Surface Chemical Analysis Research Articles

LiTFSI salt concentration effect for well‐balanced ion transport and physical properties in nanocellulose‐reinforced PEO#600 solid electrolytes

AbstractPoly(ethylene oxide) (PEO) with an oxygen group serves as a reactive site for the pathway of lithium‐ion transport. Reducing the PEO crystal domain in solid electrolytes is an extremely efficient approach for enhancing the mobility of ions. The present study applied various EO/Li molar ratios to modify the physical and electrochemical properties of PEO nanocomposite reinforced by nanocellulose. An elevated lithium salt concentration causes a gradual decline in crystallinity and mechanical strength. The electrochemical performance of the 13 EO/Li molar ratio voltammogram and charge–discharge shows efficient Li‐ion transport with 5.6 × 10−4 S/cm conductivity at room temperature and 131 mA h g−1 initial discharge capacity. The shifting glass transition and melting point at lower temperatures (−40.5 to −44.5°C and 45.3–43.8°C) suggest greater ion mobility throughout the large non‐crystalline structure. Lithium ions are limited by membrane weakening and re‐crystallization caused by high lithium salt (EM_11) concentrations. EM_13 has the highest specific capacity, operating voltage, and lithium transfer number depends on balanced electrochemical performance and physical features. XPS surface chemistry analysis explains LiF, Li2CO3, and Li2O solid electrolyte interfaces (SEI) in EM samples. A lower Li2O (11.62 at.%) than LiF (38.4 at.%) after cycling enhances Li‐ion diffusion and cell reversibility.

3D printing of biodegradable biocomposites based on forest industrial residues by fused deposition modeling

This study investigated the impact of industrial forest residues (IFR) type and proportion on 3D-printed biocomposites (BC). Fused deposition modeling (FDM) produced BC containing up to 20 % Jack pine sawdust, wood ashes, cellulose fibers, and polylactic acid (PLA). The BC thermal stability, surface chemistry, microstructure, and physical and mechanical were investigated. Thermal stability investigations revealed that adding IRF resulted in a decline in the PLA degradation temperature, an increase in the residual mass, a decrease in the glass transition temperature, and an improvement in crystallinity. Add IRF to PLA showed an important reduction in ductility, a consistent reduction of the tensile and flexural strengths with increasing proportion but only a slight or a non-significant reduction the modulus of elasticity. Adding forest waste filler to pure PLA increased the water absorption (WA) and dimensional accuracy (TA) of the biocomposites, which was expected due to the hydrophilic character of fillers. The microstructural analysis demonstrated that a higher filler level resulted in a greater porosity, roughness, and visible filler pull-out on the filament and printed parts surfaces. Surface chemistry analysis suggested poor interactions between the PLA and the fillers and consequently poor interfacial adhesion. Furthermore, the rheological investigations confirmed that the complex viscosity and storage modulus of PLA-Jack pine's sawdust and PLA-cellulose fibers increased with filler. In contrast, the PLA-wood ashes showed opposite results. Using 3D-printed biodegradable biocomposites provided a sustainable option for reducing dependence on non-renewable plastic, valorizing the value chain of forest products, and promoting the circular economy.

Underwater in-situ plasma treatment of coarse wool fibers for scouring and bleaching

Wool, in its natural state, is laden with impurities such as grease, suint, dust, and vegetable matter on its surface, necessitating their removal for the wool to be suitable for various products. Traditional scouring methods involve the extensive use of water, detergents, and chemicals, leading to the generation of hazardous wastewater. Moreover, coarse fibers often require bleaching due to the retention of natural pigments during the scouring process. This study introduces an innovative and environmentally friendly plasma treatment for scouring and bleaching of the coarse wool fibers, referred here after as underwater in-situ plasma treatment (UIPT), which is entirely free from chemicals and detergents. Research includes a comparative analysis of UIPT, plasma-activated water (PAW), normal water (NW) and conventional wet-chemical process (CWP) for wool fiber scouring and bleaching. Surface morphology and surface chemistry analyses underscore the efficacy of UIPT in cleaning the coarse wool. The residual grease analysis demonstrated a substantial reduction in grease content of raw wool from 20% to 2% after plasma treatment, while the whiteness index of wool fibers increased from 48% to 70%.

Ensuring the Global Comparability of XPS Data Through Intensity Scale Calibration: Summary of ISO 5861:2024

ABSTRACTFor quantitative analyses of data acquired from x‐ray photoelectron spectroscopy (XPS) instruments to be globally comparable across industry and academia, a consistent and traceable intensity calibration method is required. ISO 5861 was prepared by Technical Committee ISO/TC 201 Surface Chemical Analysis, Subcommittee 7, Electron Spectroscopies, and describes an intensity calibration method for x‐ray photoelectron spectrometers that use quartz‐crystal monochromated Al Ka x‐rays. The method employs low‐density polyethylene reference spectra that are corrected for any instrument geometry and are traceable to the true reference spectra for gold, silver and copper held by the National Physical Laboratory (NPL), UK. This international standard generates a spectrometer relative response function for use in quantitative XPS analysis that is consistent with NPL's intensity calibration method to within 5% relative error.

Evaluation of Oxide|Sulfide Heteroionic Interface Stability for Developing Solid-State Batteries with a Lithium-Metal Electrode: The Case of LLZO|Li6PS5Cl and LLZO|Li7P3S11.

Developing solid-state batteries (SSB) with a lithium metal electrode (LME) using only one type of solid electrolyte (SE) is a significant challenge since no SE fits all the requirements imposed by both electrodes. A possible solution is using multilayer SSBs with an LME where the drawbacks of each SE are overcome by using layers of different SEs. However, research on inorganic SE1|SE2 heteroionic interfaces is still quite preliminary, especially regarding oxide|sulfide heteroionic interfaces. This work reports the electrochemical investigation of the heteroionic interface between Li6.25Al0.25La3Zr2O12 (Al-LLZO) and two representative materials for sulfide-based SEs: argyrodite-based Li6PS5Cl (LPSCl) and glass-like Li7P3S11 (LPS711). Through in-depth temperature- and pressure-dependent impedance analyses of multilayer symmetric cells at equilibrium (i.e., no current load), the electrical properties of the heteroionic interfaces are assessed. The pressure-dependent kinetic of the Al-LLZO|LPSCl pair is interpreted with the concept of geometric constriction resistance and show that its resistance is lower than for the Al-LLZO|LPS711 pair. Furthermore, the effect of Al-LLZO surface treatment on the electrical properties of the Al-LLZO|LPSCl heteroionic interface is evaluated. Such investigation shows that the value of the interface activation energy decreases when the Al-LLZO surface is heat treated, revealing a significant influence of the carbonate/hydroxide passivation layer on the heteroionic interface. Additionally, by cycling the symmetric cell for 900 h at 1.0 mAh·cm-2, it is revealed that the Al-LLZO|LPSCl interface has a lower impedance increase than the Al-LLZO|LPS711 interface, especially if the Al-LLZO is heat treated. With this work, we highlight that the oxide|argyrodite combination can be a promising candidate for multilayer SSBs with an LME. However, we show that an optimized LLZO surface treatment and chemical analysis of the interface are recommended for future research.

Experimental study on corrosion inhibition of mild steel using Mukia maderaspatana leaves extract as green inhibitor

In this work, investigations were conducted into the adsorption behaviour and inhibitory effect of Mukia maderaspatana leaves extract on the corrosion of mild steel in 1.5M HCl solution at several temperatures. The techniques included chemical methods (weight loss measurements), surface analysis (SEM, FESEM) and solution analysis (UV–visible spectrophotometric, ICP-MS) techniques. The examination of the data revealed that the efficiency of inhibition rose as the inhibitor's concentration increased and fell as the temperature increased. At 30 degrees Celsius, the concentration of inhibitor resulted in an increase in corrosion inhibition efficiency, reaching 99.02% efficiency at 8% concentration. The physical adsorption of the inhibitor on the metal surface was demonstrated by the adsorption free energy of the plant extract on mild steel. The conclusions above are supported by data from examinations of Scanning Electron Microscopy, FESEM, UV–visible and Fourier transform infrared spectrophotometry.

Surface preparation by femtosecond laser - An adhesion strength perspective for suspension plasma sprayed ceramic coatings

Surface preparation is very important for the adhesion of thermal sprayed coatings. In this work, the effect of surface preparation on the adhesion strength of suspension plasma sprayed (SPS) Al2O3 coatings is investigated. Aluminum (Al-2024) substrates were micromachined by femtosecond laser (FSL) and also mechanically blasted by conventional grit blasting for surface preparation prior to SPS coating. Surface morphology results showed laser-induced periodic surface structures (LIPSS) produced by FSL, whereas grit blasting produced random irregularities with peaks and undercuts. Surface chemistry analysis showed that the FSL-prepared substrates were functionalized by -OH and O, while the grit-blasted substrates were not functionalized. The prepared substrates were coated by the SPS process under two spray conditions, where one condition was selected to produce a dense coating and the other condition was selected to produce a porous coating. The dense coating showed poor adhesion regardless of surface preparation, while the porous coating showed good adhesion for both grit-blasted and FSL-treated substrates. The adhesion strength of the porous coating was evaluated using the ASTM C-633 pull test protocol. A significant improvement (4.5 factors higher) in adhesion strength was achieved for the FSL-prepared substrates compared to the grit-blasted substrates. The improved adhesion of the FSL-prepared substrates was assessed by surface chemistry and surface morphology analyses of the prepared substrates, as well as by further analysis of the failed samples after the adhesion test and splat analysis. Results from this research showed that FSL has potential as an effective surface preparation technique for SPS.

Hyperbranched Poly-l-Lysine Modified Titanium Surface With Enhanced Osseointegration, Bacteriostasis, and Anti-Inflammatory Properties for Implant Application: AnExperimental InVivo Study.

This study aimed to explore multiple effects of hyperbranched poly-l-lysine (HBPL) titanium (Ti) surfaces on osseointegration, bacteriostasis, and anti-inflammation across three different animal models. Ti surfaces were covalently modified with HBPL, with uncoated surfaces as controls. Characterization included scanning electron microscopy (SEM) and surface chemistry and elemental analysis (EDX). Ti and Ti-HBPL implants were placed in conventional canine edentulous sites, post-operative infection canine edentulous sites, and diabetic rat tibias. Implants from canine edentulous models were analyzed using micro-CT and histomorphometry to assess osseointegration at 8 weeks. Post-operative infection beagles were used to evaluate antibacterial efficacy through clinical parameters and bacterial cultures at 1 week. In diabetic rats, micro-CT and histomorphometry were performed at 8 weeks. HBPL was uniformly grafted on Ti-HBPL surfaces. Ti-HBPL surfaces showed higher bone volume/total volume (BV/TV, p < 0.001), bone-implant contact (BIC%, p < 0.001), and trabecular number (Tb.N, p < 0.01) in beagles. Besides, it displayed higher BIC% (p < 0.001) and bone area fraction occupancy (BAFO%, p < 0.01) in hard tissue sections. In an infected model, Ti-HBPL surfaces exhibited lower bleeding on probing (BOP, p < 0.001), and plaque index (DI, p < 0.01), with reduced bacterial colony formation (p < 0.001) compared to the control group. In diabetic rats, Ti-HBPL surfaces showed an increase in BV/TV (p < 0.01) and Tb.N (p < 0.001), downregulated TNF-α and IL-1β (p < 0.01), and upregulated IL-10 (p < 0.01) and osteocalcin (OCN) expression (p < 0.01). HBPL-Ti surfaces demonstrated enhanced osseointegration, bacteriostasis, and anti-inflammatory effects invivo.

Enhancing reliability in oxide-based memristors using two-dimensional transition metal dichalcogenides

Oxide-based memristor is an attractive candidate for future nonvolatile resistive random access memory (RRAM) devices. However, it suffers from insufficient reliability, owing to the randomness of the conductive filaments, hindering the practical use of the memristor for future RRAM applications. Here, we propose harnessing the two-dimensional (2D) transition metal dichalcogenides (TMDs) on oxide memristor to achieve high device reliability by controlling oxygen vacancy-based filaments near the TMDs/oxide interface. By forming the Pt/WSe2/HfxZr1-xO2 (HZO)/TiN structure, the fabricated memristor exhibits high reliability with good cyclic endurance (over 2,000 cycles), retention (104 s), and low cycle-to-cycle variability. Surface chemical analysis reveals the abundant oxygen vacancies induced by forming WSe2/HZO interface are the source of filamentary switching. By incorporating 2D materials and oxides, the practical application of memristor to future information processing devices can be boosted by the enhanced device reliability.

Designing electrolytes for enhancing stability and performance of lithium-ion capacitors at large-scale cylindrical cells

This study investigates the impact of fluorinated ethylene carbonate (FEC) as a co-solvent in the electrolytes of large-scale lithium-ion capacitors (LICs), an area previously unexplored. Our comprehensive analysis integrates electrochemical analysis, gas detection, and surface chemical examination to assess the performance and stability of a 1.2 M LiPF6 electrolyte system. We explored various formulations, including a standard EC/EMC/DEC mixed solvent and newly designed electrolytes with FEC additions, such as EC/EMC/DEC/FEC and DMC/FEC blends. Our findings demonstrate that the DMC/FEC blend matches and even surpasses the capacity retention of traditional electrolytes, suggesting enhanced long-term stability. FEC's presence significantly reduces electrolyte decomposition, as confirmed by in situ Differential Electrochemical Mass Spectrometry and ex-situ gas chromatography. Further, surface chemical analysis highlighted the formation of a stable, LiF-rich solid electrolyte interface (SEI) when FEC is included, thereby improving the chemical stability of the system. These results underline FEC's crucial role in optimizing electrolyte compositions, thus advancing the development of more efficient and durable LIC systems. FEC's integration into LIC electrolytes represents a significant breakthrough, enhancing overall performance and longevity, with broad implications for the application of LICs in various technologies.

Optimal Hydrofluoric Acid Etching Duration and Impact of Silane/Adhesive on Profilometric Properties and Bonding to Lithium Disilicate Glass Ceramics.

This study aimed to assess the surface roughness, surface free energy (SFE), and shear bond strength (SBS) on a lithium disilicate glass-ceramic surface following varying etching protocols (time variation) and application of silane either with or without adhesive material. Lithium disilicate glassceramic (LDGC) computer-aided design and computer-aided manufacture (CAD/CAM) blocks were cut using a slow-speed cutting mechanism. CAD/CAM blocks were then evaluated for surface roughness, 6 groups (n=20); SFE,12 groups (n=5); and SBS, 10 groups (n=10). The cut CAD/CAM blocks were randomly allocated to 28 groups. Groups were based on the following: 30 or 90 seconds of etching with 9% hydrofluoric acid (HF); application or absence of silane coupling agent (Sil); and application or absence of adhesive (Adh).The control group (Cont) had untreated surfaces. Unetched surfaces were surveyed with only silane (Sil), only adhesive (Adh), or silane+adhesive (SilAdh). Further etched groups were HF30 with HF for 30 seconds, HF30-Sil, HF30-Adh, and HF30-SilAdh. Alternative 90-second etching times produced similar groups: HF90, HF90-Sil, HF90-Adh, and HF90-SilAdh. A digital profilometer was used to assess the surface roughness of specimens, and two readings were recorded. Sessile drop analysis was used to examine SFE specimens, and the OWRK model was modified to measure liquid surface tension. A universal testing machine (UltraTester, Ultradent Products, Inc, South Jordan, UT, USA) was utilized for the SBS test, with the crosshead speed set at 0.5 mm/min until failure. Representative treated specimens from each group were submitted to surface morphological evaluation and chemical analysis using scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDXS) (n=3). After data collection, evaluation using one- or two-way analysis of variance and the post-hoc Tukey test (α=5%) was conducted. A longer etching time of 90 seconds produced a rougher surface. After the 90-second etching process, SFE displayed the greatest values; nevertheless, the use of silane did not affect SFE. For every group examined, the application of silane followed by adhesive resulted in an increase in SBS and more stable bonding over time. SEM/EDXS showed that etching times did affect the amount of cerium on the surface and altered surface morphology. Higher and more consistent bond strengths have been observed with longer etching periods. Silane and adhesive application on the ceramic surface showed stronger and enhanced bond strength, specifically when longer etching times were employed.

Surface morphology and chemical composition analysis of titanium dental implants using SEM and EDX.

The chemical content and surface morphology of titanium implants have a greater impact on the osseointegration characteristic of dental implants. Therefore this study was done to examine the surface morphology and chemical composition of commercially available titanium dental implants. (BioLine Dental Implants Series-single piece (A) and spiral implants (B)). The chemical composition was determined by the Energy Dispersive X-ray Spectroscopy (EDX) method and the surface morphology was performed by Scanning Electron Microscopy (SEM) method. The results for chemical composition of titanium implants using EDX method revealed that titanium (Ti) constitutes the major surface components on the plain and top land area of the single piece compressive implants which is 89.71 weight% and 71.55 weight % respectively. Iron (Fe)-66.60 weight % is considered as major element along with chromium (Cr)-18.34 weight %on the plain area of spiral implants and O (19.90 weight %) and Al (12.43 weight %) on the top land area of spiral implants. The surface morphology and impact of the manufacturing process on the implant surface using SEM method revealed that the similar surface irregularities with diameter ranging from 10 µm to 20 µm on the side view of the top land area and diameter of 10 µm on the side view of plain area for both the samples. Sample A showed some amorphous structures with grainy marks on the apical view whereas Sample B showed heavy grinding and shear marks on the apical view at diameter ranging from 10 µm to 20µm.

Optical properties of Makrofol under various alpha fluences

The optical properties of Makrofol samples are investigated under various fluences of alpha exposure (2 MeV at 5×102, 103, 5×103, 104 , 5×104, 105, 5×105 and 106 alphas.cm2 alongside the unirradiated ones (pristine). Several analyses, including UV–visible, diffused reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared/attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, are carried out to reveal the subsequent variations in the optical features of the irradiated polymer foils. The optical transmittance of the irradiated samples notably increases against the pristine ones, while it undergoes a+ plateau over various fluences. Additionally, the scattering events are more prominent in pristine samples over UV (240–400 nm) and IR (900–1040 nm) compared to the irradiated ones. While there are negligible physical alterations on the polymer surface, the photoluminescence emission gradually decreases with increasing alpha fluences in the irradiated samples mainly due to the reduction in the population of the aromatic rings. The latter is also verified by means of the surface chemical analyses such as XPS, FTIR-ATR and sessile drop/contact angle measurements. XPS reveals that the alpha particles give rise to the successive scissions of C–C and CO bonds and the consequent recombination events in the form of C–O bonds, evidenced by the changes in their abundance percentages. Concurrently, the surface hydrophilicity initially elevates up to a certain fluence and then reduces at higher fluences, indicating a couple of competitive mechanisms are involved in the context of the interactions of the alpha particles with the Makrofol polycarbonate (PC).

Application of external voltage-applied enhances surface adhesion of Shewanella oneidensis MR-1

Electroactive bacteria play a crucial role in electrocatalytic oxidation and reduction reactions within bioelectrochemical systems (BES). However, the influence of BES startup modes on the adhesion of electroactive bacteria and the underlying mechanisms remains elusive. We hypothesize that startup mode-induced microniches trigger changes in bacterial motility, which mediate bacterial adhesion on anodic surface. To test this hypothesis, we employed Shewanella oneidensis MR-1 as a model strain and launched investigations in single-chambered BES under both external voltage-free (EVF) and external voltage-applied (EVA) modes. Our results showed that the EVA mode facilitated MR-1 adhesion up to fourfold compared to the EVF mode. Surface chemistry analysis revealed that EVA mode, with proper external voltages (400–600 mV), enhanced substrate adsorption onto anodic surfaces by up to 410 %, significantly promoting bacterial cell movement and chemotactic migration towards anodic surfaces, thereby facilitating bacterial adhesion. Principal component analysis and structural equation modeling indicated that lactate adsorption capacity was the determining factor for bacterial adhesion under EVF mode, whereas external voltage diminished the effect of lactate on triggering cell motility and subsequent bacterial adhesion in the EVA mode. Our findings provide valuable insights into the initiation and enhancement of electrochemically active biofilm on electrode surfaces in BES.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

BackgroundMembrane preparation and membrane modification processes have long involved the use of toxic solvents. The present work proposes to only use envrionmentally-friendly solvents for both the fabrication and the surface modification of hydrophobic microfiltration membranes. In addition, coating processes for membrane modification are essentially surface modification processes. However, spray-coating may be a suitable method for both surface and bulk modification. MethodsAfter dissolving poly(vinylidene fluoride) in dimethylsulfoxide, membranes were formed by the vapor-induced phase separation process, and then modified using an aqeous solution of an amphiphilic copolymer containing poly(ethylene glycol) methyl ether methacrylate units. Then, a variety of physicochemical techniques were employed to characterize the membrane structure and prove the effectiveness of the surface/bulk modification. Antifouling tests in static and dynamic conditions were conducted. Significant findingsIt is possible to reduce the water contact angle of the top surface of the membrane from 135° to 0° and that of the bottom surface from 126° to 0° within <10 s, indicating successful hydrophilization of the membrane on the one hand, and top-to-bottom modification, despite solely exposing the top surface to the spray, on the other hand. This conclusion was confirmed by deidcated surface chemistry analyses. Besides, the membranes maintained their original highly porous and symmetric structure with light effects on surface porosity and pore size following the spray-coating process. The drasting improvement of hydrophilicity resulted in effective mitigation of fibrinogen adsorption (reduced by 85 %) and Escherichia coli adhesion (reduced by 86 %). Fouling during cyclic filtration involving a bacterial suspension was also effectively reduced with a flux recovery ratio of 53 % (against 37 % for a commercial hydrophilic membrane) and an irreversible flux decline ratio of 47 % (against 63 % for a commercial hydrophilic membrane) in the conditions of the test.

Predicting Sodium-Ion Battery Performance through Surface Chemistry Analysis and Textural Properties of Functionalized Hard Carbons Using AI.

Traditionally, the performance of sodium-ion batteries has been predicted based on a single characteristic of the electrodes and its relationship to specific capacity increase. However, recent studies have shown that this hypothesis is incorrect because their performance depends on multiple physical and chemical variables. Due to the above, the present communication shows machine learning as an innovative strategy to predict the performance of functionalized hard carbon anodes prepared from grapefruit peels. In this sense, a three-layer feed-forward Artificial Neural Network (ANN) was designed. The inputs used to feed the ANN were the physicochemical characteristics of the materials, which consisted of mercury intrusion porosimetry data (SHg and average pore), elemental analysis (C, H, N, S), ID/IG ratio obtained from RAMAN studies, and X-ray photoemission spectroscopy data of the C1s, N1s, and O1s regions. In addition, two more inputs were added: the cycle number and the applied C-rate. The ANN architecture consisted of a first hidden layer with a sigmoid transfer function and a second layer with a log-sigmoid transfer function. Finally, a sigmoid transfer function was used in the output layer. Each layer had 10 neurons. The training algorithm used was Bayesian regularization. The results show that the proposed ANN correctly predicts (R2 > 0.99) the performance of all materials. The proposed strategy provides critical insights into the variables that must be controlled during material synthesis to optimize the process and accelerate progress in developing tailored materials.

Fabrication and Characterization of Silicon Dioxide-Reinforced Polydimethylsiloxane Composite Coating for Corrosion Protection of Galvanized Iron

&lt;div&gt;The present work highlights the significance of nanocomposite coatings for their ease of processing and applicability in combating corrosion. Ongoing research is dedicated to the development of an effective nanocomposite hydrophobic coating. A hydrophobic nanocomposite coating was deposited on galvanized iron (GI) using a sol-gel route with polymethylsiloxane (PDMS) reinforced with nano-SiO&lt;sub&gt;2&lt;/sub&gt;. Surface morphology and chemical composition analysis, conducted with scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR), revealed the coating’s structural and compositional attributes. The resulting hydrophobic coating exhibits a water contact angle (WCA) of 104.1°, indicating a 30.45% increase compared to bare GI. Subsequent to these characterizations, the adhesion of the coated GI, rated as 4B per ASTM D3359, is followed by commendable resistance to corrosion, as evidenced by electrochemical tests. The corrosion rate for the coated GI sheet is notably low, at 62.78 × 10&lt;sup&gt;−3&lt;/sup&gt; mpy, underscoring its anti-corrosive efficacy.&lt;/div&gt;

Effect of Chlorhexidine and Povidone-iodine Mouth Rinses on Corrosion Resistance and Surface Characteristics of Stainless Steel Orthodontic Brackets – An in vitro and in vivo Study

Abstract Background: Stainless steel (SS) orthodontic brackets may have varying corrosion resistance when used with mouthwashes during orthodontic treatment. Studying their effects on orthodontic brackets will be beneficial. Aim: The study’s objective was to analyze the surface characteristics of SS orthodontic brackets and their resistance to corrosion, exposed to chlorhexidine and povidone-iodine mouth rinses – an in vitro and in vivo study. Materials and Methods: The in vitro test: MBT 0.022” slot SS orthodontic brackets were immersed in three groups – Group A – Modified Meyer-Fusayama artificial saliva (AS), Group B – Chlorhexidine, and Group C – Povidone-iodine mouthwash. The in vivo test: Brackets were conventionally bonded on the patient’s teeth and divided into Group I – control group, Group II – patients used chlorhexidine, and Group III used povidone-iodine mouth rinse. The corrosion resistance and surface characteristics of SS brackets were determined using scanning electron microscope (SEM), electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. Results: Higher corrosion resistance was obtained for brackets immersed in chlorhexidine mouth rinse. The polarization resistance value of the orthodontic SS bracket was 109 MΩ, 1383 MΩ, and 769 MΩ immersed in AS, chlorhexidine, and povidone-iodine mouth rinse, respectively. After surface chemical analysis, XPS data showed the largest intensity peak of metallic chromium (CrO) fresh sample and in the sample immersed in chlorhexidine mouthwash. According to SEM, brackets immersed in chlorhexidine showed a relatively smooth surface. Conclusion: In this study, chlorhexidine was found to be less corrosive followed by povidone-iodine.

EVALUATION OF THE EFFECT OF AIR ON THE HYDRATION SYSTEM OF THE AXIAL PISTONS

This study investigates the effect of air exposure on the hydration system of axial pistons, critical components in various hydraulic systems. The hydration process, which is integral to the functionality and longevity of axial pistons, is potentially sensitive to environmental factors such as air. This research aims to elucidate the effect of air on the hydration kinetics, surface properties and performance of axial pistons. Experimental studies were conducted using controlled environments to analyze the hydration behavior of piston samples under varying degrees of air exposure. Techniques such as surface microscopy, chemical analysis and mechanical testing were used to comprehensively evaluate the effects. Preliminary findings indicate that exposure to air significantly affects the hydration kinetics of axial pistons, affecting the rate and extent of hydration. Surface analysis reveals changes in surface morphology and chemical composition indicating changes in the air-induced hydration process. Moreover, mechanical testing reveals notable differences in the performance characteristics, including wear resistance and friction properties, of pistons exposed to varying weather environments. Overall, this study underlines the importance of considering air exposure in understanding and optimizing the hydration system of axial pistons and provides valuable information for improving hydraulic system efficiency and reliability. Keywords: axial pistons, hydration system, piston, hydraulic machine, rotor.

Surface activation of viscose textiles via air, argon, and oxygen dielectric barrier discharge plasma: influence of peak voltage

This paper discusses the use of atmospheric pressure dielectric barrier discharge (DBD) plasma treatment to enhance the surface qualities of viscose fabrics. The study explores the effects of different plasma gases, discharge voltages, and exposure times on the treated fabrics. The findings emphasize the importance of optimizing the plasma’s peak voltage to achieve the desired surface treatment outcomes. The document also presents data on colour strength, wettability, colour fastness, and tensile strength of the treated fabrics, as well as scanning electron microscopy (SEM) analysis of surface morphology and chemical analysis using fourier- transition infrared spectroscopy (FTIR) and energy dispersive X-ray (EDX). The results show that treatment at a peak voltage of 11.83 kV is more efficient, except for the tensile strength which is enhanced at a peak voltage of 8.92 kV. The oxygen plasma treatment significantly improves the colour strength, which exhibits an increase from 11 to 18. The intensified colour was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules, which enhance the printability. The oxygen DBD plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas. This study presents a sustainable, economical, secure, and ecologically friendly approach to explore new fabrics for specific uses.