Surface Free Energy Research Articles

In situ shale wettability regulation using hydrophobic ionic liquid functionalized nano-silica to enhance wellbore stability in deep well drilling

Shale wellbore instability due to hydration significantly hinders the efficient extraction of clean shale gas resources, making the development of effective shale stabilizers for safe drilling in shale reservoirs an urgent priority. In this study, we proposed an innovative application of hydrophobic ionic liquids functionalized nano-SiO2 (ILs@SiO2) specifically designed to maximize hold wellbore strength and effectively inhibit shale hydration. The chemical composition and microstructure of ILs@SiO2 were characterized, and their effects on wellbore stability were thoroughly investigated along with the underlying mechanisms. The shale stabilizer demonstrated significant clay swelling inhibition (9.5 %), as well as effective hydration and dispersion inhibition of shale cuttings at 150 °C (88.0 %), and a reduced spontaneous imbibition of shale (0.997 g). Particularly, ILs@SiO2 maximized maintained wellbore strength (203.4 MPa) and minimized water invasion (5.5 mL). Mechanism analysis revealed that ILs@SiO2 improved wellbore stability through electrostatic adsorption weakening osmotic hydration, physical plugging establishing a dense preventing water barrier, altering wettability decreasing rocks surface free energy, inhibiting surface hydration, and reversing the direction of capillary forces. This study offers new strategies and insights for constructing methods to plug shale nanopores and inhibit surface and osmotic hydration.

Early Biological Response to Poly(ε-Caprolactone)/Alumina-Toughened Zirconia Composites Obtained by 3D Printing for Peri-Implant Application.

The improvement of the mucosal sealing around the implant represents a challenge, one that prompted research into novel materials. To this purpose, a printable poly(ε-caprolactone) (PCL)-based composite loaded with alumina-toughened zirconia (ATZ) at increasing rates of 10, 20, and 40 wt.% was prepared, using a solvent casting method with chloroform. Disks were produced by 3D printing; surface roughness, free energy and optical contact angle were measured. Oral fibroblasts (PF) and epithelial cell (SG) tests were utilized to determine the biocompatibility of the materials through cell viability assay and adhesion and spreading evaluations. The highest level of ATZ resulted in an increase in the average roughness (Sa), while the maximum height (Sz) was higher for all composites than that of the unmixed PCL, regardless of their ATZ content. Surface free energy was significantly lower on PCL/ATZ 80/20 and PCL/ATZ 60/40, compared to PCL and PCL/ATZ 90/10. The contact angle was inversely related to the quantity of ATZ in the material. PF grew without variations among the different specimens at 1 and 3 days. After 7 days, PF grew significantly less on PCL/ATZ 60/40 and PCL/ATZ 80/20 compared to unmixed PCL and PCL 90/10. Conversely, ATZ affected and improved the growth of SG. By increasing the filler amount, PF cell adhesion and spreading augmented, while PCL/ATZ 80/20 was the best for SG adhesion. Overall, PCL/ATZ 80/20 emerged as the best composite for both cell types; hence, it is a promising candidate for the manufacture of custom made transmucosal dental implant components.

Ion adsorption-enrichment effect and its driving mechanism for nano-dots lithography with SPM probe on water-soluble crystal surfaces

HypothesisWater-soluble KDP (KH2PO4) crystals possess excellent optical properties and are employed as frequency converters in clean fusion energy. To improve their performances, there is an immediate necessity to lithograph surface nano-patterns on them. Although the Scanning Probe Microscope (SPM) provides a promising way to achieve this purpose through the water menisci, the driving mechanisms of the lithographic behaviors have not yet been revealed. Simulations and ExperimentsMulti-scale investigations are constructed to explore the underlying driving mechanisms. The SPM probe-induced ion diffusion-transport behaviors are investigated by molecular dynamics. The ion adsorption-enrichment mechanisms are revealed by 18 adsorption models via the ab initio. The SPM probe-induced self-assembly experiments are performed to prove the local heavy concentration. A comprehensive model is developed to describe the lithography mechanisms of the probe-induced self-assembly nano-dots on water-soluble substrates. FindingsIt is interestingly found that the KDP growth units (H2PO4−) exhibit obvious adsorption-enrichment effect at 3.16 Å from the probe surface, causing local heavy concentration. The H2PO4− would spontaneously adsorb onto the probe surface, which is dominated by the Si-O bonding reactions. The nano-dots with the height of 27 ∼ 48 nm and diameter of 2.0 ∼ 2.7 μm are lithographed on the KDP substrate. The proposed model further confirms that the lithography processes are driven by the solution supersaturation, solute diffusion, and surface free energy.

Charge regulation of nanoparticles in the presence of multivalent electrolytes.

We explore the charge regulation (CR) of spherical nanoparticles immersed in an asymmetric electrolyte of a specified pH. Using a recently developed reactive canonical Monte Carlo (MC) simulation method, titration isotherms are obtained for suspensions containing monovalent, divalent, and trivalent coions. A theory based on the modified Poisson-Boltzmann approximation, which incorporates the electrostatic ion solvation free energy and discrete surface charge effects, is used to compare with the simulation results. A remarkably good agreement is found without any fitting parameters, both for the ion distributions and titration curves, suggesting that ionic correlations between coions and hydronium ions at the nanoparticle surface play only a minor role in determining the association equilibrium between hydroniums and the functional sites on the nanoparticle surface. On the other hand, if suspension contains multivalent counterions, we observe a large deviation between theory and simulations, showing that the electrostatic correlations between counterions and hydronium ions at the nanoparticle surface are very significant and must be properly taken into account to correctly describe CR for such solutions.

Interlayer Adhesion of Coating System in Analogue and Digital Printing Technologies Formed on Lightweight Honeycomb Furniture Panels

This article concerns research into the influence of the energy dose distributed by UV lamps on selected parameters of varnish coatings formed during the varnishing process of lightweight cellular panels. The lightweight cellular board used in the study was made according to an innovative solution. The surface finishing of the boards was carried out using the roller method in combination with digital and analogue printing under industrial conditions. Contact angle measurements of the obtained varnish coatings were carried out, from which the surface free energy was calculated. In addition, interlayer adhesion was assessed by pull-off tests. Irrespective of the radiation dose, higher contact angle values (54.3–89.9°) were recorded for the last two applied layers (base coat 2 and base coat 3) than for the other coatings (39.6–64.1°). For all systems tested, the γsp component showed lower values (2.25–28.99 mJ/m2) than γsd (28.66–32.80 mJ/m2). The adhesion test results ranged from 0.5 to 0.9 MPa, although with varying types of delamination. Based on the test results, the most favourable variants from the furniture manufacturer’s point of view were selected that provided the desired level of adhesion, in which cohesive damage located within the substrate (A) predominated.

Relationship between the surface free energy of underlayers and the dissolution kinetics of poly(4-hydroxystyrene) partially protected by t-butoxycarbonyl groups in tetramethylammonium hydroxide aqueous developer

In the lithography used for the high-volume production of semiconductor devices, the photoresist film becomes thin with the reduction in pattern size to prevent the pattern collapse due to the surface tension of rinsing liquids. The interfacial effect becomes strong with the reduction in photoresist film thickness. In the development process, it is of importance to clarify the relationship between the photoresist and the underlayer for fine patterning. In this study, the dissolution kinetics of poly(4-hydroxystyrene) (PHS) partially protected by t-butoxycarbonyl (t-Boc) groups in tetramethylammonium hydroxide (TMAH) aqueous solution was found to be related to the surface free energy of the underlayer. The attenuation rate of developer viscosity first decreased and then increased with the polar-to-dispersion component ratio. An inflection point with the lowest rate existed. The TMAH concentration affected not only the attenuation rate but also the ratio of polar to dispersion components at the minimum attenuation rate.

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.

Analysis of the competitive influence of gas adsorption and interface modification on the surface free energy of coal matrix

Coal is a complex porous medium characterized by numerous pores and fractures within its internal structure, which provide a natural space for the storage of coalbed methane. The high surface free energy of coal significantly inhibits the efficient extraction of coalbed methane, resulting in the escape of considerable amounts of greenhouse gas during the later stages of coal mining. This exacerbates the challenges and costs associated with environmental governance. According to the principle of minimum capacity, the surface of the coal matrix reduces its surface free energy through gas adsorption. To investigate the competitive influence of gas adsorption and interface modification on the surface free energy of the coal matrix, isothermal adsorption and contact angle determination experiments were conducted. The results indicate that as equilibrium pressure increases, the amount of gas adsorption on the surface of the coal matrix also increases, while the adsorption potential exhibits a contrasting trend. Under the influence of gas adsorption, there is a significant increase in Gibbs variation, indicating a substantial decrease in the surface free energy of the coal matrix. Under the influence of interface modification, an increase in surfactant concentration resulted in a trend of energy reduction characterized by an initial increase followed by a subsequent decrease. Moreover, interface modification effectively eliminated the water-blocking effect, leading to a significant enhancement in gas desorption. Consequently, interface modification offers important theoretical support for improving production in coalbed methane and mitigating the greenhouse effect.

Modifying of surface properties and structural characteristics of low energy argon beam irradiated methylcellulose/TiO2 nanocomposite films

Flexible polymeric nanocomposites MC/TiO2 films, which consisting of titanium dioxide (TiO2) and methyl cellulose (MC) were fabricated in this research for applied in coating devices. The successful manufacturing of MC/TiO2 sheets were verified by FTIR, SEM and XRD methods, which demonstrated a uniform distribution of TiO2 in MC. Additionally, the chemical bonds of MC and TiO2 contribute for the broadening and decreasing of MC in the peaks intensity of XRD and FTIR with increasing TiO2, indicating the successful incorporation of TiO2 in MC. The impacts of argon beam bombardment on MC/TiO2 composites using cold cathode source with fluencies (2.5×1015, 5×1015 and 7.5×1015 ions/cm2 ). The contact angle, work of adhesion and surface free energy of MC/TiO2 were determined as a function of ion irradiation. The water contact angle is decreased from 70.32o to 43.34o by increasing ion fluence from 2.5×1015 ions/cm2 to 7.5×1015 ions/cm2 , while the surface free energy is enhanced from 38.83 mJ/m2 to 64.17 mJ/m2 . The collected data confirmed that the surface wettability of the irradiated MC/TiO2 films were improved to be can usage in coating and printing applications

Insights in the wettability of hard chromium coated steel for cold rolling applications

The use of toxic Cr (VI) in the chrome plating process poses significant health risks, highlighting the urgent need to find sustainable alternatives for many applications such as cold rolling. Understanding key properties of functional chrome coating in lubricated industrial processes, especially its wetting properties that can support lubrication, low friction, and durability, is essential for the development of safer coating processes. However, the wetting properties of hard chromium coating are not fully understood. This study investigates the wetting characteristics of chromium coatings in comparison to uncoated steel. The study explores the dynamic wetting behavior by conducting contact angle measurements with water and lubricant oil, determining surface free energy using the sessile drop method, and characterizing the surface through X-ray photoelectron spectroscopy analysis. The findings reveal that a standard hard chrome coating exhibits superior wettability by both water and oil and higher surface energy compared to uncoated steel. The research, supported by theoretical modelling, highlights that factors are not limited to chromium alone, but rather involve a multilayer system that includes chromium oxide and organic contaminations, which have a substantial impact on surface properties and wettability. Increased levels of organic contamination on the chrome-coated surface, are shown to result in weaker intermolecular interactions with the contacting fluid, leading to reduced surface affinity to water and consequently result in higher contact angles. Our findings provide critical insights into the intricate nature of chromium coatings and lay foundations for developing sustainable alternatives.

Fabrication of omniphobic PVDF membrane with SiO2–FeOOH hierarchical structures for robust membrane distillation

Omniphobic membrane has been demonstrated as an effective strategy to mitigate membrane wetting and fouling risks in membrane distillation (MD) processes. In this work, novel omniphobic membranes with hierarchical re-entrant surface structure were fabricated. Firstly, the FeOOH nanorods were deposited on the polydopamine (PDA) pre-treated poly (vinylidene fluoride) PVDF membrane. After that, the SiO2 nanoparticles (NPs) were coated on the FeOOH nanorods via electrostatic attraction to form hierarchical structures. Finally, the fluorosilane was utilized to reduce the membrane surface free energy, contributing to PVDF based omniphobic membranes. The effects of reaction time, FeCl3·6H2O and SiO2 NPs concentrations on membrane properties, including membrane surface morphology, average pore size, contact angles (CAs), surface roughness and permeate flux, were investigated in detail. The resulting omniphobic membranes showed high CAs towards various tested liquids, such as 0.4 mM sodium dodecyl sulfate (SDS) solution (143.9 ± 0.8°), hexadecane (113.5 ± 3.2°) and mineral oil (132.5 ± 2.8°). This membrane exhibited outstanding performance in a continuous 50-h vacuum membrane distillation (VMD) process with a 10 wt% NaCl feed solution. Besides, the anti-oil-fouling properties were further assessed with a feed solution containing 200-ppm hexadecane and 3.5-wt% NaCl, the omniphobic membrane exhibited steady permeate flux of above 24.18 kg m−2 h−1 and a 99.99 % rejection rate during 50-h testing. Finally, the omniphobic membrane showed high anti-wetting properties by SDS/salt solution. This work introduces a new strategy for fabricating omniphobic membranes that shows significant potential for treating complex industrial wastewaters.

Confinement-Driven Dimethyl Ether Carbonylation in Mordenite Zeolite as an Ultramicroscopic Reactor.

ConspectusThe conversion of C1 molecules to methyl acetate through the carbonylation of dimethyl ether in mordenite zeolite is an appealing reaction and a crucial step in the industrial coal-to-ethanol process. Mordenite zeolite has large 12-membered-ring (12MR) channels (7.0 × 6.5 Å2) and small 8MR channels (5.7 × 2.6 Å2) connected by a side pocket (4.8 × 3.4 Å2), and this unique pore architecture supplies its high catalytic activity to the key step of carbonylation. However, the reaction mechanism of carbonylation in mordenite zeolite is not thoroughly established in that it is able to explain all experimental phenomena and improve its industrial applications, and the classical potential energy surface exerted by static density function theory calculations cannot reflect the reaction kinetics under realistic conditions because the diffusion kinetics of bulk DME (kinetic dimeter: 4.5 Å) and methyl acetate (MA, kinetic dimeter: 5.5 Å) were not well considered and their restricted diffusion in the narrow side pocket and 8MR channels may greatly alter the integrated kinetics of DME carbonylation in mordenite zeolite. Moreover, the precise illustration of the dynamic behaviors of the ketene intermediate and its derivatives (surface acetate and acylium ion) confined within various voids in mordenite has not been effectively portrayed.Advanced ab initio molecular dynamics (AIMD) simulations with or without the acceleration of enhanced sampling methods provide tremendous opportunities for operando modeling of both reaction and diffusion processes and further identify the geometrical structure and chemical properties of the reactants, intermediates, and products in the different confined voids of mordenite under realistic reaction conditions, which enables high consistency between computations and experiments.In this Account, the carbonylation process in mordenite is comprehensively described by the results of decades of continuous research and newly acquired knowledge from both multiscale simulations and in-(ex-)situ spectroscopic experiments. Three primary steps (DME demethylation to surface methoxy species (SMS), carbon-carbon bond coupling between SMS and CO to acetyl species, and methyl acetate formation by acetyl species and methanol/DME) have been respectively studied with a careful consideration of different molecular factors (reactant distribution, concentration, and attack mode). By utilizing the free-energy surface of diffusion and reaction obtained from AIMD simulations, a comprehensive reaction/diffusion kinetic model was formulated for the first time, illustrating the entire zeolite catalytic process. In this context, a comprehensive and informative analysis of the reaction kinetics of carbonylation in mordenite, including the function of the 12MR channels, 8MR channels, and side pockets in the adsorption, diffusion, and reaction of DME carbonylation, was performed. The different channels of mordenite play different roles in all ordered reaction steps, illustrating a highly organized ultramicroscopic reactor that is encompassed.

Influence of Surface Pretreatment on the Bond Strength of a Resin Luting Cement to Saliva-contaminated Enamel and Dentin.

This study aimed to evaluate the influence of surface pretreatment on the shear bond strength (SBS) of a resin luting cement to enamel and dentin with saliva contamination. The surface free energies (SFE) of the adherent surfaces were also determined. Bovine enamel and dentin were used in this study. For the saliva-contamination, human saliva was applied to the adherent surface for 60 seconds and then air-dried, and the specimens without saliva contamination served as controls. One group of contaminated surfaces was untreated (SC), and the others were pretreated with Katana Cleaner (KC), Multi Etchant (ME), or Ultra-Etch (UE). Fifteen specimens were prepared to measure the SBS for each test group.The mixed resin luting cement paste was applied to the alumina-blasted surface of a stainless-steel rod and placed on the prepared tooth surface. The luting cement was light irradiated for 40 seconds. The bonded specimens were stored for 24 hours at 37°C and half of the bonded specimens underwent 10,000 thermal cycles. The SBS and SFE of the specimens after different pre-treatments were measured. The two-way ANOVA revealed that the factors of pretreatment agent and storage condition had a significant effect on the SBS to enamel and dentin. The SFE values of the SC group were significantly lower than those of the other groups in both enamel and dentin. The SFE of pretreated surface was material dependent. A pretreatment agent containing functional monomers was shown to be effective in removing saliva contaminants and in creating an effective bonding surface for the resin luting cement.

Transition metal atom on the two-dimensional Dirac structure RhB4/OsB4: A novel multifunctional electrocatalyst

The design of low-cost multifunctional electrocatalysts with high carrier mobility, high surface free energy and base surface activity facilitates hydrogen evolution reactions (HER) and oxygen reduction reactions (ORR), which are essential for the development of clean energy. Recent studies have shown significant progress in developing HER/ORR bifunctional catalysts, such as transition metal alloys, oxides, sulfides, and carbon-based composites. These materials are highly efficient in catalysis and help reduce costs. In this work, density functional theory is used to predict the performance of single atom catalysis (SACs) embedded with transition metal (TM) using two-dimensional (2D) Dirac node-ring semi-metal RhB4/OsB4 monolayer as substrate. Systematic calculations show that the TM@RhB4/OsB4 structure with thermodynamic and kinetic stability presents multiple active sites on the basal surface. Notably, Fe@RhB4 is an excellent hydrogen evolution reaction HER catalyst because Dirac cones occur near the Fermi level of this structure, providing high carrier densities and accelerating charge transfer between the catalyst and reaction intermediates. When the substrate RhB4/OsB4 is modified by Sc and Cu atoms, the band gap of the structure becomes small, which increases the conductivity of the original structure. The ΔGH* values of Sc@RhB4 and Cu@OsB4 were 0.118, and 9.38 meV, respectively, outperforming the ideal catalyst Pt. In addition, it is found that Fe@RhB4, and Mn@OsB4 exhibit outstanding catalytic properties for the oxygen reduction reaction (ORR), with overpotentials of 0.41V, and 0.40V, respectively, surpassing the performance of the reference catalyst Pt. It is exciting that the Fe@RhB4 exhibits ideal HER/ORR bifunctional electrocatalytic properties. This study will provide a theoretical basis for the development of multifunctional electrocatalysts in the field of Dirac nodal ring semi-metal materials by single atom doping technology.

Effect of Carboxymethyl Cellulose and Polyvinyl Alcohol on the Dispersibility and Chemical Functional Group of Nonwoven Fabrics Composed of Recycled Carbon Fibers.

In this study, recycled carbon fibers (rCFs) recovered from waste carbon composites were used to manufacture wet-laid nonwoven fabrics. The aim was to improve dispersibility by investigating the changes in the dispersibility of carbon fibers (CFs) based on the content of the dispersant carboxymethyl cellulose (CMC) and the binder polyvinyl alcohol (PVA), and the length and basis weight of the CFs. In addition, the chemical property changes and oxygen functional group mechanisms based on the content of the CMC dispersant and PVA binder were investigated. The nonwoven fabrics made with desized CFs exhibited significantly improved dispersibility. For nonwoven fabrics produced with a fixed binder PVA content of 10%, optimal dispersibility was achieved at a dispersant CMC concentration of 0.4%. When the dispersant CMC concentration was fixed at 0.4% and the binder PVA content at 10%, the best dispersibility was observed at a CF length of 3 mm, while the maximum tensile strength was achieved at a fiber length of 6 mm. Dispersibility remained almost consistent across different basis weights. As the dispersant CMC concentration increased from 0.2% to 0.6%, the oxygen functional groups, such as carbonyl group (C=O), lactone group (O=C-O), and natrium hydroxide (NaOH), also increased. However, hydroxyl group (C-O) decreased. Moreover, the contact angle decreased, while the surface free energy increased. On the other hand, when the dispersant CMC concentration was fixed at 0.4%, the optimal binder PVA content was found to be 3%. As the binder PVA content increased from 0% to 10%, the formation of hydrogen bonds between the CMC dispersant and the PVA binder led to an increase in C=O and O=C-O bonds, while C-O and NaOH decreased. As the amount of oxygen increased, the contact angle decreased and the surface free energy increased.

Bacterial Adhesion to Natural and Synthetic Fibre-Forming Polymers: Influence of Material Properties.

Polymer-based textiles have a major impact on human well-being, as they provide the desired functional protection and aesthetic comfort when worn. However, natural and synthetic polymer-based textiles can also pose serious health risks, as they are surfaces that allow the adhesion of various bacteria, including pathogenic bacteria. To minimise these problems, antibacterial chemical treatments are generally applicable in the case of polymer-based textiles. However, to avoid the use of potentially toxic chemicals, sustainable approaches require the customised design of non-adhesive polymer-based textiles, considering their chemical, physicochemical, constructional, and textural properties. Before designing, several articles are required to gain sufficient knowledge of the described object. Despite the urgent need to combat bacteria (on polymer-based textiles), which pose a serious global health risk, only a few review articles have been published that address bacterial adhesion in the context of superhydrophobic and antibacterial textile materials, while only one review article holistically addresses the textile factors and their influence on this phenomenon. The aim of this review article is to expand the insufficient knowledge about bacterial adhesion to polymer-based textiles on the basis of theoretical findings and real examples through a high degree of structuring, simplification, holistic consideration, and visualization. Therefore, this review provides an insight into the mechanisms involved in bacterial adhesion and a comprehensive overview of the influence of different textile factors, such as chemical composition, hydrophilicity/hydrophobicity, surface charge, surface free energy, roughness, and porosity, on bacterial adhesion. To emphasise the importance of the synergistic effect of the combined textile factors, examples of the influence of hydrophilicity/hydrophobicity in combination with surface charge, surface roughness, and porosity are discussed. From the review, it can be concluded that the combination of hydrophilicity/hydrophobicity and the surface charge of textile fibres and bacteria is crucial for bacterial adhesion, with roughness and porosity being the most important factors among the constructive and textural properties of polymer-based textiles.

Effects of surface anisotropy on the surface morphological response of plasma-facing tungsten

Surface free energy has been hypothesized as the cause behind the experimental evidence (Parish et al., 2014) of a strong correlation between crystallographic orientation and surface morphology changes in helium ion-irradiated tungsten at the early stages of ‘fuzz’ growth in fusion plasma-facing tungsten. Here, this hypothesis is tested through self-consistent dynamical simulation based on an atomistically informed model of surface evolution in plasma-irradiated tungsten. Low-energy helium plasma irradiation of a tungsten surface, even when the ion energy is below the sputtering threshold, generates surface vacancy-adatom pairs in addition to adatoms from the flux of self-interstitial atoms to the surface resulting from the growth of high-pressure helium bubbles. Along with the stress-driven surface morphological instability as the primary driving force, preferential diffusion of these surface adatoms modulated by the associated Ehrlich–Schwoebel (ES) barriers, combined with the surface free energy anisotropy drive the anisotropic surface nanostructure growth. Simulation results for helium irradiation on W(100) show growth of pyramidal surface features, akin to experimental observations. This work confirms the hypothesis on the effect of tungsten surface crystallographic orientation on helium-ion-induced surface morphology changes, where surface mound formation is the outcome of a stress-driven surface morphological instability, while the anisotropic growth of the mounds is controlled by the ES-barrier-modulated anisotropic surface adatom diffusion and faceting of the mounds is controlled by the surface free energy anisotropy.

Identification of mode I fracture toughness in GFRP/Al and GFRP/Cu joints for structural batteries

Fiber metal laminates (FMLs) have been proposed as components of structural batteries, yet their elastic mismatch can lead to interface cracks, compromising structural integrity and both mechanical and electrochemical efficiency. To this end, the bonding between the metal and the composite layer is of utmost importance. In this study, the effect of various metal surface treatments on the mode I interlaminar fracture toughness of two FML configurations suitable for structural batteries — Glass Fiber Reinforced Polymer (GFRP)/aluminum laminate and GFRP/copper laminate — was examined. The surface treatments included sulfo-ferric etching, NaOH/HNO3 etching, and Sol–Gel anodizing for aluminum 2024-T3, as well as FeCl3/HCl/Glycerol treatment and Sol–Gel anodizing for copper alloy. The results were compared with untreated conditions and with the baseline GFRP/GFRP configuration. GFRP/metal coupons were designed to achieve pure mode I interlaminar fracture toughness in double cantilever beam (DCB) tests, and the designs were verified using the Virtual Crack Closure Technique (VCCT). The surface characterization of the metals was performed using contact angle tests to estimate the surface free energy, while Coherence Scanning Interferometry (CSI) was used to measure the surface roughness and topography.

Producing a siliceous ferroalloy from a mixture of amorphous rocks

The main silicon-containing component in a charge during ferrosilicon smelting is quartzite. The carbothermic reduction rate of the crystalline structure SiO2 has a limitation associated with a fixed energy reserve of silicon-oxygen bond. The reactive capacity of silica can be increased by using its amorphous form instead of the crystalline SiO2. The amorphous form of silica has a higher dispersion, greater free surface energy, and, consequently, a more active degree of entering into a reaction. Such silica-containing materials include amorphous rocks: diatomite, opoka, tripoli. The article presents the results of experimental studies of electrothermal ferrosilicon production from a mixture of amorphous rocks (tripoli, opoka, diatomite with a mass ratio of 1:1:1).It is established that when smelting the mixture of amorphous rocks containing 77 % SiO2, 7.9 % Al2O3, 5.2 % Σ CaO and MgO, 4 % Σ K2O Na2O, 3.3 % Fe2O3, 1.3 % CaCO3, 0.9 % CaSO4, 0.4 % others, three ferrosilicon grades are formed: FeSi25 (22–29 % Si), FeSi45 (41–47 % Si), FeSi50 (47–52 % Si) with the extraction degree of 70–87.6 % silicon into the alloy. Moreover, the ferrosilicon grade decreases with an increase in steel shavings in the charge from 21.9-31.4 % to 33–35 %. In comparison with ferrosilicon smelting from a standard charge containing quartzite with the crystalline form of SiO2, steel shavings and coke, ferrosilicon production from the mixture of amorphous rocks allows to increase the process rate by 17.5–21.6 %. It is possible to increase the silicon extraction degree into the alloy from 80-85 %–94.5 % if its final stage is carried out in the resistance mode. Widespread occurrence in nature, favorable conditions of occurrence, low cost, high reactive capacity are favorable factors for using amorphous rocks in the production of ferroalloys.

A Molecular Engineered Strategy to Remolding Architecture of RuP2 Nanoclusters for Sustainable Hydrogen Evolution

AbstractTransition metal phosphides (TMPs) are promising hydrogen evolution reaction (HER) electrocatalysts, but the unsatisfying activity and durability at industrial‐scale current densities hinder their application. Downsizing TMPs to nanoclusters can substantially enhance their activity; yet, the high surface free energy tends to initiate agglomeration thereby limiting their service life. Herein, a molecular engineering strategy to synthesize robust sulfur‐doped RuP2 (S‐RuP2) nanoclusters, which can continuously provide ampere‐level current densities of 1.0, 2.0, and 3.0 A cm−2 for at least 480 h with low overpotentials of 55.6 ± 1.0, 90.6 ± 1.2, and 122.8 ± 1.0 mV, respectively, is proposed. In particular, it exhibits a remarkable charge transfer amount (representing a long service life), outperforming all reported alkaline HER electrocatalysts. Remoulding the RuP2 architecture by sulfur atom can significantly lift the d‐band center of Ru and the p‐band center of P, therefore strengthening the adsorption of H2O, H, and OH to reduce the barriers of water dissociation and H migration. The authors‘ research unveils the enormous potential of molecule‐based porous materials for designing high‐performance nano‐structured catalysts.