Binary surfactant formulations can modify thin-film stability through non-additive changes in adsorption, interfacial mobility, and surface rheology. This study extends an electrical liquid-bridge method previously developed for single surfactants to binary systems containing sodium dodecyl sulfate (SDS), benzalkonium chloride (BAC), Ethylan 1005, sodium oleate, and polypropylene glycol 600 (PPG 600). Sixteen formulations were examined at fixed drainage rates of 10 and 20 µL h−1 using normalized apparent-conductance measurements synchronized with optical recording and TechDig contour reconstruction. Fifteen formulations formed measurable films at both rates, whereas 250 ppm SDS + 500 ppm sodium oleate (nominal mass–concentration ratio 1:2) failed by neck rupture before film formation. Binary mixtures either prolonged film lifetime relative to matched single-component references or enabled film formation where the reference was non-film-forming. Optical measurements independently supported the electrical ranking: longer-lived films generally reached smaller terminal neck diameters. The longest-lived formulation, 3000 ppm SDS + 500 ppm sodium oleate, also reached the smallest terminal neck. Pump-based mass balance and terminal bubble deformation further supported greater liquid removal and axial stretching before rupture. The combined electrical–optical approach provides a reproducible comparative framework for composition-dependent thin-film stabilization.
This paper investigated the lubricant stability and anti-biofouling performance on slippery liquid-infused nanostructured surfaces (SLIPSs) using thermodynamic and interfacial energy analyses. ZnO nanorods were synthesized on indium tin oxide substrates with and without a ZnO seed layer by electrochemical deposition and subsequently infused with PDMS-based silicone oil. The seed-layer-assisted growth produced densely packed and vertically aligned ZnO nanorods. Interfacial energy analysis showed that the resulting SLIPSs satisfied the criterion for resistance to water-induced lubricant displacement (ΔE2 = 64.14 mJ·m−2), indicating effective lubricant retention, whereas non-seeded surfaces exhibited reduced lubricant stability. Consistent with this prediction, the seed-layer-assisted SLIPSs retained droplet mobility following spin testing at 2500 rpm, although the reduced sliding velocity indicated a decline in slippery performance. Anti-biofouling evaluation using Escherichia coli (XL1-Blue) revealed that the SLIPSs effectively suppressed bacterial attachment, reducing surface coverage to below 0.3% after 24 h of incubation. In comparison, the pristine ITO and ZnO nanorods exhibited values of 50.8% and 54.6%, respectively. Subsequent surface free energy analysis demonstrated that lubricant infusion reduced the work of adhesion to 77.92 mJ·m−2. These findings provide insight into the interfacial interactions governing lubricant retention and bacterial attachment on SLIPSs.
Selective laser melting (SLM) and electron beam melting (EBM) enable the fabrication of commercially pure titanium, but the effects of the fabrication method and build orientation on surface characteristics and bonding remain unclear. This study evaluated the surface roughness, wettability, and shear bond strength of titanium fabricated by SLM and EBM at build orientations of 0°, 45°, and 90°, with titanium ingots intended for dental casting serving as reference specimens. The surfaces were wet-ground, air-abraded with 50 µm alumina particles, and treated with a 10-methacryloyloxydecyl dihydrogen phosphate-containing metal primer. Surface roughness (Sa), static water contact angles before and after primer application, and shear bond strength to a resin luting agent after 24 h of water storage were evaluated (n = 15/group). The EBM specimens fabricated at 90° exhibited significantly greater Sa values than the other groups (p < 0.05). Primer application significantly increased the water contact angle in all groups (p < 0.05), although group-dependent differences were observed. No significant differences in shear bond strength were detected among the fabrication conditions (p > 0.05). Thus, under the tested surface treatment conditions, differences in surface roughness and wettability were not accompanied by corresponding differences in the initial bond strength of commercially pure titanium.
Niobium-based catalysts have emerged as highly adaptable materials for reactions under heterogeneous conditions, owing to significant advances achieved in synthetic methodologies and characterization strategies. In this review, special attention was paid to analyzing the main methods used to characterize the physicochemical properties (e.g., gas adsorption/desorption, infrared spectroscopy, X-ray diffraction patterns, and temperature-programmed desorption) of solid niobium catalysts, as well as the most widely used and versatile synthesis methods (e.g., microwave-assisted solvothermal synthesis, impregnation, and mechanical milling). These insights can facilitate the rational design of Nb-based catalysts to achieve high activity and selectivity in biomass conversion processes and the valorization of biomass-derived compounds. The developments outlined here underscore the adaptability of niobium materials and provide a comprehensive basis for understanding the relationships between synthesis methodology and physicochemical properties, thereby supporting the development of more efficient Nb-based catalysts for sustainable catalytic applications.
Zoledronic compounds are widely used as antiresorptive and antitumor agents to prevent bone loss and treat multiple myeloma; however, their pharmacokinetic limitations motivate the search for alternative delivery systems capable of improving their controlled release and bioavailability. In this work, we investigate the stability, structural behavior, and adsorption properties of zoledronic acid (ZOL) and its Ca2+ and Zn2+ salts confined within the interlayer space of the smectite clay mineral montmorillonite by combining empirical force field (FF), density functional theory (DFT), and molecular dynamics (MD) simulations. The main objective of this study is to evaluate the suitability of montmorillonite as a potential drug delivery system (DDS). Specifically, crystal polymorph structures of zoledronic acid [1-(2-hydroxy-2-phosphonate-2-phosphonoethyl)-1H-imidazol-3-ium)] (ZOL) and its Ca2+ and Zn2+ salts were analyzed. Our calculated crystal structures obtained by both methods (FF and DFT) agree well with the known experimental data. Furthermore, the intercalation of ZOL into the confined interlayer space of montmorillonite is energetically favorable. Several interlayer cations (Na+, Ca2+, and Zn2+) were also evaluated. MD simulations showed that ZOL adopts stable confined configurations within the interlayer space of montmorillonite, exhibiting small torsions of the imidazole group. Additionally, the desorption of ZOL in a modelized acidic medium is energetically favorable. Our calculations predict that this clay mineral holds strong potential for the controlled delivery of zoledronic compounds.
In this short perspective, we analyze the different linear response functions relevant to surface diffusion studied by helium atom scattering, organizing them around a single object: the intermediate scattering function (ISF), which is also a characteristic function (CF) in the sense of probability theory. This organizing role of the CF is, to our knowledge, not made explicit elsewhere in the surface-diffusion literature, even though the time exponential function it predicts in the diffusive regime is a special case of the classical continuous-time-random-walk (CTRW) theory. Special emphasis is placed on this diffusive regime, established at times much greater than the inverse of the friction coefficient, where quantum features of the diffusion process are washed out. We show how the entire hierarchy of response functions—the after-effect function, the generalized susceptibility, the relaxation function, and the Green function—can be written directly in terms of the time moments of the ISF at $t=0$, and how the Pauli master equation and the Chudley-Elliott (CE) jump model follow as particular lattice realizations of a general compound-Poisson process. The extension to finite surface coverage is discussed within the interacting single adsorbate (ISA) model.
A technological approach to the formation of a 3D nanocomposition material based on hierarchical porous nickel oxide nanoparticles incorporated into porous silicon with a dendritic porous structure is proposed. Porous silicon was used as a 3D porous template, in the presence of which porous hierarchical nickel oxide nanoparticles were synthesized using a “green” synthesis method followed by annealing in an oxygen-containing atmosphere. The resulting materials were characterized using scanning electron microscopy, transmission electron microscopy, X-ray spectral microanalysis, X-ray diffraction, and the BET method. The potential of a developed composition based on porous hierarchical nickel and silicon oxide nanoparticles to enhance the sensitivity of adsorption gas sensors was assessed using impedance spectroscopy in the presence of a probe gas (isopropanol). Gas sensitivity measurements were conducted at room and elevated temperatures in the frequency range from 100 Hz to 500 kHz. Differences in the dependences of the real part of impedance on the imaginary part were revealed for the porNiO-porSi composition in Nyquist coordinates. The results are discussed in terms of percolation theory and fractal organization.
In the present study, the potential applications of Cu thin films and Ag/Cu bilayer thin films obtained by the pulsed laser deposition (PLD) technique are investigated in terms of the physicochemical effects resulting from their interaction with an aqueous solution containing Reactive Blue 21 (RB21) dye and sodium bicarbonate (NaHCO3). The thin-film deposition process was carried out using a Q-switched Nd:YAG laser system operating at a wavelength of λ = 532 nm, with a pulse duration of τ = 10 ns, a repetition rate of ν = 10 Hz, a pulse energy of E = 180 mJ, a laser spot diameter of d = 336 μm, and an angle of incidence of α = 45°. Two types of thin films were prepared: a Cu thin film and an Ag/Cu bilayer thin film. The thermal effects induced by the interaction of the laser beam with the target materials were investigated by numerical simulations performed in COMSOL, allowing the evaluation of melt-phase formation for each material separately and providing a better understanding of the morphology and topography of the deposited thin films. The simulation results were validated through scanning electron microscopy (SEM) observations and surface roughness analyses. The two thin films were subsequently treated with an aqueous solution containing 10 g/L RB21 dye and 10 g/L NaHCO3. Physicochemical analyses performed after treatment, including scanning electron microscopy (SEM), optical microscopy (OM), profilometry, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and UV–Vis spectroscopy, revealed significant degradation of the RB21 dye accompanied by corrosion of the thin films, with the corrosion process being more pronounced in the case of the Cu thin film. The obtained results indicate that the method analyzed in this study may represent an alternative approach for the decomposition of recalcitrant organic dyes using thin Cu films, without relying on conventional photocatalytic processes. Equally important are the potential applications of the RB21/NaHCO3 solution as an etching and patterning medium for thin Cu layers, while the Ag overlayer may provide a protective effect during such processes. These findings may contribute to the development of novel fabrication techniques for optoelectronic components, including solar cells, photovoltaic windows, and other industrial and laboratory applications.
Polyetheretherketone (PEEK) has emerged as a promising biomaterial for orthopedic and craniofacial implants due to its favorable mechanical properties and fatigue resistance; however, its inherent chemical inertness limits effective osseointegration. In this study, femtosecond laser surface modification is explored as a strategy to enhance the bioactivity of PEEK. Based on a previously performed parametric study, controlled micro- and nanoscale surface textures were fabricated using femtosecond laser processing, enabling precise tuning of surface roughness and wettability without the need for additional chemical treatment. The modified surfaces were systematically characterized in terms of morphology, composition, and topography using scanning electron microscopy (SEM), 3D profilometry, and water contact angle measurements. Four optimized femtosecond laser-generated surface architectures were selected for the present investigation and comprehensively characterized, followed by in vitro evaluation of dental pulp stem cell adhesion, morphology, and proliferation. The results indicate that laser-induced micro/nanostructuring enhances the surface properties of PEEK, while supporting cellular attachment and favorable cell–surface interaction. Differences in the biological response were observed among the optimized laser-textured surfaces. These findings highlight the feasibility of femtosecond laser texturing as a clean, reproducible, and scalable approach for the development of next-generation, personalized orthopedic implants.
Flexible implantable electrodes require biocompatibility, mechanical stability, and sufficient electrical conductivity for effective neural interfacing. This work examines ultrasonic treatment during poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) impregnation of electrospun poly(D,L)-lactide (PLA) nonwoven scaffolds as a route to improve filler distribution and functional performance. Four sample types were studied: pristine PLA (untreated and sonicated) and PLA–PEDOT:PSS composites prepared with and without ultrasonication. Scanning electron microscopy shows that ultrasonic treatment suppresses the formation of continuous surface films and promotes homogeneous three-dimensional penetration of PEDOT:PSS throughout the fibrous network. As a result, electrical resistivity decreases by a factor of 7.3, from 294.4 to 40.2 Ω·m. Contact-angle measurements reveal markedly enhanced wettability, with sonicated composites exhibiting rapid water uptake (5–13 s), unlike non-sonicated controls. These findings demonstrate that ultrasound-assisted PEDOT:PSS impregnation yields conductive, highly wettable, and structurally stable scaffolds, highlighting their potential for flexible implantable neural electrodes.
We performed a theoretical analysis (the PBE-D2/DNP level of the density functional theory with the use of the DSPP pseudopotentials) of the geometries, bonding and frontier orbital energies, spin and charge distribution for the entire series (from La to Lu) of lanthanide atoms interacting with Ih−C80 cage, for both η5 and η6 exohedral coordination patterns. In certain regards, the exohedral η5 and η6 coordination of Ln atoms to the C80 fullerene cage exhibits similar qualitative and semi-quantitative trends (the bonding strength, shortest Ln…C distances, charge and spin of lanthanide atoms). The most interesting aspect is the molecular spin of the complexes, where we observed different patterns of ferromagnetic and antiferromagnetic coupling. Three complexes represent an extreme, when the antiferromagnetic coupling results in zero or close-to-zero molecular spin. In some cases, the molecular spin is a simple sum of 2 e of the isolated C80 cage and the spin of an isolated Ln atom. However, the most common situation is when another 2 e spin adds: it is best illustrated with Eu (spin of 7 e for the atomic ground state), where the molecular spin of its η5 and η6 complexes is not about 9 e but reaches almost 11 e.
Structural materials in nuclear energy, aerospace, and electronics face long-term irradiation by high-energy particles, triggering microscopic defect evolution and macroscopic performance degradation that limits service safety. This review provides a systematic overview of irradiation damage mechanisms, with particular emphasis on the role of surfaces. The discussion traces the evolution from initial defect generation through energy deposition and displacement cascades to the migration and aggregation of defects toward surfaces, culminating in their interactions with near-surface microstructures. A comparative analysis of damage behaviors in metals, ceramics, silicon-based materials, and polymers is presented, elucidating how distinct mechanisms arise from fundamental differences in crystal structure and chemical bonding. The integration of multiscale simulation techniques with advanced in situ characterization is highlighted as a critical approach for deciphering the cross-scale processes. Current strategies for enhancing radiation resistance including composition optimization, microstructure regulation, and interface design are summarized. Finally, the review outlines key challenges such as multi-field coupling damage characterization and long-term predictive modeling. Future research directions are foreseen to emphasize closer simulation–experiment integration and the design of smart, self-adapting materials, thereby providing comprehensive theoretical and technical support for the development of next-generation radiation-tolerant materials.
Three-dimensional (3D) epicuticular wax coverage on plant surfaces contributes to multifunctional surface properties, such as enhanced water repellence, reduced pathogen adherence, modified optical properties, and reduced insect adhesion. The diversity in wax projection morphology, size, abundance, and spatial arrangement among plant species results in a broad spectrum of anti-adhesive effects, reflecting both phylogenetic history and ecological function. This study presents a numerical model consisting of 3D tubular-shaped structures randomly deposited on a substrate and forming a highly porous layer. The simulations based on this model demonstrate a strong reduction in adhesion to the contacting insect adhesive pad. It is found that a structure formed by sufficiently long tubes, where the length is enough to support the tubes in space and build a porous 3D structure with a very low density, at relatively weak attraction to the underlying substrate, leads to the weakest adhesion. The model is constructed on the basis of our recent works combining discrete and continuous approaches in biological modeling. It mainly exploits the technique of the movable digital automata, allowing modeling of numerous numerically elastic cylinders that can be moved in 3D space, elastically collide with one another and with boundaries, and build self-consistent surface structures, which can be used to mimic nano- or microscale surface coverages of real plants.
This study investigates the formation mechanism of lactic-acid-derived coatings produced by open-air atmospheric-pressure plasma polymerization. A comparison of nebulization and bubbling precursor-delivery methods using FT-IR and XPS showed that the bubbling method facilitated plasma-assisted chemical bonding, including the possible formation of copper(II) lactate-like interfacial species and the retention of carbonyl-containing functional groups. However, the present dataset does not provide direct, discriminating evidence for a specific metal-lactate interfacial species, and alternative interpretations such as adsorption, oxidation, hydroxylation, or generic oxygenated carbon deposition cannot be excluded. Time-dependent analysis revealed a transition from oxygen-rich functional layers at short plasma exposure to carbon-rich overlayers at longer exposure, suggesting a fragmentation-recombination mechanism that is consistent with the formation of a metal-lactate-like interfacial region and a carbon-rich overlayer, while alternative interpretations related to signal attenuation and non-uniform coverage remain possible. Antibacterial testing revealed that the observed bacterial responses were not attributable to an intrinsic antibacterial property of the deposited films, but were instead strongly dependent on the underlying substrate chemistry and exposure time. C1100 retained the inherent antibacterial activity of copper, SUS430 showed no activity due to the absence of film formation, and SPCC exhibited only a transient effect attributed to lactic-acid-induced local acidification. Overall, the study elucidates the plasma-assisted deposition mechanism of lactic-acid-derived coatings under open-air conditions and highlights the critical role of interface chemistry in achieving stable and substrate-independent functional properties.
This study investigates the inhibitory effects of alkali metal chlorides lithium chloride, sodium chloride and potassium chloride (LiCl, NaCl, and KCl) on sodium dodecyl sulfate (SDS) foams, focusing on the transition from interfacial to bulk-driven destabilization mechanisms. The research demonstrates that foam collapse at high electrolyte concentrations is governed by a massive increase in bulk cohesive pressure and specific ion-pairing (SIP), which leads to interfacial dehydration and the mechanical decoupling of the surface from the bulk phase. It is shown that while surface adsorption reaches a plateau, the thermodynamic state of the solvent becomes the primary driver for film drainage. The results indicate that KCl acts as the most potent defoamer due to its optimal matching of water affinities with the surfactant head groups. These findings provide a new theoretical framework for understanding foam stability in concentrated electrolytic environments, emphasizing the role of bulk cohesive stress over traditional interfacial elasticity.
Green synthesis of metal oxide nanoparticles (NPs) offers an eco-friendly, cost-effective alternative to conventional chemical and physical methods, minimizing energy use and hazardous reagents. This study demonstrates the biogenic production of manganese oxide (MnO) NPs using Catharanthus roseus flower extract as a reducing and capping agent, Comprehensive characterization via FTIR (Mn–O vibrations at 591–405 cm−1 along the capping groups), XRD (confirms the cubic crystalline phase), FESEM (flaky, agglomerated sheets), EDX (Mn 62.37%, O 28.40% and C 9.23%), zeta potential (−0.3 mV), and TGA (33.7% phased mass loss to 985 °C) verified pure and stable MnO NPs. In vitro assays on L929 fibroblasts revealed dose-dependent MTT cytotoxicity (78.77% viability at 20 µg/mL to 39.97% at 100 µg/mL) yet enhanced scratch wound closure (−16.31% area reduction vs. −17.41% control), alongside potent antibacterial activity with highest inhibition zones of 15 mm against Klebsiella pneumoniae and Escherichia coli, and lowest of 4 mm against Pseudomonas aeruginosa at 40–100 µg/mL. These multifaceted properties highlight C. roseus-assisted MnO NPs’ promise for wound healing and antimicrobial applications, warranting dosage optimization and in vivo studies.
Boron coatings were deposited by RF magnetron sputtering in an Ar atmosphere at a constant power of 80 W, varying the working pressure in the 0.6-5 Pa range. Plasma diagnostics were performed by means of a Langmuir probe to determine the electron temperature and electron density under different operating conditions. Within the investigated pressure range, the deposition rate remained nearly constant, whereas a significant decrease in coating mass density was observed with increasing pressure. The coatings display a columnar structure at all investigated pressures, with no significant differences in bulk morphology. Pressure primarily affects the surface features, leading to an increase in the density, lateral dimensions, and height of surface agglomerates with increasing pressure. Compositional analysis by EDX revealed a substantial oxygen incorporation in the films, with the lowest oxygen content (similar to 11 at.%) measured for the coating deposited at 0.6 Pa. XPS depth profiling confirmed the presence of oxygen and evidenced the formation of boron oxide species, while the boron concentration exceeded 80 at.% in all samples. These results highlight the strong sensitivity of boron film density and oxygen uptake to sputtering pressure.
Cellulose ether, like hypromellose (HM), is an extremely versatile material that is widely used in pharmaceutical products as film coatings. To modify the surface properties of HM films, additives are routinely included during the film formulation process, which are typically hydrophobic lubricants or hydrophilic plasticizers. Plasticizers increase the flexibility and reduce the brittleness of the film. The first goal of this study is to demonstrate that plasticization of HM films by low-molecular-weight (400 g∙mol−1) polyethylene glycol (PEG) allows tuning adhesion and friction properties of HM films, both at nano- and macroscales. Surface morphology, surface energy, nano/macro adhesion, and nano/macro friction coefficient were studied by atomic force microscopy (AFM) in adhesion or friction modes at the nanoscale, wettability, and probe-tack adhesion, as well as pin-on-disk friction experiments at the macroscale. The results show that the addition of PEG decreases the Young’s modulus and the Tg of HM-plasticized films while increasing their strain at break and surface energy. The macroadhesion force increases from 9 to 90 mN by the addition of 40% w/w of PEG, whereas the macrofriction coefficient is reduced by 50%. The hypothesis of insertion of plasticizer molecules in HM chains’ nano-domains is evidenced and explains these results. The second goal of this study is to investigate nanoscale versus macroscale correlation of adhesion and friction properties and the role of adhesion in friction experiments. The results show, first, that the evolution of the adhesion energy at the macroscale as a function of adhesion energy at the nanoscale is linear. On the contrary, a high friction coefficient at the nanoscale corresponds to a low friction coefficient at the macroscale and vice versa, showing a first linear decrease for PEG contents ranging from 0 to 30% (w/w) and the second linear decrease, less pronounced, is observed for PEG contents ranging from 30 to 40% (w/w). The hypothesis of a difference in contact pressure applied on the probe at both scales, as well as HM-PEG surface phase separation at a high PEG content (>30% w/w), is proposed to explain this difference. The variations in friction coefficients are linear according to the PEG plasticizer content and suggest its lubricant role in HM-Plasticized films. Finally, the interplay between adhesion and friction, in friction experiments, is evidenced and appears dominant at the nanoscale.
The quasi-steady low-Reynolds-number flow induced by a linear chain of multiple slip spheres translating along their common axis in a Newtonian fluid is investigated. The particles are allowed to differ in radius, Navier slip coefficient, migration velocity, and interparticle spacing. A semi-analytical solution of the governing Stokes equation is obtained using a boundary collocation method. Hydrodynamic interactions among the particles are shown to be significant under appropriate geometric and surface conditions. For the two-sphere configuration, the computed hydrodynamic forces agree closely with previously published asymptotic solutions derived via the twin multipole expansion method. In the three-sphere case, the presence of a third particle substantially modifies the forces acting on the other two, demonstrating non-negligible many-body interaction effects. The interaction strength is found to be more pronounced for smaller particles or those with lower slip coefficients. Calculations for longer particle chains further reveal a clear hydrodynamic shielding effect within the assembly.
The increasing accumulation of poly(ethylene terephthalate) (PET) waste poses a significant environmental challenge and highlights the need for sustainable, value-added recycling strategies. In this study, porous carbon derived from PET was synthesized via carbonization and chemical activation and subsequently combined with manganese dioxide (MnO2) to fabricate hybrid electrodes for aqueous supercapacitors. The PET-derived carbon exhibits a highly microporous structure with a large specific surface area and functions as a conductive and mechanically stable matrix that improves MnO2 dispersion, charge transport, and electrochemical utilization. Systematic electrochemical investigations reveal strongly electrolyte-dependent charge-storage behavior. In an alkaline electrolyte, the capacitance is dominated by MnO2 pseudocapacitive redox reactions, whereas in a neutral electrolyte, the response is primarily governed by electric double-layer charge storage. In a ferricyanide-containing redox-active electrolyte, additional electrolyte-mediated faradaic processes significantly enhance the apparent electrochemical performance. Under these conditions, the hybrid electrodes deliver a high apparent specific capacitance of 240–250 F g−1 at moderate current densities. The electrodes further demonstrate stable cycling behavior and high apparent Coulombic efficiency, reflecting time-dependent utilization of both MnO2 pseudocapacitance and redox-active electrolyte species during charge–discharge. Crucially, this work demonstrates that PET-derived carbon/MnO2 hybrid electrodes exhibit complex, electrolyte-controlled charge-storage mechanisms and underscores the critical role of electrolyte selection in accurately interpreting electrochemical metrics and optimizing the performance of sustainable supercapacitors based on recycled polymer-derived carbons.
