Surface Characterization Research Articles

Surface wettability modifications and applications in wickless heat pipes

Proper methods of surface fabrication and characterization are essential for various applications. For example, wickless heat pipes, such as flat plate pulsating heat pipes (FPPHP) and a compact flat thermosyphon (CFT), have massive potential for commercialization owing to simple construction, flexibility in using different working fluids, and better thermal contact with flat heat sources. In this work, various surface treatment methods such as chemical etching, electrochemical deposition, and laser texturing on a copper sample are investigated to prepare superhydrophilic or superhydrophobic surfaces, and the thermal durability of the as-prepared surfaces is tested through heating and boiling experiments for 15 days. The wettability modification methods are implemented on the surfaces of the FPPHP and CFT, with the different wettability combinations as either bare evaporator and condenser, completely superhydrophilic (that is, all surfaces including that of evaporator, condenser, and adiabatic section) or completely superhydrophobic or hydrophilic evaporator and superhydrophobic condenser. The thermal performance of the FPPHP and CFT subjected to different wettability combinations on the surface is investigated. Results of FPPHP are reported for water as the working fluid at 60 % filling ratio with power inputs given from 40 to 200 W. Similarly, for CFT, the results are reported for water filled at 50 % filling ratio with heat flux input from 2 to 20 W/cm2. On the FPPHP, the best thermal performance and lowest resistance were obtained when the entire surface was superhydrophilic with a maximum reduction of 60 % at 200 W. The CFT gives the best thermal performance with a bare evaporator and superhydrophobic condenser with a maximum decrease in thermal resistance of 42 % at 20 W/cm2. The best-performing wettability combination for FPPHP and CFT is contrasting and has to be chosen appropriately depending on the heat transfer device.

Enhancing colloid stability of polymer microspheres in water through SiO2 coating: Effects of coating cycles and surface coverage

In this study, we investigated the wettability and agglomeration characteristics of polymer microspheres coated with low-temperature deposited SiO2 in a fluidized bed atomic layer deposition (ALD) setup. Surface characterization revealed the presence of a significant amount of deposited Si-OH groups within the first cycles. A drastic decrease in agglomerate size, water contact angle (WCA), and droplet absorption time of the powder was observed when coating was applied. Furthermore, we observed an increase in the amount of Si-OH present on the particle surface with increasing coating cycles, while no significant improvement in water affinity was found after the first coating cycles. Our findings suggest that surface coverage is the primary factor in improving the colloid stability of particles, coated at low temperatures. The low temperature operation of our system introduced a chemical vapor deposition (CVD) component to our coating process, which allowed full surface coverage to be achieved within the first two coating cycles.

Surface characterization and antibacterial efficiency of well-ordered TiO2 nanotube surfaces fabricated on titanium foams

Titanium (Ti)-based implants are not compatible enough due to their bio-inert character, insufficient antibacterial capabilities and stress-shielding problem for dental and orthopaedic implant applications. Thus, this work focused to fabricate, analyze and improve antibacterial properties titanium dioxide (TiO2) nanotube array surfaces on Ti foam by anodic oxidation (AO) process. The well-ordered nanotube arrays with approximately 75 nm were successfully fabricated at 40 V for 1 h on Ti foams. Ti and O were observed as major elements on AO-coated Ti foam surfaces. In addition, the existence of TiO2 structure was proved on AO-coated foam Ti surfaces. For potential dental and orthopedic implant application, in vitro antibacterial properties were investigated versus Staphylococcus aureus and Escherichia coli. For both bacteria, antibacterial properties of TiO2 nanotube surface were greater than bare Ti foam. The bacterial inhibition versus Staphylococcus aureus and Escherichia coli of TiO2 nanotube surfaces are improved as 53.3% and 69.4% compared to bare Ti foam.

Study on a probabilistic algorithm for the forming and 3D characterization of special-shaped surfaces under profile grinding

Study on a probabilistic algorithm for the forming and 3D characterization of special-shaped surfaces under profile grinding

Electrochemical behavior and degradation mechanism of lithium disilicate glass ceramics in acidic environment

AbstractIPS e.max Press, a lithium disilicate‐based glass ceramic, is renowned in dental restorations for its mechanical strength and aesthetic appeal. This study delves into its behavior within oral environments, employing electrochemical and surface analysis techniques. By utilizing cyclic polarization curves and impedance spectroscopy, we evaluated its degradation resistance. Surface morphology, composition, and crystal stability were explored through scanning electron microscopy (SEM)/energy‐dispersive X‐ray spectroscopy (EDX) and X‐ray powder diffraction (XRD) analysis. The glass ceramic exhibited robust resistance to localized degradation across all tested electrolytes. The degradation potential (Ecorr) varied with time and pH, indicating electrolyte influence. SEM/EDX affirmed oxide layer formation, while XRD confirmed a stable structure. While showcasing favorable resistance in saliva, citric acid, and lactic acid, IPS e.max Press demonstrated susceptibility to acetic acid. This comprehensive analysis enhances our understanding, providing valuable insights for the development of durable dental materials through a combination of electrochemical analysis and surface characterization.

Non-flammable electrolyte for large-scale Ni-rich Li-ion batteries: Reducing thermal runaway risks

We present a novel, non-flammable electrolyte for Ni-rich 18650 cylindrical lithium-ion batteries (LIBs) based on a blend of triethyl phosphate (TEP) and fluorinated ethylene carbonate (FEC). We conducted a comprehensive analysis of the electrolyte, including electrochemical tests, safety evaluations, electrode surface characterizations, and quantum calculations, to elucidate its property-function relationship. We found that combining TEP with a concentrated FEC as a co-solvent (1.2 M LiPF6 in TEP/FEC, 30/70 %v) resulted in a robust solid electrolyte interface (SEI) predominantly composed of lithium fluoride (LiF). This innovation improved the SEI's stability and suppressed electrolyte decomposition during extended cycling, leading to consistent battery performance. Our findings introduce a promising non-flammable electrolyte solution for LIBs that offers both thermal runaway prevention and seamless integration into existing battery manufacturing processes. This positions it as a potential alternative to solid-state electrolytes in advanced battery technology, with the potential to revolutionize the field.

Comparative Analysis of Tribological Behavior in Aluminum Matrix Composites Incorporating Fe75Si15Zr5B5 Metallic Glass and SiC Particles

In this study, a comparative investigation was conducted to assess the impact of Fe-based metallic glass (FMG) and silicon carbide (SiC) reinforcing particles on the tribological properties of aluminum matrix composites. The composites were synthesized using the powder metallurgy method, and subsequent dry sliding wear tests were performed by a pin-on-disc machine at ambient temperature. Thorough examinations of the microstructure, mechanical properties, and densification behavior were carried out for the developed composites, and these findings were then correlated with their wear performance. To gain insights into the wear mechanisms, comprehensive characterizations of the worn surfaces and debris were conducted utilizing field-emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDS) analysis. The outcomes of the dry sliding tests revealed that, in contrast to SiC, the addition of FMG reinforcing particles significantly decreased the friction coefficient while concurrently enhancing the wear resistance of the aluminum matrix. The microstructural investigations divulged that the pure aluminum sample experienced severe abrasive and adhesive wear mechanisms, which were effectively mitigated through the incorporation of FMG particles, due to the formation of an oxide tribolayer in the composite during the wear test. Conversely, the SiC-reinforced composites exhibited a dominant wear mechanism characterized by severe delamination, which consequently contributed to their elevated wear rate. These findings shed light on the distinct effects of FMG and SiC particles on the tribological properties of aluminum matrix composites, providing valuable insights for potential applications in engineering and industrial sectors, particularly in scenarios involving metal-to-metal contact.

Electrochemical Hydrogen Charging on Corrosion Behavior of Ti-6Al-4V Alloy in Artificial Seawater

This study employs advanced electrochemical and surface characterization techniques to investigate the impact of electrochemical hydrogen charging on the corrosion behavior and surface film of the Ti-6Al-4V alloy. The findings revealed the formation of γ-TiH and δ-TiH2 hydrides in the alloy after hydrogen charging. Prolonging hydrogen charging resulted in more significant degradation of the alloy microstructure, leading to deteriorated protectiveness of the surface film. This trend was further confirmed by the electrochemical measurements, which showed that the corrosion resistance of the alloy progressively worsened as the hydrogen charging time was increased. Consequently, this work provides valuable insights into the mechanisms underlying the corrosion of Ti-6Al-4V alloy under hydrogen charging conditions.

Surface treatments of the zirconia-reinforced lithium disilicate ceramic in the adhesion to the resin cement.

This study verified the effect of surface treatments of the zirconia-reinforced lithium disilicate ceramic bonded to resin cement. Ceramic blocks were divided according to treatments (n=10): FA+SRX (Fluoric acid + silane RX), FA+MDP (Fluoric acid + MDP), FA+SCF+MDP (Fluoric acid + silane CF + MDP), FA+MEP (Fluoric acid + MEP), and MEP (Self-etch primer). Resin cement cylinders were made in the ceramic blocks, photoactivated with 1,200 mW/cm² for 40s, stored in water at 37°C for 24h, and evaluated by the microshear strength test, optical failure descriptive analysis (%), surface characterization (SEM) and contact angle (Goniometer). Other samples were submitted to 10,000 thermocycles between 5°C and 55°C. Bond strength data were submitted to two-way ANOVA and Tukey's test. Contact angle to one-way ANOVA and Games-Howell's test (5%). At 24h, MEP showed higher bond strength, and FA+SRX the lower. FA+MDP and FA+SCF+MDP showed similar values and FA+MEP was intermediate. After thermocycling, FA+SCF+MDP, FA+MEP, and MEP showed higher values, and FA+SRX the lower while FA+MDP was intermediate. When the periods were compared, FA+MDP, FA+SCF+MDP, FA+MEP, and MEP showed higher values for 24h while FA+SRX was similar. SEM showed retentive surface and crystal exposure when treated with FA+SCF+MDP. The less retentive surface was obtained with MEP, and the other treatments promoted intermediate irregularities. In conclusion, surface treatment and thermocycling promoted different values of adhesive strength and contact angle in a zirconia-reinforced lithium silicate ceramic. Failures were predominantly adhesive, and the ceramic surface was characterized by different levels of roughness and selective exposure of crystals.

Exploring fullerene derivatives for optoelectronic applications: synthesis and characterization study.

In this study, we conducted a comprehensive investigation of newly synthesized fullerene derivatives developed for potential application in perovskite solar cells (PSCs). We explored three novel dihydrofuran-fused C60 fullerene derivatives (13, 14, and 15) that were specifically designed to enhance solubility and interaction with the substrate, fluorine-doped tin oxide (FTO). A comparative analysis was performed, with reference to the widely used phenyl-C61-butyric acid methyl ester (PCBM) and compound 12, from which 13, 14, and 15 are derived, to assess the impact of sugar units on materials properties. The synthesized compounds demonstrated significant solubility in common organic solvents, a critical factor in their potential application in wet-processed PSCs. Our investigation included electrochemical property analysis, thin film deposition, surface characterization, and electrochemical impedance spectroscopy (EIS). EIS measurements unveiled key insights into charge transfer properties at the electrode/electrolyte interface, making the compounds attractive candidates for electron transport layers (ETLs) in PSCs.

Tailoring magnetic Sn-MOFs for efficient amoxicillin antibiotic removal through process optimization.

This study investigated the efficacy of magnetic Sn metal-organic frameworks (MSn-MOFs) in removing the insecticide amoxicillin (AMX) from aqueous solutions. Our thorough experimental investigation showed that MSn-MOFs were an incredibly effective adsorbent for removing AMX. Several methods were used to characterize the material. BET investigation of the data displayed a significant surface area of 880 m2 g-1 and a strong magnetic force of 89.26 emu g-1. To identify the point of zero charge, surface characterization was carried out and the value was 7.5. This shows that the adsorbent carries a positive and negative charge below and above this position, respectively. Moreover, the impact of pH on adsorption equilibrium was explored. The results of kinetic models to explore the adsorption of AMX on MSn-MOFs supported the pseudo-second-order, and the adsorption complied well with the Langmuir isotherm. The results revealed that the overall adsorption mechanism may entail chemisorption via an endothermic spontaneous process with MSn-MOFs. The precise modes by which MSn-MOFs and AMX interacted may involve pore filling, H-bonding, π-π interaction, or electrostatic interaction. Determining the nature of this interaction is essential in understanding the adsorption behavior of the MOFs and optimize the adsorbent design for real-world applications. The use of the MSn-MOF adsorbent provides a straightforward yet efficient method for the filtration of water and treatment of industrial effluents. The results showed 2.75 mmol g-1 as the maximum capacity for adsorption at pH = 6. Additional tests were conducted to assess the adsorbent regeneration, and even after more than six cycles, the results demonstrated a high level of efficiency. The adsorption results were enhanced by the application of the Box-Behnken design.

Enhancing corrosion resistance of mild steel in hydrochloric acid with Chiquita banana sap extract.

The corrosion of metals is still a huge challenge for various industries, and the pursuit of effective treatments ensures environmental sustainability. In this study, we utilized Chiquita banana sap-water extract (BSWE) to prevent mild steel from electrochemical corrosion in a 0.1 M HCl at room temperature. Corrosion resistance was assessed using various electrochemical methodologies, combining with surface characterization techniques. The results showed a high level of effectiveness when the corrosion current density decreased from 3292.67 μA cm-2 (for the sample immerged in the blank solution) to 187.33 μA cm-2 after 24 hours of immersion in the solution containing BSWE at a 2000 ppm concentration, equivalent to corrosion efficiency of 94.32%. Surface characterization revealed diminished corrosion on the inhibited steel surface due to the formation of a protective layer. X-ray photoelectron spectroscopy results demonstrated the presence of BSWE ingredients combining with iron oxides and hydroxides to form a smooth protective layer. Furthermore, theoretical calculations also indicated that the addition of BSWE can reduce steel surface damage when exposing to corrosive environment. The inhibitor based on banana sap extract can be referred to as a sustainable protective coating since it is biodegradable, abundantly available in banana plants and free of other harmful substances.

Characterization of bacterial surface leached silica using 3D profilometry: Insights and Applications

Characterization of bacterial surface leached silica using 3D profilometry: Insights and Applications

Production and Characterization of Bioactive and Antimicrobial Titanium Oxide Surfaces with Silver Nanoparticles and a Poly(lactic Acid) Microfiber Coating

Silver nanoparticles (AgNp) were deposited on highly porous TiO2 surfaces by the dripping of a colloidal AgNp solution to provide antimicrobial activity. Micro-porous TiO2 surfaces were obtained on commercially pure titanium by micro-arc oxidation in an electrolyte containing Ca and P precursors. In addition, as silver can be toxic to cells, these surfaces were uniformly covered with the biocompatible and bioresorbable poly(lactic acid) (PLA) polymer by electrospinning, aiming at promoting a controlled release of silver ions to the medium. The resulting AgNp-containing surfaces were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), and in vitro assays were performed to evaluate their antimicrobial activity and bioactivity. Tests revealed that the surfaces showed antimicrobial activity against Staphylococcus aureus, with better results for the surfaces without PLA. However, all the surfaces presented good biocompatibility in assays with mouse MC3T3-E1 pre-osteoblasts, and greater cell differentiation for the polymer-coated surfaces. Finally, the PLA ultrafine fibers electrospun on the TiO2/AgNp surfaces allowed a controlled release of silver ions in the phosphate-buffered saline (PBS) medium.

Tribological behaviors of an attapulgite-graphene nanocomposite as an additive for mineral lubricating oil.

In this work, an attapulgite-graphene nanocomposite was prepared. The tribological properties of the prepared attapulgite-graphene nanocomposite as an additive for 200SN mineral lubricating oil were investigated using an SRV-IV tribometer through ball-on-disk contact mode for the first time. The characterization of the prepared nanocomposite indicated that attapulgite nanofibers are enveloped by the graphene nanosheets and present fine combination. The tribological test results show that the friction-reducing and antiwear properties of 200SN were obviously improved by adding the attapulgite-graphene nanocomposite. Through the characterization and analysis of the worn surface and cross-section, it was found that a tribofilm composed of Fe, Fe3O4, FeO, Fe2O3, FeOOH, graphite, graphene, SiO2 and organic compounds was formed on the worn surface. Furthermore, the bonding between the tribofilm and steel matrix is tight. The tribofilm and lubricating oil achieve a solid-liquid coupling lubrication effect, which is responsible for the improvement of the friction-reducing and antiwear properties.

Synthesis, crystal structure, spectroscopic characterization, in vitro and in silico studies of water-soluble (Z)-N'-hydroxy-2-morpholinonicotinimidamide

A water-soluble compound (Z)-N'-hydroxy-2-morpholinonicotinimidamide was synthesized, and it has a multi-functional group, such as morpholine, pyridine, and oxime. The synthesized compound was characterized by various spectroscopic techniques such as NMR, FT-IR, UV-visible, Elemental analysis, and single-crystal XRD. The molecule was investigated using computational methods, such as DFT and MEP, to determine the electronic characterization of the molecule's surface. With the aid of these studies, docking experiments were also performed with diabetic and inflammatory-responsible enzymes. The results are matched with in vitro anti-diabetic and anti-inflammatory studies where protein inhibition methods were followed. The acquired results strongly imply that the compound may be investigated for better activity in vivo studies, given that it can support the biological system regarding solubility.

Oyster mushroom drying in tray dryer: Parameter optimization using response surface methodology, drying kinetics, and characterization

In this study, the drying of oyster mushrooms (P. ostreatus) in a tray dryer was optimized. The parameters used to optimize the drying process were drying temperature, airspeed, mass loading, and moisture content. Its drying kinetics were investigated at the optimum drying parameters. A quadratic equation was obtained to predict the moisture content of mushrooms at the given drying temperature, airspeed, and mass loading, and it was validated against experimental results. A minimum moisture content (9.99 wt%) was obtained at the optimum conditions of 60 °C, 3 m/s airspeed, and mass loading of 200 g using a tray dryer. Proximate analysis, shelf-life analysis, inorganic elemental analysis, and functional group analysis were done as a characterization method for mushrooms after drying at the optimum drying conditions. About 27.8 wt% protein and 50.2 wt% carbohydrates were found in proximate results. Besides, potassium and sodium were the dominant elements as estimated by spectrophotometry analysis. The induction period (IP) of dried mushrooms at room temperature is 3520:47 (hour: minute) from the oxidation stability analysis, and the water activity of dried mushrooms was found to be 0.36. The drying kinetics of oyster mushrooms were studied at various temperatures (50–75 °C), optimum airspeed (3 m/s), and mass loading (200 g). The best-fit model describing the mushrooms drying kinetics was found to be Midilli et al., with the lowest RMSE (0.008749), X2 (0.0014), and the highest R2(0.9993) values. The kinetic triplet activation energy, effective diffusivity, and diffusivity constant (Ea, Deff, D0) for oyster mushrooms drying were determined and found to lay in the general range for foodstuffs. The value of Deff results lies within the range of 10−8 to 10−12 m2/s, with Ea of 15.32 kJ/mol and D0 value 2.263 × 10−6 m2/s.

Synthesis, crystal structure, Hirshfeld surface analysis and characterization of two new mononuclear Ni(II) complexes.

Two new mononuclear Nickel(II) Schiff base complexes [NiL2] (1) and [NiL2(DMSO)2] (2) where HL is 2,4-dibromo-6-[(E)-{[2-(thiophen-2-yl)ethyl]imino}methyl]phenol, a bidentate Schiff base prepared from the condensation reaction of 2-thiopheneethylamine and 3,5dibromosalicylaldehyde, have been made. Complexes 1-2 are characterized by FTIR, UV-Vis. absorption spectra, TGA analysis (for 2), and single-crystal X-ray diffraction studies. Complexes 1-2 crystallize in a similar space group P21/c as a monoclinic system. X-ray crystallography data indicate that complex 1 has a distorted square planar geometry whereas 2 has distorted octahedral geometry. Using the crystallographic data, the Hirshfeld surface (HS) analysis was also carried out to examine the nature and quantitative contribution of all potential non-covalent intermolecular interactions inside the crystal lattice. Supramolecular chains in 1 through Br∙∙∙Br and π∙∙∙π interactions and in 2 via C‒Br∙∙∙π intermolecular interactions have been observed. The interaction energies between molecules within the crystals were computed to get idea about molecular packing stabilization.

TNF‐a/IL‐1B cytokine licensing enhances immunomodulatory potential of allogeneic mesenchymal stromal cells

Aims/Purpose: Mesenchymal stromal cells (MSCs) have shown great potential for therapeutic treatment of inflammatory diseases; however, their immunomodulatory potential can be further enhanced by cytokine licensing. The aim of this work was to assess changes in MSC surface characterization profile and immunomodulatory function following licensing with TNF‐α/IL‐1β pro‐inflammatory cytokines.Methods: MSCs were isolated from the bone marrow of FVB mice (H2kq) and licensed with a combination of 50 ng/mL TNF‐α and 50 ng/mL IL‐1β or cultured in growth medium alone. MSCs were harvested following 72‐h cytokine stimulation and added to immune cell potency assays. Characterization of MSC surface marker expression was assessed by flow cytometry. The immunology potential of FVB MSCs as an allogeneic cell therapy was assessed in vitro through co‐culture with Balb/c (H2kd) αCD3/CD28 activated T lymphocytes or Balb/c IFN‐γ/LPS‐stimulated macrophages.Results: TNF‐α/IL‐1β licensing was found to induce surface marker phenotype alterations compared with unlicenced MSCs, with increased expression of CD73, CD44, Sca‐1, CD29 and PD‐L1 observed. TNF‐α/IL‐1β licensed MSCs also secreted significantly higher quantities of nitric oxide compared with their untreated counterparts at two separate timepoints, 24‐h and 42‐h post‐stimulation. TNF‐α/IL‐1β MSCs significantly suppressed both CD4+ and CD8+ T cell proliferation at three different rations (1:5, 1:10, 1:50 MSCs: T cells) and significantly increased expansion of CD4+CD25++FoxP3+ regulatory T cells following co‐culture. TNF‐α/IL‐1β MSCs were found to significantly decrease levels of IFN‐γ from proliferating T cells. TNF‐α/IL‐1β MSCs were positive for CD80 expression had significantly reduced MHC I expression and could increase expansion of CD206 on M1‐like macrophages. Both T cell and macrophage co‐cultures with TNF‐α/IL‐1β MSCs showed a significant increase in IL‐6.Conclusions: Our results show the potential to enhance the therapeutic effects of MSC through cytokine licensing. Currently, TNF‐α/IL‐1β MSCs are being tested in ocular surface injury models for therapeutic efficacy.Keywords: Mesenchymal Stromal Cells, Cytokine Licensing, Immunomodulation, TNF‐α/IL‐1β.

Road Surface Characterization Using a 77–81 GHz Polarimetric Radar

Road Surface Characterization Using a 77–81 GHz Polarimetric Radar