Post-treatment Method Research Articles

Versatile and Fast Electrochemical Activation Method for Carbon Nanotube Fibers with Diverse Active Materials.

In this study, the challenge of non-electrochemical activity in carbon nanotube fibers (CNTFs) is addressed by developing a modified chlorosulfonic acid (CSA) densification process specifically developed for directly spun CNTFs. This post-treatment method, well-known for enhancing the physical properties of CNTFs, utilizes the double diffusion phenomenon to efficiently integrate a diverse range of active materials, from conductive polymers like polyaniline (PANI) to metal oxides like nickel oxide (NiO), into the fibers. This universal and cost-effective approach not only simplifies the integration process but also significantly boosts both the electrochemical and physical properties of the fibers. For instance, the PANI@CNTF composite exhibited a remarkable 17-fold increase in specific capacitance and a two-fold increase in load value compared to its pristine counterparts. This method proves straightforward, efficient, and versatile, making it suitable for developing fiber-shaped electrodes that advance the capabilities of wearable energy storage systems.

Analysis of Post-Treatment Heating of Stretchable Piezoelectric Electrospun Nanofibers

Electrospun piezoelectric nanofibrous membrane developed from Polyvinylidene fluoride (PVDF) embedded with thermoplastic polyurethane (TPU) composites found to have superior stretchability and piezoactivity. The piezoresponse behavior of different in-situ bended PVDF/TPU, up to 15wt.% of TPU, is examined using various blending ratios of PVDF and TPU. It has been shown that adding TPU with PVDF at certain specific concentration increased the nanofiber's piezo-efficiency.The generated nanomembranes are annealead at different temperatures up to 100°C. An extensive analysis of the effects of annealing is conducted on these nanomats, and it is thought to be a crucial post-treatment method for improving the piezoresponse of the manufactured nanomats. Nanofibers annealed at 100°C showed best effective response compared to all other samples and this revealed the effectiveness of annealing treatment in the enhancement of piezoactivity. The best effective composition of PVDF with 15 wt% TPU after an annealing treatment of 100°C generated a maximum voltage of 3.2 V under the effect of an applied force of 3 N, where unannealed sample of the same PVDF-TPU composition generated only a voltage of 2.2 V. This annealed piezo nanogenerator (PNG), can be considered an optimum option for electromechanical energy harvesting applications that require flexibility and self-power.

Fabrication of an antibacterial polybenzimidazole/Ag@UiO-66-NH2 mixed matrix membrane for dye-salt separation: Solvent evaporation effects

In textile water treatment, nanofiltration membranes are susceptible to biofilm layer formation on their surface due to microbial colonization, which can significantly reduce the separation efficiency of the membrane. Therefore, maintaining long-term antimicrobial efficacy of the membrane is of paramount importance. In this study, UiO-66-NH2 nanoparticles were fabricated via the solvothermal method, then Ag-loaded UiO-66-NH2 (Ag@UiO-66-NH2) nanoparticles were produced by stirring and reduction with silver nitrate solution, and the nanoparticles were integrated into the polybenzimidazole (PBI) matrix through a blending process to fabricate mixed matrix membranes (MMMs) with antimicrobial properties. During the preparation of mixed matrix membranes, the phenomenon of nanoparticle agglomeration on the membrane surface is frequently encountered. In order to solve this problem, we used solvent evaporation and cross-linking post-treatment methods to further improve the compatibility between the membrane and the particles, the membranes showed a good water flux (53.7 L·m−2·h−1), excellent separation capabilities for dyes and salts, NaCl rejection (9.50 %), Na2SO4 rejection (12.70 %), MgCl2 rejection (7.44 %), MgSO4 rejection (9.34 %), Crystal violet, Acid fuchsin, Congo red, Coomassie brilliant blue and Acid red 94 dyes rejection (all over 99 %). And the antibacterial rate is 98.7 % against E. coli and 99.1 % against S. aureus and it has the function of long-term stable Ag+ release.

Structural evolution of iron components and their action behavior on lignite combustion

Spontaneous combustion of lignite is closely related to the inherent minerals it contains, and the iron component has a remarkable influence on the combustion property of lignite. It is very important to study the influence of iron component on the combustion reaction property of lignite to reveal autoignition mechanism of lignite and reduce autoignition of lignite. In this research, FeCl3 and Fe2O3 were doped into demineralised lignite (SL+) by impregnation to research the effects of iron salts and iron oxides on the combustion properties of lignite. Based on the above, the effects of post-treatment method of the FeCl3-doped coal samples, iron-salt hydrolysis products and heat-treated temperatures on the combustion property of lignite were researched, and the microstructures of the coal samples were characterised and analysed using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that doping with FeCl3 increases the combustion performance of lignite, thereby reducing the ignition temperature of lignite by approximately 112 °C. In contrast, doping with Fe2O3 has a weaker combustion-promoting effect. XRD and XPS characterisation indicates that iron species in the coal samples doped with iron salts are highly dispersed and exhibit the FeOOH structure, whereas iron species in the coal samples doped with Fe2O3 exhibit the crystal form of α-Fe2O3. Doping of lignite with FeCl3 and its hydrolysis product β-FeOOH reduces the ignition temperature of the coal samples. Iron species in the FeCl3-doped coal samples after heat treatment at 300 °C-500 °C increase the combustion property of the coal samples, whereas iron species after heat treatment at 600 °C-900 °C have a much weaker or non-existent promoting effect on the combustion performance of the coal samples. The characterisation show a change in iron species in the coal samples with the rise in the heat treatment temperature. This change progresses from highly dispersed β-FeOOH below 300 °C to Fe3O4 above 400 °C. Fe3O4 is gradually reduced, with part of it further reduced to elementary iron at the same time as grain growth. It is believed that the gradual agglomeration of Fe3O4 and the appearance of elementary iron are the main reasons for the weakening or disappearance of the promoting effect on coal combustion.

Ultrasonic shot peening (USSP) post-treatment of Ni laser cladding on mild steel

The ultrasonic shot peening (USSP) technique serves as a reliable post-treatment method for various industrial components to prevent functional failures. This study aims to develop hybrid Ni claddings approximately 300 µm thick on mild steel using laser cladding (LC) and USSP techniques. Morphological studies reveal that the claddings exhibit enhanced closure of cracks, increased hardness, and improved scratch resistance after peening. XRD analysis confirms the presence of compressive residual stress, as well as grain refinement and texturing effects after the peening. Furthermore, the research endeavors to improve their mechanical and electrochemical properties by employing USSP's varied process parameters in a hybrid approach. After undergoing USSP treatment, the average surface roughness was increased by up to 6 µm due to the formation of dimples, while it was 8 µm in the as-cladded and only 1.5 µm after polishing. Furthermore, compared to the as-cladded and polished claddings, the hybrid claddings exhibit a hydrophobic character linked to improved corrosion resistance and better in-depth roughness profiles.

Insight into the coke alleviation pattern over iron-based and boron-modified HZSM-5 bifunctional catalyst for direct CO2 hydrogenation to aromatics

Carbon dioxide (CO2) hydrogenation to aromatics is promising for reducing the burden of petroleum fuels. Herein, iron-based catalyst was mixed with boron modified HZSM-5 with pre-treatment and post-treatment method. The textural, acidic and element distribution properties over zeolite framework and external surface were studied. Combining with characterizations for internal and external coke, the element distribution-acidity-coke-stability relationship over boron-modified zeolite was put forward. Pre-treated zeolite witnessed reduced amount of external and total Brönsted acid sites (BAS) with similar degree, and increase paired Al (Alpair) fraction in the intersection site, leading to increased aromatics selectivity and reduced coke amount. While boron post-treatment significantly reduced external surface BAS and inhibited formation of condensed external coke. Afterwards, the mechanism of olefins aromatization was studied and found that PT-Z5-B greatly suppressed the overalkylation of light aromatics, thus alleviating the co-deactivation pattern generated by transformation of coke precursors from zeolite to iron-based catalyst.

Facile preparation of vanadium oxide films under varied calcination temperature and their multicolor electrochromic behaviors

A vanadium oxide (VO) film was prepared on indium tin oxide (ITO) glass using a simple electrophoretic method and the VO film and its device demonstrated multicolor electrochromic properties of yellow, green, orange-red, and their intermediate colors. The X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) were employed to characterize the composition of the as-prepared films. The ratio of V5+/V4+ in the XPS is significantly different in the yellow, green, and orange-red states and this ratio can be adjusted by applied voltages. The detailed effect of calcination temperature as a post-treatment method on the electrochromic performance of VO film was explored. With the increase of calcination temperature, the optical modulation ability of the films was enhanced, and the color change contrast of the films was most obvious at 200 °C. Meanwhile, the cyclic stability of the VO films was also enhanced. The cyclic voltammetry (CV) curves show that the prepared V2O5 films have high cyclic stability at a calcination temperature of 300 °C. The color efficiency (CE) values of the VO devices were 3.4 cm2C-1 (from initial yellow to green) and 21.6 cm2C-1 (from green to orange-red) at 700 nm, and the coloring time (Tc) and bleaching time (Tb) of the VO devices were 6 s and 10 s, respectively. This work develops a simple and environmentally friendly method to prepare VO films and their devices with multicolor electrochromic properties.

A Review of Wide Bandgap Semiconductors: Insights into SiC, IGZO, and Their Defect Characteristics.

Although the irreplaceable position of silicon (Si) semiconductor materials in the field of information has become a consensus, new materials continue to be sought to expand the application range of semiconductor devices. Among them, research on wide bandgap semiconductors has already achieved preliminary success, and the relevant achievements have been applied in the fields of energy conversion, display, and storage. However, similar to the history of Si, the immature material grown and device manufacturing processes at the current stage seriously hinder the popularization of wide bandgap semiconductor-based applications, and one of the crucial issues behind this is the defect problem. Here, we take amorphous indium gallium zinc oxide (a-IGZO) and 4H silicon carbide (4H-SiC) as two representatives to discuss physical/mechanical properties, electrical performance, and stability from the perspective of defects. Relevant experimental and theoretical works on defect formation, evolution, and annihilation are summarized, and the impacts on carrier transport behaviors are highlighted. State-of-the-art applications using the two materials are also briefly reviewed. This review aims to assist researchers in elucidating the complex impacts of defects on electrical behaviors of wide bandgap semiconductors, enabling them to make judgments on potential defect issues that may arise in their own processes. It aims to contribute to the effort of using various post-treatment methods to control defect behaviors and achieve the desired material and device performance.

Electrospun PVDF-Based Polymers for Lithium-Ion Battery Separators: A Review

Lithium-ion batteries (LIBs) have been widely applied in electronic communication, transportation, aerospace, and other fields, among which separators are vital for their electrochemical stability and safety. Electrospun polyvinylidene fluoride (PVDF)-based separators have a large specific surface area, high porosity, and remarkable thermal stability, which significantly enhances the electrochemistry and safety of LIBs. First, this paper reviewed recent research hotspots and processes of electrospun PVDF-based LIB separators; then, their pivotal parameters influencing morphology, structures, and properties of separators, especially in the process of electrospinning solution preparation, electrospinning process, and post-treatment methods were summarized. Finally, the challenges of PVDF-based LIB separators were proposed and discussed, which paved the way for the application of electrospun PVDF-based separators in LIBs and the development of LIBs with high electrochemistry and security.

A Novel Upside-Down Thermal Annealing Method Toward High-Quality Active Layers Enables Organic Solar Cells with Efficiency Approaching 20.

The emerging non-fullerene acceptors with low voltage losses have pushed the power conversion efficiency of organic solar cells (OSCs) to ≈20% with auxiliary morphology optimization. Thermal annealing (TA), as the most widely adopted post-treatment method, has been playing an essential role in realizing the potential of various material systems. However, the procedure of TA, i.e., the way that TA is performed, is almost identical among thousands of OSC papers since ≈30 years ago other than changes in temperature and annealing time. Herein, a reverse thermal annealing (RTA) technique is developed, which can enhance the dielectric constant of active layer film, thereby producing a smaller Coulomb capture radius (14.93 nm), meanwhile, forming a moderate nano-scale phase aggregation and a more favorable face-on molecular stacking orientation. Thus, this method can reduce the decline in open circuit voltage of the conventional TA method by achieving decreased radiative (0.334 eV) and non-radiative (0.215 eV) recombination loss. The power conversion efficiency of the RTA PM6:L8-BO-X device increases to 19.91% (certified 19.42%) compared to the TA device (18.98%). It is shown that this method exhibits a superb universality in 4 other material systems, revealing its dramatic potential to be employed in a wide range of OSCs.

Decylammonium sulfate post-treatment for efficient hole-conductor-free printable perovskite solar cells with reduced voltage loss

Hole-conductor-free printable mesoscopic perovskite solar cells (p-MPSCs) have attracted widespread attention for their low cost, up-scalability, and exceptional stability. However, the high defect density of perovskite and the absence of interfacial barrier layer between perovskite and carbon electrode cause profound open-circuit voltage (VOC) loss, which results in uncompetitive power conversion efficiency (PCE). Herein, an anion-cation synergy of decylammonium sulfate (DA2SO4) is utilized for suppressing VOC loss of p-MPSCs via a facile post-treatment method. DA+ cations transform the perovskite adjacent to carbon electrode into wide-bandgap 2D perovskite for blocking electrons, while the SO42− anions interact with undercoordinated lead centers for reducing defect density. As a result, the modified device delivers an enhanced PCE from 17.78% to 19.59%, with an improved VOC from 0.98 V to 1.06 V. Meanwhile, the modified device without any encapsulation exhibits excellent moisture stability with the PCE remained almost 99% of the initial value after 528 h aging in 75% RH air at room temperature.

Enhanced charge carrier transport and defects mitigation of passivation layer for efficient perovskite solar cells

Surface passivation has been developed as an effective strategy to reduce trap-state density and suppress non-radiation recombination process in perovskite solar cells. However, passivation agents usually own poor conductivity and hold negative impact on the charge carrier transport in device. Here, we report a binary and synergistical post-treatment method by blending 4-tert-butyl-benzylammonium iodide with phenylpropylammonium iodide and spin-coating on perovskite surface to form passivation layer. The binary and synergistical post-treated films show enhanced crystallinity and improved molecular packing as well as better energy band alignment, benefiting for the hole extraction and transfer. Moreover, the surface defects are further passivated compared with unary passivation. Based on the strategy, a record-certified quasi-steady power conversion efficiency of 26.0% perovskite solar cells is achieved. The devices could maintain 81% of initial efficiency after 450 h maximum power point tracking.

Preparation of Stainless Steel Superhydrophobic Surface and Analysis of Hydrophobic Mechanism.

By analyzing the application conditions of hydrothermal oxidation equipment, we found that the corrosion resistance of stainless steel is crucial. It is necessary to prepare superhydrophobic surface to improve the corrosion resistance and find a cost-effective and environmentally friendly preparation method. Therefore, this paper proposes a method combining nanosecond laser and post-treatment, which uses nanosecond laser to etch microstructure and reduces the surface energy through diverse post-treatment methods to achieve hydrophobicity. The surface morphology characteristics were studied, the wettability of various post-treatment methods was compared, and the hydrophobic mechanism was analyzed. The results show that the groove width has a significant impact on the surface morphology. Superhydrophobic surface can be obtained immediately after heat treatment and fluorosilane modification, while natural storage requires more than one month. All of the post-treatment can obtain hydrophobicity by reducing the surface energy, but the chemical composition is distinct. The cost-effective composite process of laser and heat treatment plays a guiding role in future research on the preparation of stainless steel superhydrophobic surface and has broad prospects in the future in large-scale production and application.

Highly efficient removal of ozone on amorphous manganese oxides modified by alkali metals

Low stability deriving from the accumulation of moisture and intermediates represents the major challenge for practical applications of manganese oxides (MnOx) for ozone elimination. Here, Li+, Na+ and K+ were successfully introduced into the channel framework of amorphous MnOx to improve its stability through a simple post-treatment method. Alkali metal modification can promote the removal of ozone by amorphous MnOx, and Na-MnOx exhibited superior catalytic activity and remarkable stability in water-resistance, cycling and long-term tests. The Na introduction facilitated the formation of oxygen vacancies, and improved low-temperature reducibility and lattice oxygen mobility. The mechanism of ozone decomposition on amorphous MnOx and Na-MnOx catalysts was deeply investigated by in situ diffuse reflectance infrared Fourier transform spectra (in-situ DRIFTS). The Na addition strengthened the hydrophobicity of oxygen vacancies, but also greatly boosted the desorption of intermediate oxygen species and the ozone decomposition cycle.

Advances in the Fabrication, Properties, and Applications of Electrospun PEDOT-Based Conductive Nanofibers.

The production of nanofibers has become a significant area of research due to their unique properties and diverse applications in various fields, such as biomedicine, textiles, energy, and environmental science. Electrospinning, a versatile and scalable technique, has gained considerable attention for its ability to fabricate nanofibers with tailored properties. Among the wide array of conductive polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) has emerged as a promising material due to its exceptional conductivity, environmental stability, and ease of synthesis. The electrospinning of PEDOT-based nanofibers offers tunable electrical and optical properties, making them suitable for applications in organic electronics, energy storage, biomedicine, and wearable technology. This review, with its comprehensive exploration of the fabrication, properties, and applications of PEDOT nanofibers produced via electrospinning, provides a wealth of knowledge and insights into leveraging the full potential of PEDOT nanofibers in next-generation electronic and functional devices by examining recent advancements in the synthesis, functionalization, and post-treatment methods of PEDOT nanofibers. Furthermore, the review identifies current challenges, future directions, and potential strategies to address scalability, reproducibility, stability, and integration into practical devices, offering a comprehensive resource on conductive nanofibers.

Antiviral Activity of Graphene Oxide-Silver Nanocomposites Against Murine Betacoronavirus.

The high infectivity of coronaviruses has led to increased interest in developing new strategies to prevent virus spread. Silver nanoparticles (AgNPs) and graphene oxide (GO) have attracted much attention in the antiviral field. We investigated the potential antiviral activity of GO and AgNPs combined in the nanocomposite GO-Ag against murine betacoronavirus MHV using an in vitro model. GO, AgNPs, and GO-Ag characterization (size distribution, zeta potential, TEM visualization, FT-IR, and EDX analysis) and XTT assay were performed. The antiviral activity of GO-Ag nanocomposites was evaluated by RT-qPCR and TCID50 assays. The results were compared with free AgNPs and pure GO. Cell growth and morphology of MHV-infected hepatocytes treated with GO-Ag composites were analyzed by JuLI™Br. Immunofluorescence was used to visualize the cell receptor used by MHV. Ultrastructural SEM analysis was performed to examine cell morphology after MHV infection and GO-Ag composite treatment. A significant reduction in virus titer was observed for all nanocomposites tested, ranging from 3.2 to 7.3 log10 TCID50. The highest titer reduction was obtained for GO 5 µg/mL - Ag 25 µg/mL in the post-treatment method. These results were confirmed by RT-qPCR analysis. The results indicate that GO-Ag nanocomposites exhibited better antiviral activity compared to AgNPs and GO. Moreover, the attachment of AgNPs to the GO flake platform reduced their cytotoxicity. In addition, the GO-Ag composite modulates the distribution of the Ceacam1 cell receptor and can modulate cell morphology. Graphene oxide sheets act as a stabilizing agent, inhibiting the accumulation of AgNPs and reducing their cellular toxicity. The GO-Ag composite can physically bind and inhibit murine betacoronavirus from entering cells. Furthermore, the constant presence of GO-Ag can inhibit MHV replication and significantly limit its extracellular release. In conclusion, GO-Ag shows promise as an antiviral coating on solid surfaces to minimize virus transmission and spread.

Supplementary treatment of FDM printed parts. Review

The application of additive technologies to the manufacture of polymer and composite products is now actively expanding. The FDM printing process is popular because of its ability to adapt to specific tasks and to bring products with complex geometries into production quickly and at minimal cost, and is seen as a technology that can compete with injection molding. However, due to the nature of the process, FDM printed parts are significantly inferior in quality to injection molded parts. Much attention is now being paid to research into supplementary treatment methods to improve the properties of FDM printing parts. However, there is no complete and clear description of such methods, nor are there any recommendations on the choice of treatment methods aimed at improving the specific parts properties. The aim of this review is to analyse the research in the field of post-treatment of parts in order to systematise their advantages and limitations, which will allow a more reasoned choice of a post-treatment method to improve specific properties of FDM printing parts. <br> The bibliography includes 120 references.

Polyvinylidene fluoride-alkali lignin blend: A new candidate for membranes development

New blend membranes consisting of a tuned ratio of polyvinylidene fluoride (PVDF) and alkali lignin (AL) were studied. Through the use of a green solvent like dimethyl sulfoxide, effective mixing between PVDF and AL was achieved, leading to the development of highly hydrophilic membranes with robust mechanical stability. Characterization methods confirmed the suitability of the blend for membrane preparation and its hydrophilic nature.A key aspect of the strategy involved hydrophilizing PVDF during the preparation process by blending it with AL in the pot. This approach aimed to streamline production by reducing the number of steps compared to post-treatment methods such as grafting or coating. The presence of hydrophobic/hydrophilic groups in the AL structure addressed the challenge of compatibility between PVDF and conventional hydrophilic polymers, enhancing interaction between the components.The resulting hydrophilic material exhibited improved pure water permeance and demonstrated resistance to irreversible fouling. The membrane's ability to process wastewater streams and its resistance to fouling was demonstrated by separating stable and uniform submicron oil-in-water emulsions with high rejection (>99.9 %) up to a volume reduction factor (VRF) of 7.7.

Effect of SiO2-reinforcement and alkali treatment on the corrosion resistance of plasma electrolytic oxide coating on AZ31 magnesium alloy

Plasma electrolytic oxidation (PEO) produces an oxide coating containing pores and cracks lowering corrosion protection. The defects can be sealed by in-situ or post-treatment methods. This work compares the sealing effect of SiO2 particles and post-alkali treatment on the corrosion resistance of PEO coatings formed on AZ31 magnesium (Mg) alloy. PEO was conducted in a phosphate-based electrolyte containing 2 g/l nanoparticle SiO2 at a constant current density of 300 A/m2 for 10 min. The post-alkali treatment was performed in 0.5 M NaOH solution at 80 °C for 30 min. The corrosion resistance was evaluated using polarization, electrochemical impedance spectroscopy, and weight loss tests. The SiO2 particles were successfully embedded uniformly in the Mg3(PO4)2 coating, enhancing the coating compactness and stability. The reinforced coating exhibited ten times higher impedance modulus and lower corrosion current density. The post-alkali treatment improved corrosion resistance but not as high as the SiO2 reinforcement. The impedance modulus of the alkali-treated specimen increased five times, and the corrosion current density decreased three times of the base coating. The weight loss test consistently showed that the SiO2-reinforced coating generated lower mass loss during 14 days of immersion in simulated body fluid.

High performance and stability of perovskite solar cells achieved through anti-solvent modulation of multi-orientation PbI2 and stress relief

The morphology of the pre-deposited PbI2 layer plays a crucial role in determining the quality of perovskite films in sequentially deposited perovskite solar cells. The main reason is that the PbI2 film is too dense, which makes it difficult for organic salts to fully enter and react with them. This work presents a novel solvent extraction post-treatment method for the construction of bilayer PbI2 films. The PCE of the prepared champion device reaches 23.8 %, which is higher than 21.6 % of the control device. We observed that the perovskite solar cells treated with EA retained over 90 % of their initial efficiency after being stored for approximately 700 h in a nitrogen atmosphere, and over 80 % in air, demonstrating superior stability compared to the control group.