equal numbers of opposite charges within these complexes mimics zwitterionic structures. Films, assembled layer-by-layer from aqueous solutions, contained sulfonated poly(ether ether ketone), SPEEK, a rigid polyelectrolyte that binds strongly to a selection of quaternary ammonium polycations. Layer-by-layer buildup of SPEEK and polycations was linear, indicating strong complexes between polyelectrolytes. Calorimetry also showed that complex formation was exothermic. Surfaces coated with these films in the 100 nm thickness range completely resisted adhesion of the common flagellate green algae, Chlamydomonas reinhardtii, which were removed from surfaces at a minimum applied flow rate of 0.8 cm s-1. The total surface charge density of adsorbed cations, determined with a sensitive radioisotopic label, was very low, around 10% of a monolayer, which minimized adsorption driven by counterion release from the surface. The viscoelastic properties of the complexes, which were stable even in concentrated salt solutions, were explored using rheology of bulk samples. When fully hydrated, their Tg values were observed to be above 75 °C.