Alternate Deposition Method Research Articles

Enhancing fire safety, electromagnetic interference shielding, and photothermal conversion performances of wearable polyamide fabrics through eco-friendly coatings

The demand for smart textiles in wearable technology has significantly increased in the last decade. However, the inherent flammability of most textiles poses a big challenge, especially when exposed to elevated surface temperatures induced by electrical or optical stimuli, increasing the risk of fire. The process of synthesizing flame retardants involves the use of organic solvents, which is not in line with the requirements of sustainable development. This research focuses on establishing an eco-friendly and stable coating for polyamide 6 (PA6) fabric through a solvent-free synthesis and innovative alternating deposition method. It has been demonstrated that the treated PA6 fabric exhibits rapid self-extinguishing properties, eliminating melt dripping and achieving a remarkable limiting oxygen index of 25.5%. Furthermore, the peak heat release rate and total heat release rate of the treated PA6 fabric decrease by 32.9% and 22.7%, respectively, compared to that of the control PA6. Under simulated sunlight exposure at an intensity of 150 mW·cm−2, the treated PA6 fabric rapidly reaches a surface temperature of 78.6 °C within 300 s. Additionally, the treated PA6 fabric demonstrates an electromagnetic interference (EMI) shielding efficiency of 24.0 dB in the X-band, highlighting the efficacy of the innovative coating. This result is attributed to the conductive network formed by the alternating deposition of MXene and polyphosphamide. This work not only improves the fire safety in wearable textiles but also presents a promising and green strategy for developing multifunctional wearable textiles with enhanced safety features.

Fabricating large scale titanium alloy thin-walled double-sided part by hot-wire arc additive manufacturing

Using traditional process to fabricate large scale titanium alloy thin-walled part such as wings and grid rudder, has the problem of low material utilization. Wire arc additive manufacturing (WAAM) is a flexible manufacturing technology with high deposition efficiency and high material utilization. In addition, a hot-wire device is attached to the WAAM system as auxiliary heat source, and the WAAM system becomes hot-wire arc additive manufacturing (HWAAM) system. In this paper, a large scale titanium alloy drone frame was fabricated by HWAAM. A double-side alternating deposition method was proposed to reduce the thermal deformation of the substrate. Two additional sections of the drone frame was taken off for mechanical analysis. The shape of the whole drone frame is completed and the mechanical properties meet the requirements of the project.

Preparation Methods for Graphene Metal and Polymer Based Composites for EMI Shielding Materials: State of the Art Review of the Conventional and Machine Learning Methods

Advancement of novel electromagnetic inference (EMI) materials is essential in various industries. The purpose of this study is to present a state-of-the-art review on the methods used in the formation of graphene-, metal- and polymer-based composite EMI materials. The study indicates that in graphene- and metal-based composites, the utilization of alternating deposition method provides the highest shielding effectiveness. However, in polymer-based composite, the utilization of chemical vapor deposition method showed the highest shielding effectiveness. Furthermore, this review reveals that there is a gap in the literature in terms of the application of artificial intelligence and machine learning methods. The results further reveal that within the past half-decade machine learning methods, including artificial neural networks, have brought significant improvement for modelling EMI materials. We identified a research trend in the direction of using advanced forms of machine learning for comparative analysis, research and development employing hybrid and ensemble machine learning methods to deliver higher performance.

Electric transmission behavior of self-assembled Cu–W nano multilayers

Metallic nano multilayers were usually prepared by dual targets alternating deposition method. In this paper, a series of self-assembled Cu–W nano multilayers with different modulation periods were deposited on single crystal silicon substrate by dual targets confocal magnetron sputtering technique. The self-assembled film presented an alternation of W-rich layer and Cu-rich layer. The degree of coherence of the layered interface can be adjusted by controlling both the solid solubility of W-rich and Cu-rich layers. The film resistance increment of the self-assembled Cu–W multilayers is only 14% when the modulation period decreases from 68.2 nm to 5.3 nm, having less size effect compared to the film prepared by alternating deposition method. It noticed that the film resistance even decreased slightly when the modulation period decreased to below 5.3 nm. These results suggested that the coherence could weak the interface scattering ability to electrons, so the self-assembled Cu–W multilayers have lower resistance than the multilayer prepared by alternating deposition technique. This study presented a new pathway to enhance the conductivity of the multilayers.

Precision Mapping of O-Linked N-Acetylglucosamine Sites in Proteins Using Ultraviolet Photodissociation Mass Spectrometry.

Despite its central importance as a regulator of cellular physiology, identification and precise mapping of O-linked N-acetylglucosamine (O-GlcNAc) post-translational modification (PTM) sites in proteins by mass spectrometry (MS) remains a considerable technical challenge. This is due in part to cleavage of the glycosidic bond occurring prior to the peptide backbone during collisionally activated dissociation (CAD), which leads to generation of characteristic oxocarbenium ions and impairs glycosite localization. Herein, we leverage CAD-induced oxocarbenium ion generation to trigger ultraviolet photodissociation (UVPD), an alternate high-energy deposition method that offers extensive fragmentation of peptides while leaving the glycosite intact. Upon activation using UV laser pulses, efficient photodissociation of glycopeptides is achieved with production of multiple sequence ions that enable robust and precise localization of O-GlcNAc sites. Application of this method to tryptic peptides originating from O-GlcNAcylated proteins TAB1 and Polyhomeotic confirmed previously reported O-GlcNAc sites in TAB1 (S395 and S396) and uncovered new sites within both proteins. We expect this strategy will complement existing MS/MS methods and be broadly useful for mapping O-GlcNAcylated residues of both proteins and proteomes.

The surface electrical analysis of Nano Polyurethane-Based Superamphiphobic composite insulation materials

In the early stage of this study, it was found that Polyurethane was only two ways to construct the super-hydrophobic surface. The second is to construct micro-nano structure with low surface energy materials. Specific preparation methods of superhydrophobic surfaces include heterogeneous nucleation method, plasma treatment method, etching method, sol-gel method, vapor deposition method, electrochemical method, alternating deposition method, template method, self-assembly method, solve-non-solvent method, direct film formation method, etc., and many successful examples have been achieved. The research work in this field is relatively few, and the materials involved are scattered. The research objectives are all focused on the construction of micro-nano multistage surface structures with low surface energy. At present, most of these works only test the corresponding electrical properties of superhydrophobic surfaces. In order to verify the application prospect of superhydrophobic surface in antifouling flashover, it is necessary to carry out in-depth research on its hydrophobic, fouling and discharge aspects.

Enhanced selective adsorption of benzotriazole onto nanosized zeolitic imidazolate frameworks confined in polystyrene anion exchanger

A new nanocomposite adsorbent ZIF-67/D201, in which nanocrystalline ZIF-67 were immobilized inside the networking pores of a commercial polystyrene anion exchanger D201 by an alternate deposition method, with high capacity and enhanced selective affinity toward benzotriazole (BTA) was fabricated and characterized. ZIF-67/D201 demonstrated precise selective adsorption of BTA when benzimidazole (BMA), with very similar chemical structure to BTA, coexisted. After the uptake of BTA, ZIF-67/D201 could be regenerated for repeated use with slight capacity loss. According to kinetics data, two diffusion steps driven by electrostatic attraction were found prior to adsorption equilibrium: a fast diffusion of the contaminant into mesopores of D201 and then a relatively slow diffusion into micropores of ZIF-67. The underlying mechanism for the enhanced selective adsorption was revealed by spectral analysis and density functional theory (DFT) calculations. Three sorts of interactions (coordination, electrostatic attraction and π-π interaction) contributed to the fixing of contaminants. Among them, coordination was the predominant effect. For each sort of interaction, the binding energy of adsorbent-BTA was always larger than that of adsorbent-BMA, which was the intrinsic reason of the high selectivity in molecular level. The above results provided a strategy for precise separation of components with similar structures in water.

Reverse gravure coating for roll-to-roll production of organic photovoltaics

Reverse gravure (RG) coating is reported here as an alternate film deposition method for potential large scale roll-to-roll production of organic photovoltaic devices (OPVs). The basic working principles of RG coating are shown and compared to the more well-known gravure printing. Gravure printing is similar to RG coating from a process point of view, but the films produced using each method are very different to each other. An optical thickness measurement system was developed and used to monitor film thickness variation of RG coated photo-active layers with various coating parameters in situ in the roll-to-roll process. Partially and fully printed OPV modules were fabricated using, primarily, the roll-to-roll RG coating process and devices showed 2.1% and 1.5% power conversion efficiencies, respectively.

Magnetic domain observation of FeCo thin films fabricated by alternate monoatomic layer deposition

FeCo thin films are fabricated by alternate monoatomic layer deposition method on a Cu3Au buffer layer, which in-plane lattice constant is very close to the predicted value to obtain a large magnetic anisotropy constant. The variation of the in-plane lattice constant during the deposition process is investigated by reflection high-energy electron diffraction. The magnetic domain images are also observed by a photoelectron emission microscope in order to microscopically understand the magnetic structure. As a result, element-specific magnetic domain images show that Fe and Co magnetic moments align parallel. A series of images obtained with various azimuth reveal that the FeCo thin films show fourfold in-plane magnetic anisotropy along ⟨110⟩ direction, and that the magnetic domain structure is composed only of 90∘ wall.

Preparation and Study of Biomimetic Ring CoCl<sub>2</sub>/CS Biological Bar

Exploring an effective replacement material of bone transplantation to repair bone defect is the hot topic in bone defect therapy at present. The biomimetic materials will be the main dircetion. Chitosan, the N-deacetylated derivative of chitin, has been regarded as suitable materials because of its biocompatibility, biodegradability, reliability and wide sources, which is the next generation of promising materials for tissue engineering. This study introduce the best CoCl2_-Chitosan-gel-sticks of different concentrations prepared by using the in-situ Precipitation Method and Alternate deposition Method. This investigation progeny will have a wide range of applications in biological materials field and other fields.

H2S Micro Gas Sensor Based on a SnO2-CuO Multi-layer Thin Film

This paper proposes a micro gas sensor for measuring <TEX>$H_2S$</TEX> gas. This is based on a <TEX>$SnO_2$</TEX>-CuO multi-layer thin film. The sensor has a silicon diaphragm, micro heater, and sensing layers. The micro heater is embedded in the sensing layer in order to increase the temperature to an operating temperature. The <TEX>$SnO_2$</TEX>-CuO multi layer film is prepared by the alternating deposition method and thermal oxidation which uses an electron beam evaporator and a thermal furnace. To determine the effect of the number of layers, five sets of films are prepared, each with different number of layers. The sensitivities are measured by applying <TEX>$H_2S$</TEX> gas. It has a concentration of 1 ppm at an operating temperature of <TEX>$270^{\circ}C$</TEX>. At the same total thickness, the sensitivity of the sensor with multi sensing layers was improved, compared to the sensor with one sensing layer. The sensitivity of the sensor with five layers to 1 ppm of <TEX>$H_2S$</TEX> gas is approximately 68%. This is approximately 12% more than that of a sensor with one-layer.

Multi-Source/Component Spray Coating for Polymer Solar Cells

A multi-source/component spray coating process to fabricate the photoactive layers in polymer solar cells is demonstrated. Well-defined domains consisting of polymer:fullerene heterojunctions are constructed in ambient conditions using an alternating spray deposition method. This approach preserves the integrity of the layer morphology while forming an interpenetrating donor (D)/acceptor (A) network to facilitate charge transport. The formation of multi-component films without the prerequisite of a common solvent overcomes the limitations in conventional solution processes for polymer solar cells and enables us to process a wide spectrum of materials. Polymer solar cells based on poly(3-hexylthiophene):[6,6]-phenyl C(61) butyric acid methyl ester spray-coated using this alternating deposition method deliver a power conversion efficiency of 2.8%, which is comparable to their blend solution counterparts. More importantly, this approach offers the versatility to independently select the optimal solvents for the donor and acceptor materials that will deliver well-ordered nanodomains. This method also allows the direct stacking of multiple photoactive polymers with controllable absorption in a tandem structure even without an interconnecting junction layer. The introduction of multiple photoactive materials through multisource/component spray coating offers structural flexibility and tenability of the photoresponse for future polymer solar cell applications.

Depositing an Apatite Coating in/on Massive Chitosan Porous Scaffolds by an Alternate Soaking Method

We hope to improve the biological activity and the osteo-conductivity of a porous polymer scaffold by the deposition of a hydroxyapatite (HA) coating. We used an alternate soaking deposition method to prepare HA coating. A massive chitosan (Cs) porous scaffold was used as a deposition template and immersed alternately in calcium chloride and disodium hydrogen phosphate solutions. Finally, a hydroxyapatite coating was deposited in/on the massive chitosan porous scaffold. The compositions, micromorphology, porosity, inorganic deposition amount and compressive strength were characterized by XRD, FT-IR, SEM, porosity measurements, calcination and a compression experiment. Results indicated that the deposition mineral was a low crystallinity carbonate hydroxyapatite with c axis preferential growth and was similar to hydroxyapatite in natural bone. SEM results showed that the sedimentary hydroxyapatite had a gradient distribution in the scaffold. More deposition was observed on the outer pore wall surface than the inner pore wall surface. The exterior pores of the scaffold were partially blocked but the inner pore structure of the scaffold was still interconnected. The porosity of the deposited scaffold was 94.0% and the deposited hydroxyapatite was 13.5% of the total mass after 6 alternate soaking cycles. The compressive strength of the scaffold increased from 0.055 MPa to 0.109 MPa.

Alignment Properties of Photoinduced Alignment Films for Liquid Crystals based on Self-assembled Multilayer Films

A photoalignment film of liquid crystals based on a photosensitive self-assembled multilayer film was investigated. The precursor film was prepared by an alternate deposition method in aqueous solution, and when irradiated by linearly polarized ultraviolet light (LPUVL), the photosensitive double bonds in the film underwent photocycloaddition preferentially along the polarized direction of the LPUVL. The photoalignment film exhibited obvious anisotropy and could induce nematic liquid crystals to align uniformly in the planar state. The azimuthal anchoring energy of the film raised up to 1.5 × 10−5 J/m2. Atomic Force Microscopy (AFM) indicated that the surface of the multilayer film became slightly rougher with increasing thickness of the film layer but the alignment effect became more homogeneous.

Synthesis and Self-Assembled Film Fabricated from Water-Soluble Poly( P-phenylene vinylene) and Fullerene Derivative

Fullerene-containing ammonium was synthesized and the photocurrent generation of self-assembled multilayer film fabricated from [ll-(2,2-dimethyl-[60]fulleropyrrolidin-l-yl)-undecyl]-trimethyl-animonium ( FA) and water-soluble poly( P-phenylene vinylene) using alternate deposition method was also investigated. The self-assembled film exhibits a steady and rapid anodic 2.5 μA cm −2 photocurrent response.

DC conduction properties of Gadolinium–Indium oxide films deposited on Si(1 0 0)

Thin (Gd–In) oxide films were prepared by alternating deposition method on Si (P) substrates to form MOS structures in order to investigate their dc-electrical properties. These films were annealed at different conditions and characterised by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The capacitance–gate voltage ( C– V g) dependence was used to study the effect of annealing conditions on the effective relative permittivity, concentration of the charges in the film, and determination the accumulation voltage region. The dc-current transfer in the samples is studied as a function of gate voltage at accumulation polarity and temperature in the range (293–390 K). The measurements showed ohmic conduction at low voltages. But, at voltages V > 0.4 V, the current transfer followed the trap-charge-limited space-charge-limited conductivity (TCLC–SCLC) mechanism characterised by exponential distribution of traps within the band gap. The total traps concentrations are 4.1 × 10 24 m −3 and 2.2 × 10 24 m −3 for samples annealed in oxygen atmosphere and in vacuum, respectively.

DC electrical measurements on gadolinium–erbium oxide films prepared on Si (100) substrates

Abstract Er doped Gd oxide thin films were prepared by alternating deposition method on Si (P) substrates to form MOS structures. These films were annealed in oxygen atmosphere and in vacuum and characterised by X-ray fluorescence and X-ray diffraction. The capacitance–gate voltage ( C – V g ) dependence was used to characterise the constructed MOS devices and to measure the relative permittivity of the oxide. The dc-current transfer in the samples was studied as a function of gate voltage and temperature in the range of (293–343 K). The measurements showed that for voltages V > 0.8 V, the current transfer followed the trap-charge-limited space-charge-limited conductivity (TCLC–SCLC) mechanism characterised by exponential distribution of traps within the bandgap. The energy distribution of traps and their total concentration were determined.

Electrical and transport properties of europium-indium oxide films prepared on Si(1 0 0) substrates

Thin EU–In binary oxide films were prepared by alternating deposition method on Si (P) substrates to form metal–oxide–Si(MOS) devices. These films were annealed at different conditions and characterised by X-ray fluorescence (EDXRF) and X-ray diffraction (XRD). The capacitance–gate voltage ( C– V g) dependence was used to investigate the effect of annealing conditions on the trapped-fixed charge concentration in the oxide and on the relative permittivity of the film sample. It was observed that the prepared crystalline-dielectric Solid Solution (SS) of EU–In oxide has a sufficiently high relative permittivity ε , around 30. This suggests that it is a promising candidate for high- ε dielectric applications. The DC electrical properties of EU–In binary oxides insulator were investigated. The current–voltage J( V g) and current–temperature J( T) characteristics refer to different current transfer processes depending on the annealing conditions, i.e., on the structure and trap concentration. The current transfer in the oxide film sample with mixed amorphous Eu oxide and polycrystalline In 2O 3 is governed by Poole–Frenkel (PF) mechanism of barrier height 0.15 eV while in the oxide film with mixed polycrystallines Eu 2O 3 and In 2O 3 follows the trap-charge-limited space-charge-limited conductivity (TCLC–SCLC) mechanism characterised by exponential distribution of traps of temperature parameter of 512.8 K and total trap concentration ( N t) of 4.2×10 22 m −3. The current transfer in MOS device with dielectric solid solution of EU–In oxide follows the TCLC–SCLC mechanism with temperature parameter of 427.8 K and N t of 2.2×10 23 m −3. It was concluded that the carrier traps in those crystalline films are distributed exponentially in energy within the band gap. These concentrations N t were compared with the concentrations of the fixed charges in the films calculated from the capacitance measurements, which was around 10 22 charges/m 3.

An activated carbon substrate surface for laser desorption mass spectrometry

A method to obtain laser desorption/ionization mass spectra of organic compounds by depositing sample solutions onto a carbon substrate surface is demonstrated. The substrate consists of a thin layer of activated carbon particles immobilized on an aluminum support. In common with the porous carbon suspension samples used in previous “surface-assisted laser desorption/ionization” (SALDI) work, the mass spectra contain only a few “matrix” background ion peaks, minimizing interference with analyte ion peaks. The presence of glycerol ensured that the ion signals were stable over hundreds of laser shots. In addition, the carbon substrate surface has several advantages over the suspension samples. The use of a very thin layer of carbon significantly improves the sensitivity. Detection limits range from attomoles for crystal violet to femtomoles for bradykinin. Very little sample preparation is required as the analyte solution is simply pipetted onto the substrate surface and glycerol added. When using an alternate sample deposition method, a mass resolution for bradykinin of 1800 is achieved in linear time-of-flight mode. This is close to the resolution limit set by the detector system and above instrument specification for matrix-assisted laser desorption/ionization mass spectra.

Self-control Phenomenon for Crystallinity and Morphology Observed at Epitaxial Growth of BaTiO3 by Alternating Deposition Method

ABSTRACTWe directly observed self-control crystallization of epitaxial BaTiO3 films during alternate depositions of BaO and TiO2. When TiO2 (or BaO) was supplied excessively, surface crystallinity and smoothness degraded due to three-dimensional (3D) growth. However, when the following BaO (or TiO2) was supplied onto the rough TiO2 (or BaO) surface, the surface smoothness was recovered drastically. It was found that a single phase BaTiO3 film grew by repeating the alternate deposition cycle of excessive supply of both BaO and TiO2. The mechanism of this phenomenon was discussed.