This study investigates the degradation of perfluorooctanoic acid (PFOA) in aqueous solution using an air-operated multi-pin over liquid dielectric barrier discharge reactor (DBD). PFOA concentration decreased during the initial treatment stage but reached a plateau after approximately 30 min (25 kWh m-3), indicating limited further conversion. Total organic carbon (TOC) declined slowly, suggesting progressive oxidation of transformation products rather than continued PFOA degradation. Fluoride release of less than 1% indicated limited mineralization. Energy yield decreased with time, indicating kinetic saturation. A broader distribution of transformation products was revealed in coupling tests with activated carbon, indicating an influence on plasma-induced transformation pathways. Nevertheless, these findings show that air-fed DBD plasma exhibits inherent limitations for PFAS oxidation under the experimental conditions investigated.

In this work, the effect of femtosecond laser-induced structuring on the morphological, structural and chemical properties of an AlCuTiZnZr metallic glass thin film deposited by magnetron plasma sputtering was studied. The deposition conditions were selected to produce an alloy containing > 50 at % of bactericidal elements (Cu and Zn). The as-deposited and laser structured films were characterized by SEM, AFM, EDX, XPS, RBS, GIXRD and TEM. The impact of the laser induced structuring on the bactericidal activity was assessed against Escherichia coli. Results showed that laser induced structuring led to the formation of Low Spatial Frequency LIPSS (Laser Induced Periodic Surface Structures) on the alloy thin film with periods of 650 +/- 20 nm and an amplitude of 400 +/- 50 nm. A partial ablation of the film was evidenced inducing a drastic modification of the surface chemistry due to the re-deposition of ablated atoms. A crystalline, oxidized, poorly adhesive layer enriched in bactericidal elements was formed covering the surface. TEM observations clearly showed that nano-patterns of unaffected metallic glass are still present at the top of the LIPSS, below this redeposited layer. In the presence of this upper layer, an increase of the bactericidal activity was highlighted as compared to the as deposited stable metallic glass film. This was correlated to a rise in the copper and zinc ion concentrations in the solution after interaction with the structured surfaces, as measured by ICP-OES. These findings suggest that laser-induced structuring could promote the release of ions while preserving the presence of amorphous phase nano-ptterns present beneath the redeposited layer. This could lead to surfaces that combine enhanced bactericidal activity with metallic glass properties.

Thermal expansion is an intrinsic property of metals and alloys, posing a critical challenge for achieving dimensional stability in lightweight systems where low atomic mass enhances lattice vibrations. Here, we present a strain recovery compensation strategy that achieves three orders of magnitude reduction in thermally induced volume change, enabling zero thermal expansion (ZTE) in a rare-earth magnesium alloy containing 1.2 vol.% Al-stabilized MnCoGe particles. The coefficient of thermal expansion is reduced from 28 × 10⁻⁶ °C⁻¹ to 0.02 × 10⁻⁶ °C⁻¹ over 25-150 °C-the highest thermal stability reported for any alloy. This alloy also retains high compressive strength (424 MPa), ductility (12%), and ultralow density (1.93 g/cm³). The ZTE behavior arises from sustained compressive strain, maintained by reversible martensitic transformation of the embedded particles. Beyond realizing a dimensional stable lightweight alloy, this work establishes a generalizable principle for achieving thermal dimensional stability in metals via recoverable strain.

The synthesis of thin films and coatings constitutes a cornerstone of modern materials science, underpinning technologies ranging from semiconductor logic gates to tribological barriers and catalytic membranes. Over the last decades, the need for precise control over film microstructure has driven a transition towards highly energetic processes, such as High Power Impulse Magnetron Sputtering (HiPIMS), and chemically complex methods like Atomic Layer Deposition (ALD) and solution-based processing. While continuum models effectively classify growth regimes based on macroscopic parameters, they inherently lack the resolution to describe the discrete atomic assembly processes—nucleation, island coalescence, and defect formation—that define functional performance. This review presents a comprehensive survey of Molecular Dynamics (MD) simulations applied to thin film growth. We detail the evolution of interatomic potentials, from classical descriptions (EAM, Tersoff) to reactive force fields (ReaxFF) and emerging Machine Learning Potentials (MLIP). The review critically analyzes MD contributions to understanding both organic systems (plasma polymers, self-assembled monolayers, solvent evaporation) and inorganic coatings (metals, complex oxides, high-entropy alloys). We demonstrate how MD bridges the gap between plasma physics and materials engineering, offering predictive scaling laws for density, intrinsic stress, and roughness. Furthermore, we address the timescale limitations of classical MD by reviewing hybrid multiscale frameworks coupling MD with Kinetic Monte Carlo (KMC) and Finite Element Methods (FEM), and highlight emerging applications in energy storage (solid-electrolyte interphase) and biomedical interfaces.

This study explores the performance of octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) coatings on SiO2 substrates through molecular dynamics (MD) simulations and experimental validations. MD simulations at 300 K investigated the molecular packing, wettability, and droplet dynamics of OTS SAMs across varying coverage densities (0.18 to 3.48 molecules nm-2). Results indicate that monolayer thickness increases from 0.3 to 2.4 nm with coverage density, while contact angles rise from 0° to 132.7°, with a peak at 125.2° due to surface roughness of 0.262 nm at 1.80 molecules nm-2. Rolling friction decreases as droplet velocity rises from 4.894 to 41.291 m/s, and self-driven droplet jumping at medium and high coverage enhances self-cleaning. Experimentally, OTS-coated wind turbine blade composite samples delayed icing to 649 s and complete icing to 725 s at -10 °C, compared to 12 and 17 s for SiO2 hydrophilic coatings, and 92 and 121 s for uncoated surfaces, attributed to reduced contact area and low surface energy. Deicing tests showed OTS coatings achieve ice detachment in 58 s on tilted surfaces via a lubricating water layer, despite longer melting times of 215 s on horizontal surfaces. These findings highlight OTS SAMs' superior hydrophobicity, low friction, and anti-icing/deicing performance, offering potential for high-altitude engineering applications.

This work establishes a protocol to study via Molecular Dynamics simulation the degradation of Per-and Polyfluoroalkyl Substances (PFAS) in water by hydroxyl radical. To achieve this, molecular dynamics simulations are carried out, using ReaxFF reactive interaction potential. Simulations are carried out under a temperature ramp for determining all possible products. Using this methodology, reaction pathways of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are identified.

The C4F7N/CO2/O-2 ternary gas mixture, with its excellent environmental and insulating properties, has emerged as one of the most promising alternatives to SF6 and has seen initial applications in global power systems. Currently, there is limited research on the stability of C4F7N/CO2/O-2 in equipment under long-term operation with micro-water content. This study uses reactive molecular dynamics simulations, using ReaxFF forcefield, to investigate the effect of water (up to 2%) on the thermal decomposition characteristics of C4F7N/CO2/O-2 at the microscopic level. Additionally, thermal decomposition experiments of C4F7N/CO2/O-2 under different micro-water concentrations were conducted to analyze the relationship between decomposition products and micro-water content. When the micro-water concentration is below 1.6%, H2O promotes the generation of O radicals, increasing the decomposition of C4F7N. However, as the H2O concentration increases further, the large amount of generated OH radicals consumes O radicals, inhibiting the main decomposition reactions of C4F7N. Experimental results show that the main thermal decomposition products of the gas mixture are CF4, C3F8, C3F6, C2F6, and CHF3. The findings of this study provide theoretical support and technical foundation for enhancing the reliability of C4F7N/CO2/O-2 insulation equipment in long-term engineering applications.

For understanding and controlling film growth parameters of various sputtering deposition conditions, molecular dynamics simulations are carried out to describe Tantalum Nitride conventional Magnetron Sputtering and High Power Impulse Magnetron Sputtering (HiPIMS) film growth and structure. It includes full atomic and ion energy distribution for a realistic account of experimental conditions, notably for HiPIMS deposition technique. Results are well compared with available experimental results in the literature, demonstrating that the present method is well suited for a very broad set of experimental conditions. The effect of the sputtered ion to neutral ratio on the film crystallographic structure is addressed using simulated X-ray diffraction and polyhedral template matching methods. It is shown that hcp phase predominates at moderate ion flux, and always coexists with fcc phase. The present molecular dynamics simulations, are therefore a powerful tool for correlating the predicted thin film structure to experimental conditions.

Sputtering of cobalt, silicon and zirconium in a helium magnetron discharge (MS) is reported as a bottom-up procedure to obtain He-charged films (i.e. 4He and 3He filled nanopores encapsulated in the matrix material). Composition and microstructural analyses are presented from ion beam analysis (IBA) and scanning and transmission electron microscopies (SEM and TEM). Helium desorption was investigated by IBA in a dedicated chamber for "in situ" thermal evolution in vacuum. The simultaneous recording of the helium and matrix-element signals shows different behaviors of the different matrix elements (i.e. Co, Si and Zr) and deposition conditions (i.e., DC or RF discharge modes and dynamic or quasistatic vacuum). Effusion, blistering, delamination and flaking have been observed for the different samples leading to the formation of nano-porous/nanostructured thin films. The methodology is being envisaged as a process for nanostructured thin-films fabrication with potential applications.

In this work, we evaluated the ability of three numerical methods to predict the phase formation in Cu–Zn binary and Cu–Ti–Zn ternary alloy thin films deposited by DC-magnetron sputter deposition. Molecular dynamics (MD) simulations were carried out to simulate the growth of the alloy film and study the organization at the atomic level. A Machine Learning (ML) approach trained with a recently published bulk HEA (high-entropy alloy) database was used to determine the presence of an amorphous phase, solid solutions, or/and intermetallics. Finally, CALPHAD (CALculation of PHAse Diagrams) thermodynamic modeling allows one to simulate the phase diagrams. Crystalline phases formed in experimental films were investigated by grazing incidence x-ray diffraction (GIXRD). Comparison with CALPHAD results highlights that for pure Ti or binary Cu–Zn films, the thermodynamically stable phases are formed in the films. Less agreement was found at low or high percentage of Ti introduced in the Cu–Zn system, and drastic differences were observed for elemental compositions close to equimolarity. In those cases, the out of equilibrium nature of the magnetron sputtering deposition technique is evidenced. The very limited agreement between the GIXRD and ML approach is explained by the available database, which is exclusively based on bulk alloys. Elemental composition of the alloy does not itself determine the stabilized phases: elaboration techniques are to be taken into account too. MD simulations bring information on a possible segregation of the Zn element to the surface and grain boundaries. A very good agreement is evidenced between the calculated and experimental diffraction patterns.

The Non-Thermal Plasma (NTP) process was studied for the removal of pharmaceutical pollutants (diclofenac (DCF) and carbamazepine (CBZ)) from water. In the individual treatment, at 0.2 W, showed 86% DCF and 63% CBZ degradation in 40 min, forming hydroxylated and nitro-products. The same degradation efficiency was achieved for each compound in the mixed pollutant systems, and a complete degradation was attained after 90 min. By comparing the intermediate products, the formation of nitro-products was higher in the mixed systems compared to their individual solutions treatment. The study concluded that NTP efficiency should be evaluated on pollutant mixtures rather than single compounds. Complementary biological analyses revealed the potential cell toxicity induced by generated products, highlighting the pertinence for toxicological analyses.

Atmospheric pressure helium plasmas are investigated through molecular dynamics simulations at room temperature (300 K) for various ionization fractions (χ_{i}=10^{-1}-10^{-5}) in the strongly coupled regime (ion coupling parameter, Γ_{i}∼1-10) employing Coulomb and Yukawa interaction potentials. The role of electron screening in ion dynamics and energetics is examined through ion and gas temperatures, mean squared displacement of ions, ion coupling parameter, and radial distribution function of the system. It is found that electron screening in the Yukawa potential significantly limits the disorder-induced heating (DIH) mechanism for strongly ionized plasmas (χ_{i}≥10^{-3}). Whereas, ions show a prominent subdiffusive behavior associated with the DIH during the nonequilibrium phase for the Coulomb potential. The DIH mechanism is explained using a model based upon the conservation of energy. However, for weakly ionized plasmas (χ_{i}≤10^{-4}), the maximum ion temperatures are almost similar for both potentials. Furthermore, electron screening affects the separation distance and arrangement of the ion-neutral pairs for all the values of χ_{i}. In general, Yukawa potential results in a lower mean potential energy of the interacting particles, which is energetically favorable for the stability of the system.

The detailed mechanism of bonding in the cold spray process has remained elusive for both experimental and theoretical parties. Adiabatic shear instability and hydrodynamic plasticity models have been so far the most popular explanations. Here, using molecular dynamics simulation, we investigate their validity at the nanoscale. The present study has potential applications in the fabrication of ultrathin layers in the electronics industry. For this aim, we considered Ti nanoparticles of different diameters and Si substrates of different orientations. It is shown that very high spray velocities are required for a jet to be observed at the nanoscale. We propose a method for thermostating the substrate that enables utilizing high spray velocities. For the first time, we demonstrate an oscillatory behavior in both the normal and radial stress components within the substrate that can propagate into the particle. We have shown that neither the adiabatic shear instability model nor the hydrodynamic plasticity model can be ignored at the nanoscale. In addition, the formation of a low-resistance titanium silicide proper for electronic application is illustrated.

Describing the activation of O2 on metal surfaces is crucial for understanding fundamental electrochemical processes, such as the oxygen reduction reaction (ORR) in hydrogen fuel cells. This study explores how defects influence O2 adsorption mechanisms on a zirconia-based cathode. In the first step, we model O2 adsorption on two defective surfaces: oxygen-deficient t-ZrO2-x and oxynitride t-ZrO2-x N x , in an aqueous solution. We describe various O2 adsorption states by analyzing charge transfer and cohesive energy changes in O2 molecules, Zr active sites, and defects. The results suggest that O2 adsorption mechanisms on the surfaces of t-ZrO2-x and t-ZrO2-x N x occur through dissociative and associative pathways, respectively. Additionally, O2 adsorption on t-ZrO2-x N x leads to the departure of N dopants from the surface, which is unfavorable for catalytic activity. In the second step, we modified the surfaces of t-ZrO2-x and t-ZrO2-x N x with the hydroxyl (OH) group. Afterward, we simulate the O2 activation process on these modified surfaces and identify the most probable active sites. Our findings reveal that OH groups stabilize N dopants on hydroxylated t-ZrO2-x N x , preventing their loss. Moreover, OH groups influence the O2 adsorption mechanism on t-ZrO2-x , shifting toward associative O-O bond breaking. Conversely, O2 adsorption on hydroxylated t-ZrO2-x N x remains molecularly associative. Overall, on hydroxylated surfaces, O2 adsorption involves stronger charge transfer among oxygen, defects, and Zr active sites. In the third step, we explored the trends of desorption of the O2 from these surfaces. This entails analyzing O2 desorption using steered molecular dynamics (SMD) to generate potential mean force (PMF) profiles and applying Jarzynski's equality to calculate the free energy of desorption. Herein, we find that the free energy of the desorption of O2 from hydroxylated surfaces is lower, indicating a more spontaneous process compared to t-ZrO2-x and t-ZrO2-x N x . Moreover, we discover that oxygen has the highest tendency to desorb from the hydroxylated-ZrO2-x surface, which is attributed to the lowest free energy involved in pulling oxygen from the surface, potentially influencing ORR acceleration. These findings offer valuable guidance for developing efficient nonplatinum-based cathode materials, particularly in catalysis applications.

This paper proposes a novel method to realize the partial discharge (PD) localizing function of gas sensors in GIL. Firstly, the diffusion characteristics of decomposition products were studied. The Fuller-Schettler-Giddings model was corrected to obtain decomposition products’ diffusion coefficients in high-pressure SF 6 . The finite element method (FEM) calculated the temperature rise, convection, and diffusion of decomposition products in GIL. With the relationship between the concentration variation and positions, a PD defects location method was proposed. The results indicate that the decomposition products would diffuse rapidly in the radial direction with the convection. Gas diffusion at the top of the GIL was faster than that at the bottom. Hence, the gas sensors were suggested to be set at the top of GIL. The axial diffusion was much slower and mainly affected by the temperature and diffusion coefficient. For a long GIL unit, the diffusion of decomposition products could be simplified to one-dimensional. In diffusion, the delay of the product concentration is negatively correlated with the square of the distance. That quantitative relationship could be used for localizing PD by the concentration increase delay detected by the sensors on both sides of the defect. The localization error would decrease with the increase of diffusion coefficient (rate) and prolonged monitoring (diffusion) time. The accuracy of the localization would also increase when the defect is close to the midpoint of the sensors.

Accelerating the oxygen reduction reaction (ORR) is a main subject of electrocatalysis research.A critical step of ORR is the formation of the hydroperoxyl functional group (OOH*) intermediate. In this study, we investigate the influence of defects on facilitating the creation of OOH* in a zirconia-based cathode under hydroxyl group (-OH) adsorption. Simulations involve tetragonal pristine ZrO2 (111) surfaces with introduced oxygen vacancy (t-ZrO2-x) and nitrogen dopant (ZrO2-xNx). Density functional theory (DFT) is used to calculate the competitive -OH adsorption energies on pristine and defective surfaces. It reveals that oxynitride t-ZrO2-xNx and under-stoichiometric oxide t-ZrO2-x exhibit the lowest and highest susceptibility to -OH adsorption, respectively. Additionally, we have determined the Minimum Energy Pathway (MEP) for OOH* formation on t-ZrO2, t-ZrO2-x, and t-ZrO2-xNx with adsorbed-OH using the Nudged Elastic Band (NEB) approach with the COMB3 potential. Our results highlight the significant influence of defects on tuning the barrier energy of OOH* formation. The trend in the barrier energy formation of OOH* decreases in the order of t-ZrO2-x > pristine t-ZrO2 > t-ZrO2-xNx. We demonstrate that ZrO2-xNx is a promising candidate for accelerating ORR due to its lower barrier energy for OOH* creation. The findings from this study offer crucial insights for experimentalists aiming to develop optimal non-platinum-based cathode materials.

Molecular dynamics simulations are carried out for calculating the surface loss probabilities of neutral species from an argon–methane plasma. These probabilities are the sum of the sticking and surface recombination probabilities. This study considers both the formation of reactive and nonreactive volatile species for evaluating recombination probabilities. Results show that stable species are reflected when hydrocarbon film starts growing on the surface. CH 3 is mainly lost by surface recombination leading to the formation of volatile products while very little contributes to film growth. C 2 H has surface loss probability in agreement with the literature. While C 2 H loss is usually attributed to sticking on the surface, our results show that its main loss process is due to surface recombination.

Carbamazepine (CBZ) is a pharmaceutical compound detected in various water resources. With a view to removing this contaminant, the applicability of non-thermal plasma (NTP) oxidation process has been widely tested in recent years. This study utilized NTP from a dielectric barrier discharge reactor in the treatment of CBZ. NTP on the surface of a water sample containing 25 mg.L−1 of CBZ resulted in a removal efficiency of over 90% with an energy yield of 0.19 g. (kWh)−1. On the other hand, a rapid reduction in pH and an increase of conductivity and nitrate/nitrite ions concentration were observed during the degradation. The applied voltage amplitude significantly affected the removal efficiency and the energy yield as the degradation efficiency was 55%, 70%, and 72% respectively with an applied voltage of 8, 10, and 12 kV. The water matrices containing inorganic anions such as chloride and carbonate ions reduced the removal efficiency by scavenging the reactive species. Accordingly, a reduction in the removal efficiency was observed in tap water. The high-resolution mass spectrometry (HRMS) results revealed that both reactive oxygen and nitrogen species take part in the reaction process which yields many intermediate products including aromatic nitro-products. This study concluded that NTP can effectively degrade CBZ in both pure and tap water, but special attention must be paid to changes in the water quality parameters (pH, conductivity, and nitrate/nitrite ions) and the fate of nitro products.

Molecular dynamics simulations were performed to investigate the growth of hydrocarbon films with a surface at temperatures from 300 to 1000 K. The results show that C2H is the main precursor of film growth. The formed C:H films are mainly unsaturated and dominated by double bonds and CN3 carbon atoms. The evolution of the C:H film is considered under the bombardment of the two major ions (Ar+ and C2H3+) with energies ranging from 50 to 100 eV. Film sputtering is significant above 50 eV, while at lower energies, the atoms of the C2H3+ ions can be incorporated and contribute to the growth.

We present a comparative study of copper film growth with a constant energy neutral beam, thermal evaporation, dc magnetron sputtering, high-power impulse magnetron sputtering (HiP-IMS), and bipolar HiPIMS, through molecular dynamics simulations. Experimentally determined energy distribution functions were utilized to model the deposition processes. Our results indicate significant differences in the film quality, growth rate, and substrate erosion between the various physical vapor deposition techniques. Bipolar HiPIMS shows the potential for improved film structure under certain conditions, albeit with increased substrate erosion. Bipolar +180 V HiPIMS with 10 the best film properties in terms of crystallinity and atomic stress among the PVD processes investigated.