Interfacial assembly behavior of temperature-controlled surface-activated fat crystals at oil/water interfaces: characterization, interfacial dynamics, and emulsion-stabilizing capabilities

Oil-water interfaces stabilized by whey protein colloidal particles: Evolution of interfacial rheology during subphase exchanges using simulated digestive fluids

Asphaltenes are largely responsible for crude oil interfacial behavior. Due to their complex molecular nature, studying connections between interfacial properties and molecular structure is challenging, and these connections remain unclear. Several groups have reported on the interfacial behavior of asphaltenes, but a unified picture of both interfacial dynamics and thermodynamics is still missing. We seek to establish connections between asphaltene interfacial morphology and interfacial dynamics by combining interfacial dilatational deformation with microscopic structural imaging analysis. Understanding the behavior of natural asphaltene samples is made difficult by the inherent molecular variability. Therefore, we have also studied the behavior of an asphaltene model compound to draw fundamental structure-property relationships. This work contains simultaneous interfacial deformation and microscopy in systems of natural and model asphaltenes at air-water and decane-water interfaces. How the dynamics of natural asphaltenes influences the morphological and thermodynamic state of the air-water and decane-water interfaces is discussed based on the deviations observed between isotropic and anisotropic deformations. Areas where model asphaltenes can help us to understand the behavior of natural asphaltenes are identified such as its high surface pressure activity and aggregation character. An aggregation mechanism for model and natural asphaltenes is proposed based on an observed relationship between microscopic and millimetric aggregates.

Interfacial adsorption dynamics of solid lipid particles at oil/water interfaces through QCM-D technique

Ice cream is a complex multiphase structure consisting of ice, air, and fat as dispersed phases at a range of different length-scales, all embedded in a continuous phase consisting of unfrozen sugar solution known as the matrix or serum. The entire structure is the result of both the ingredients and all the processes used in cream manufacture including emulsification, freezing, and aeration. It is thermodynamically unstable and delivered quality can only be assured at low and stable temperatures. Physicochemical processes during storage can lead to loss of quality by coarsening of the particles, disproportionation of the air, and the loss of water from the matrix. Product design for specific sensory, stability, shape, and increasingly, nutritional properties, is a challenging task and must take account of all these aspects of the structure. Almost all properties are sensitive to the size, density, and morphology of the dispersed phases as droplets, cells, crystals, or even micelles. Finer structures, in general, result in more desirable organoleptic properties such as creaminess and smoothness but the interfacial dynamics are more rapid, leading to less stability. Even small changes in the relative densities of the dispersed phases such as in the case of low-fat or fat-free products can dramatically change key properties such as taste perception, mouth-feel, and rate of melt. Conventional formulation and processing techniques complemented by the use of specific additives such as emulsifiers and stabilizers enable some control, albeit limited, over the interfacial dynamics and stability. New ingredients and new technologies (such as low temperature extrusion) have been developed to enable higher levels of control on the interfacial behavior either through direct molecular intervention on an interface or new structuring processes wherein interfaces are created in a new or different way. Examples of new ways of influencing the ice, fat, and air interfaces will be discussed such as ice structuring protein and hydrophobins. Challenges that remain highlight the need for new types of molecular and microstructural interventions to achieve the next levels in design capability for the creams of tomorrow.

An aqueous hyaluronic acid (HA(aq)) pericellular coat, when mediating the tactile aspect of cellular contact inhibition, has three tasks: interface formation, mechanical signal transmission and interface separation. To quantify the interfacial adhesive behavior of HA(aq), we induce simultaneous interface formation and separation between HA(aq) and a model hydrophobic, hysteretic Si-SAM surface. While surface tension γ remains essentially constant, interface formation and separation depend greatly on concentration (5 ≤ C ≤ 30 mg mL(-1)), molecular weight (6 ≤ MW ≤ 2000 kDa) and interfacial velocity (0 ≤ V ≤ 3 mm s(-1)), each of which affect shear elastic and loss moduli G′ and G′′, respectively. Viscoelasticity dictates the mode of interfacial motion: wetting-dewetting, capillary necking, or rolling. Wetting-dewetting is quantified using advancing and receding contact angles θ(A) and θ(R), and the hysteresis between them, yielding data landscapes for each C above the [MW, V] plane. The landscape sizes, shapes, and curvatures disclose the interplay, between surface tension and viscoelasticity, which governs interfacial dynamics. Gel point coordinates modulus G and angular frequency ω appear to predict wetting-dewetting (G < 75 ω0.2), capillary necking (75 ω0.2 < G < 200 ω0.075) or rolling (G > 200ω0.075). Dominantly dissipative HA(aq) sticks to itself and distorts irreversibly before separating, while dominantly elastic HA(aq) makes contact and separates with only minor, reversible distortion. We propose the dimensionless number (G′V)/(ω(r)γ), varying from 10(-5) to 10(3) in this work, as a tool to predict the mode of interface formation-separation by relating interfacial kinetics with bulk viscoelasticity. Cellular contact inhibition may be thus aided or compromised by physiological or interventional shifts in [C, MW, V], and thus in (G′V)/(ω(r)γ), which affect both mechanotransduction and interfacial dynamics. These observations, understood in terms of physical properties, may be broadened to probe interfacial dynamics of other viscoelastic aqueous biopolymers.

To simulate the interfacial behaviors in real heterogeneous systems, the point contact condition is constructed to study the classical immiscible displacement problem in this work. Specifically, the interfacial dynamics during the water droplet passing through the oil capillary bridge formed under the point contact condition is investigated. Emphasis is put on the influences of the wettabilities and the relative separation motion of the solid surfaces on the dynamic behavior of the droplets. The observations suggested that the capillary pressure had negligible effect on the movement of the water droplet when it was passing though the oil capillary bridge. The wettability and the relative separation of the disk and ball would influence the final adhesion behaviors of the water droplet after the droplet passed through the oil capillary bridge. Surface tension and adhesion energy were used to interpret these observations.

Effect of composition of emulsifier blends on aerated emulsions: Stability, thermodynamic, interfacial behavior and aeration properties

The global demand for high energy density, safe, and long-lasting energy storage systems continues to grow with the rapid advancement of electric vehicles, portable electronics, and renewable energy technologies. Among next-generation battery chemistries, lithium (Li) metal batteries (LMBs), which use Li as the negative electrode, are particularly promising due to the high theoretical capacity (3,860 mAh g−1), low electrochemical potential (−3.04 V vs. SHE), and low gravimetric density (0.534 g/cm3) of Li metal.[1] However, their practical implementation remains limited by safety concerns and poor cycle life, primarily arising from the high reactivity of Li metal, which can lead to dendritic formation and unstable solid electrolyte interphase (SEI).To address these challenges, the development of advanced electrolyte systems is critical. Among these, ionic liquid (IL) electrolytes, typically defined as molten salts with melting points below 100 °C, offer significant advantages including non-volatility, high thermal stability, and wide electrochemical windows, making them attractive alternatives to conventional organic solvent-based electrolytes.[2] However, the complex interfacial chemistry and ion transport behavior of Li⁺ in IL systems remain poorly understood, posing a major barrier to the rational design of high-performance LMBs.Here, we present molecular-level insights into the interfacial dynamics and transport properties of IL electrolytes relevant to Li metal anodes, based on classical and reactive force field (ReaxFF) molecular dynamics (MD) simulations. Our study shows two complementary investigations: (1) the Li-ion transport behavior in bulk IL electrolytes under varying composition and electric field, and (2) the formation and structural characteristics of the SEI at the Li metal-IL interface.We first report Li-ion dynamics in bulk IL electrolytes composed of imidazolium-based cations, 1-ethyl-3-methylimidazolium (EMIM) and 1-butyl-3-methylimidazolium (BMIM), and the bis(trifluoromethylsulfonyl)imide (TFSI) anion, doped with varying concentrations of LiTFSI salt. Our simulations reveal highly heterogeneous Li-ion dynamics, with diffusivities varying by up to two orders of magnitude depending on local microenvironments.[3] Specifically, the degree of Li+ coordination with TFSI anions and the spatial organization of cations dramatically influence transport behavior. The oxygen atoms in the TFSI anion form dynamic solvation cages that govern Li+ hopping and migration pathways, while IL cations modulate these interactions by transiently destabilizing the Li-TFSI coordination. The fast Li-ion diffusion occurs via the hopping mechanism, with Li-ions jumping from one cage to another, while the Li-ion diffusion via the vehicular mechanism is slow. The ion diffusion is affected only slightly under E-fields less than 0.05V/Å, indicating the dominance of local solvation dynamics over field-driven effects in these systems.We also investigate interfacial reactivity and SEI formation using ReaxFF simulations with [BMIM][TFSI] in contact with a Li metal anode.[4] Upon interfacial contact, the IL components decompose spontaneously, with distinct decomposition pathways and rates for the cations and anions. This leads to the formation of a bilayered SEI structure, approximately 10 nm thick, comprising a dense, inorganic-rich layer adjacent to the Li metal and a more porous, organic-rich layer toward the electrolyte. This layered morphology is expected to significantly influence both charge transfer kinetics and ion transport. The observed spatial and chemical heterogeneity within the SEI suggests the presence of multiple, coexisting charge transfer pathways and localized interfacial environments.Taken together, our work provides a comprehensive molecular-level framework for understanding both bulk ion transport and interfacial phenomena in IL-based electrolytes for LMBs. By revealing the complex relationship between local solvation environments, Li-ion diffusion mechanisms, and SEI structural evolution, we highlight the role of ionic liquid components in governing electrochemical performance. These insights not only deepen our fundamental understanding of charge transfer and ion transport processes in reactive metal–IL systems but also point to design strategies for optimizing electrolyte formulations to enhance interfacial stability, ion mobility, and overall battery performance. Our findings contribute to the broader goal of developing highly efficient LMBs through rational, simulation-guided electrolyte design.Acknowledgements:We acknowledge the support from LG Chem. and Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government.

Multitudinous studies have been carried out on the controllable functionalization and performance evaluation of graphene oxide (GO). In this study, the correlation between the amount of grafted alkylamine on GO and its interfacial assembly behavior at liquid-liquid and liquid-solid interfaces was studied. GO was modified with n-octylamine through basal functionalization (bGO). The grafting amount of alkylamines was regulated using two GOs varied in oxidation degree (GO_L and GO_H). A study on the oil-water interfacial behaviors shows that bGO_L has better ability to modulate the interfacial tension than that of bGO_H. Grafting alkylamine on GO will not only increase the interaction strength with oil while weaken that with water but also do damage to the graphene lattice and weaken the interaction of π-π stacking; therefore, bGO_L displays a broader capability to modulate interfacial tensions than that of bGO_H. The bGO-based Pickering emulsion was prepared, and the interfacial behavior at the liquid-solid interface was investigated. A study on the interfacial anti-rust performances demonstrates that grafted alkyl chains in bGOs can form more compact and ordered protective films on the metal surface and enhance the hydrophobicity as a result of the similar structure to oil in the emulsion system, which makes Pickering emulsions show better anti-rust abilities than water dispersions. Meanwhile, the bGO_H emulsion shows a better anti-rust property than that of the bGO_L emulsion. A study on the interfacial tribological behaviors shows that the lubricity of bGO_L is better than that of bGO_H. X-ray photoelectron spectroscopy analysis shows that a high content of C-O-C/C-OH in lubricating films contributes to the improvement of lubricity. The modulated interfacial assembly properties of GO at both liquid-liquid and solid-liquid interfaces suggest their potential applications in surface protection, lubrication, controllable drug deliveries, absorption and separation, nanocomposites, and catalyst fields.

Interfacial assembly and properties of amphiphilic polymer-grafted nanoparticles: Effect of chemical design and density of grafted polymers

Application of the lattice Boltzmann method to two-phase Rayleigh–Benard convection with a deformable interface

Lattice Boltzmann methods for single-phase and solid-liquid phase-change heat transfer in porous media: A review

This study investigates the impact of aluminum trihydrate (ATH) and triphenyl phosphate (TPP) on the flame retardancy and adhesive properties of thermoplastic polyurethane (TPU), focusing on their dispersion behavior and surface interactions within the polymer. Scanning electron microscopy revealed distinct dispersion characteristics of ATH and TPP, influencing the formation of interfacial structures that enhance flame retardancy. Differential scanning calorimetry analysis was used to examine the thermal behavior of the adhesive sheets. The results indicate that TPP facilitates the formation of a protective char layer at the material surface, thereby improving thermal resistance and inhibiting flame propagation. In contrast, ATH primarily relies on endothermic and water vapor release, exhibiting a less stable interface with the TPU. These results highlight the crucial role of surface morphology and interfacial dynamics in enhancing the flame resistance and adhesive properties of TPU, contributing to a deeper understanding of surface and interface behavior.

Sodium–air (Na–air) batteries have emerged as promising candidates for next-generation energy storage systems due to their high theoretical energy density, the natural abundance of sodium, and their cost-effectiveness compared to lithium-based counterparts. In a Na–air battery, atmospheric oxygen acts as the cathodic reactant, eliminating the need for heavy and expensive cathode materials, and thus reducing the overall system cost. However, the practical realization of Na–air batteries faces several critical challenges, particularly those associated with complex electrochemical reactions at the air–electrolyte–electrode interface, sluggish ionic transport, and poor interfacial stability. Addressing these issues requires a fundamental understanding of the atomic-scale mechanisms and material properties that govern ion conductivity, redox kinetics, and phase stability under realistic operating conditions.In this study, we present a comprehensive multi-scale modeling framework that integrates density functional theory (DFT), ab-initio molecular dynamics (AIMD), and machine learning molecular dynamics (MLMD) to investigate the electrochemical interfacial properties of Na–air batteries(Figure a and b). We began by performing DFT-based structural optimizations of key sodium compounds involved in battery reactions, including metallic sodium (Na), sodium oxide (Na2O), sodium peroxide (Na2O2), and cubic sodium superoxide (NaO2). These optimizations were carried out using the Vienna Ab-initio Simulation Package (VASP). The optimized lattice parameters for the structures (Figure-a) were: Na (a = b = 3.68 Å, c = 6.26 Å, α = β = 90°, γ = 120°), Na2O (a = b = c = 5.48 Å, cubic), Na2O2 (a = b = 6.13 Å, c = 4.42 Å, γ = 120°), and NaO2 (cubic, a = b = c = 5.52 Å). The projector augmented wave (PAW) method was used to describe the valence electrons, and the generalized gradient approximation of the Perdew and Wang functional was employed for exchange-correlation effects. A kinetic energy cutoff of 450 eV ensured accurate plane-wave expansion, and the Brillouin zones were sampled using 10×10×10, 12×12×8, and 12×12×10 Monkhorst–Pack k-point meshes for Na2O, Na2O2, and NaO2, respectively. Structural optimization proceeded until ionic forces were minimized below ±10 meV/Å.To explore the mechanisms of sodium and oxygen diffusion at interfaces such as Na2O|Na2O2 and Na2O2|NaO2, we designed crystalline interfaces and performed AIMD simulations at 1000 K. These simulations generated amorphous phases and captured realistic atomic disorder under operating conditions. The AIMD simulations were run in the NVT ensemble for up to 100 ps using a 1 fs timestep.Using the optimized crystalline structures, we calculated migration barriers for Na⁺ ions, atomic oxygen (O), and molecular oxygen (O₂). These calculations provided critical insights into species-specific transport limitations within the lattice frameworks of the involved compounds. Next, we extended our analysis by using AIMD to sample configurations from both crystalline and amorphous phases. These simulations generated a diverse dataset encompassing thermal fluctuations and disorder representative of battery interfaces. We then trained machine learning force fields (MLFFs) using deep neural network-based models on this dataset. These MLFFs retained near-DFT accuracy while dramatically improving the efficiency and scalability of simulations. With these trained MLFFs, we conducted large-scale MLMD simulations of the electrochemical interface in Na–air batteries, considering both crystalline and amorphous environments. The simulations enabled access to larger supercells (>10,000 atoms) and longer timescales (nanoseconds), offering statistically robust insights into rare but crucial events such as defect migration and phase transitions.From the MLMD simulations, we calculated transport properties including mean squared displacement (MSD), diffusion coefficients, ionic conductivity, and activation energies across a range of temperatures. Our results revealed that amorphous phases generally exhibit enhanced ionic mobility due to increased structural disorder and flexibility. Additionally, we investigated interfacial stability and sodium migration mechanisms across crystal–crystal and crystal–amorphous boundaries, uncovering vital differences in transport dynamics and energy barriers.In conclusion, this study delivers an in-depth, atomic-scale analysis of the materials and interfacial behavior in Na–air batteries. A significant outcome of this work is the demonstration of MLMD as a powerful alternative to traditional AIMD. By combining DFT, AIMD, and MLMD techniques, we provide a predictive and mechanistic understanding of ionic transport, phase behavior, and interfacial dynamics. The methodologies and insights from this work pave the way for the rational design of next-generation high-performance Na–air batteries. Figure 1

Efficient fluid displacement during primary cementing is critical for well integrity and zonal isolation. This study investigates multiphase flow dynamics in annular and tubular geometries, with a focus on density and viscosity ratios, flow regimes, and eccentricity. Large-scale experiments were conducted complemented by 3D numerical simulations. The goal is to assess displacement efficiency, quantify residual films associated to eventual stagnant regions, and analyze fluid interface behavior under field-representative conditions. Experiments were conducted in a custom 14.4 m vertical test unit, equipped with pressure, density, and flow rate sensors. Tests included upward/downward flows and concentric/eccentric setups using Newtonian and non-Newtonian fluids under laminar and turbulent conditions. Density and viscosity ratios were varied to evaluate their effects on displacement. Displacement efficiency was determined with pumped volume and residual fluid measurements. Parallel CFD simulations in OpenFOAM replicated experimental conditions, using mesh refinement, k–ω SST turbulence modeling, and convergence checks. CFD outputs pressure drop, volumetric fractions, and interface dynamics—were validated against experimental results to confirm the accuracy and robustness of the model. Experimental and CFD results demonstrated strong agreement across variety of flow conditions. In upward flows, a displacing-to-displaced fluid density ratio greater than one consistently led to near-complete displacement, while lower density ratios (Rd &amp;lt; 1) introduced flow instabilities and reduced displacement efficiency. Discrepancies between internal volume fractions and outlet compositions suggest the presence of displacing fluid fingering. Turbulent flow mitigated the negative effects of low Rd and eccentricity, improving efficiency compared to laminar flow. Viscosity ratio exhibited a secondary effect: higher viscosity ratios helped stabilize the two-fluid interface and improved efficiency when Rd &amp;gt; 1. Eccentricity significantly influenced displacement in laminar flow, especially with Rd &amp;lt; 1, though differences between intermediate (0.17) and severe (0.6) eccentricities were minor. Emulsion formation from specific fluid formulations increased residual displaced volumes in some cases. Residual films and partial mixing were quantified, and CFD accurately captured these behaviors. These findings highlight the importance of designing fluids with favorable density and viscosity ratios, operating in turbulent regimes when possible, and minimizing eccentricity or compensating for it through fluid properties. CFD proved effective in predicting complex flow dynamics, supporting its use in planning and optimizing cementing operations under realistic well conditions. This work presents a unique large-scale experimental dataset with hydrodynamic similarity, including annular and tubular tests using Newtonian, non-Newtonian, and synthetic fluids. Though not used in simulations, synthetic fluids enabled controlled evaluation of interface behavior and residual films. Validated 3D CFD simulations captured effects of non-Newtonian rheology, eccentricity, and density ratio, extending experimental results to real applications where aspect ratios are different. These approaches enhance modeling and support realistic optimization of primary cementing and well-cleaning.