The Temperature Adjustable Membrane Emulsification Device (TAMED) was developed and evaluated as an automated and temperature-controlled system for laboratory-scale membrane emulsification. The device replaces repeated manual syringe extrusion with an automated sequence in which two pneumatic piston pumps alternately force the batch volume through a syringe filter. Oil-in-water emulsions containing 3.5 vol.% or 30 vol.% medium chain triglyceride oil and stabilized with polysorbate 20 or polysorbate 80 were processed at 23 °C and 60 °C. 15 mL emulsion batches with uniform droplet sizes were produced by adding the oil and aqueous phases directly to the same syringe without prior premixing, and applying 20 passes through a composite membrane with a nominal pore size of 10 μm.Increasing the number of passes progressively reduced the Sauter mean diameter and narrowed the droplet size distribution (span ≈ 1). After 20 passes, Sauter mean diameters of approximately 2.0–2.9 μm were obtained. Similar final droplet size distributions were observed with and without prior mixing. Both surfactants produced significantly smaller droplets at 60 °C than at 23 °C. Importantly, this decrease occurred despite a lower transmembrane flux at 60 °C, indicating that the reduction in interfacial tension outweighed the opposing effects of the lower continuous-phase viscosity and transmembrane flux. Surfactant type and dispersed phase content also significantly affected the final droplet size. In addition, direction-dependent differences were observed in membrane resistance and transmembrane flux.Within the investigated process and formulation range, TAMED enabled automated in-situ preparation and repeated extrusion of small emulsion volumes under defined temperature and cycle conditions. The device therefore provides a laboratory-scale platform for investigating the effects of process and formulation parameters on membrane emulsification.
The growing threat of multidrug-resistant (MDR) pathogens drives interest in multifunctional nanomaterials that combine antimicrobial efficacy with inflammation control. Herein, a novel one-step, light-driven synthesis of curcumin-capped selenium nanoparticles (CurSeNPs) stabilized with PEG is reported. The influence of synthesis irradiation time (1–4 min) on the photochemical and photophysical properties was investigated. The resulting spherical nanoparticles contain covalently incorporated bioactive curcumin within the PEG network via photoreduction. Photophysical characterization demonstrated a pronounced aggregation-induced emission (AIE) effect. While CurSe 1 min showed the highest singlet oxygen (1O2) yield (5.24-fold enhancement), CurSe 3 min exhibited the longest fluorescence lifetime (1.01 ns) and moderate 1O2 (2.71-fold enhancement). CurSe 3 min was selected as optimal due to its superior balance of colloidal stability (∼-34 mV), fluorescence, and photodynamic activity. Antimicrobial assays revealed broad-spectrum dark activity against Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, and Candida albicans. Notably, blue-light irradiation (460 nm, 15 min, ∼27 J/cm2) enabled CurSe 3 min to achieve a 2.54 log reduction against MDR A. baumannii (vs. 0.92 log for free curcumin; p < 0.01), where the 1O2 enhancement closely correlated with a 2.76-fold antimicrobial improvement. In RAW 264.7 cells, CurSeNPs induced dose-dependent cytotoxicity and suppressed NO production in the dark. These dark effects were not reversed by catalase or thiourea, indicating ROS-independent mechanisms, such as direct nanoparticle–cell interactions. In conclusion, green-synthesized CurSeNPs represent a promising multifunctional nanoplatform that combines enhanced photophysical properties, broad-spectrum antimicrobial activity, and anti-inflammatory effects, positioning them as versatile candidates for wound infection management.
In aqueous colloids, various entities can carry charges such as nanoparticles dispersed in electrolyte medium or polyelectrolytes (ionic macromolecules) dissolved in water. A local electrostatic field is created, which counteracts further charge separation. pH-dependent charges can form in protonation/deprotonation equilibria, which can be quantified by potentiometric acid-base titration. We have developed a general adsorption model to evaluate such titrations. After calibrating the system for both pH and concentration, the difference between the added and equilibrium concentration of H+/OH− ions corresponds to the protonation/deprotonation reactions that generate the charges on colloids. Both the amount and the sign of charge can be derived directly from this difference using the proton material balance equation. The pH- and ionic strength dependent degree of dissociation of polyelectrolytes can also be calculated directly. The experimental data can be successfully fitted using surface complexation models (SCMs). In this work, we present experimental and fitting results of acid base titrations for polyacrylic acids of different molecular weights (1.8, 5, 90 and 700 kDa) and poly(acrylic acid-co-maleic acid) 3 kDa comparing them with each other and with the acrylic acid monomer. This work revealed that pKa values from fitting constant capacitance and diffuse layer models showed a nearly linear dependence on ionic strength and varied significantly with molecular size. The larger the molecules, the weaker the acidity of the same acidic group (COOH) at low ionic strengths, which decreases with increasing ionic strength, while at ∼0.5 M concentration the difference disappears.
The London dispersive component of surface energy (γsd) is a fundamental interfacial parameter governing van der Waals interactions between solid materials and surrounding molecules. Its accurate determination is essential for understanding and controlling a wide range of processes, including adhesion, wetting, catalysis, tribology, pharmaceutical formulation, nanomedicine, as well as energy and environmental technologies. Despite decades of investigation, the reliable determination of γsd for solid materials remains a major challenge. Conventional approaches, such as contact angle measurements and calorimetric methods, are generally limited to well-defined planar surfaces or specific material systems. In contrast, inverse gas chromatography (IGC) has emerged as a powerful and versatile technique for characterizing powders, fibers, and porous solids.In this work, a rigorous thermodynamic framework is developed based on the Hamaker constant, enabling the intrinsic determination of the dispersive surface energy γsd(T) of oxide materials. A key advance lies in the explicit incorporation of the temperature-dependent intermolecular separation distance D0(T), extracted from inverse gas chromatography measurements of n-alkane adsorption.Application to a series of oxides (Al2O3, SiO2, ZnO, TiO2, and MgO) reveals a consistent hierarchy of dispersive surface energies, governed primarily by electronic polarizability and surface dielectric screening. While the Hamaker constant exhibits only weak temperature dependence, the observed variation of γsd(T) is shown to arise predominantly from changes in interfacial configuration through D0(T). This demonstrates that thermal effects on dispersive interactions are controlled by structural fluctuations rather than intrinsic electronic properties.The proposed methodology provides a unified description linking microscopic interaction distances to macroscopic surface energetics. It establishes a robust and physically grounded approach for determining dispersive surface energies and offers new insight into the fundamental mechanisms governing adhesion and interfacial interactions in solid materials.
Photocatalytic water splitting driven by solar energy offers a sustainable route for hydrogen production as a clean, carbon-free energy carrier. Among the semiconductor photocatalysts investigated, zinc oxide (ZnO) and titanium dioxide (TiO2) have attracted significant attention due to their chemical stability, low toxicity, favorable band-edge positions, and cost-effectiveness. However, their wide band gaps limit light absorption mainly to the ultraviolet region, leading to suboptimal utilization of the solar spectrum and rapid recombination of photogenerated charge carriers. To address these limitations, this mini-review focuses on the rational design and analysis of ZnO–TiO2-based heterojunction photocatalysts aimed at enhancing charge separation and extending visible-light absorption. Particular emphasis is placed on interfacial interactions and charge transfer pathways in ZnO–TiO2 heterojunctions that govern solar-driven hydrogen evolution. Recent advances in nanocomposite structures are critically discussed, along with key challenges related to photocatalytic performance, operational stability, and scalability, providing insights for the development of efficient, practical, and sustainable oxide-based photocatalysts.
To address the challenges of microbiologically influenced corrosion on Q355 steel in marine environments and the bottleneck in regulating the protection efficiency of Cathodic Protection (CP) with sacrificial anodes, this study constructed a CP system using Al-Zn-In-Cd sacrificial anodes in natural seawater. This study investigated the influence mechanisms by which different cathode-to-anode exposed area ratios (1:1, 40:1, 80:1) affect the corrosion behavior, evolution of corrosion product layers, and the succession of microbial communities of Q355 steel, with a specific focus on revealing the mechanisms of early biomineralization and community succession. The unprotected Q355 steel exhibited a corrosion rate of 246.43 μm/y, with a loose rust layer dominated by β-FeOOH and green rust formed on its surface. The microbial community of the unprotected steel exhibited high diversity, with 111 unique Operational Taxonomic Units (OTUs) identified, and was enriched with iron-oxidizing bacteria such as Mariprofundus. After applying CP, the corrosion rate decreased significantly. In the CP-treated Q355 system with a cathode-to-anode area ratio of 1:1, the corrosion rate decreased to 1.93 μm/y corresponding to a protection efficiency of up to 99.21%. The microbial community structure was distinctly different from that of the unprotected Q355 system and other CP systems, with Thiomicrohabdus accounting for 90.53%. As the area ratio increased to 40:1 and 80:1, the protection efficiency decreased sequentially to 62.98% and 43.00%, respectively. Notably, the CP Q355-80 system with an area ratio of 80:1 had a maximum pitting depth of 36.51 μm.
Carbon quantum dots (CQDs) have emerged as a promising class of nanocarbons owing to their ultrasmall dimensions and highly tunable surface properties. In this study, high-performance amphiphilic sucrose-based carbon quantum dots (s-CQDs) were successfully synthesized via a facile, one-step solvothermal method tailored for enhanced oil recovery (EOR) applications. The s-CQDs were prepared by reacting sucrose with dodecylamine at a 1:1 M ratio at 180 °C for 3 h. Comprehensive characterization (TEM, FT-IR, and XPS) confirmed the formation of monodisperse, quasi-spherical nanoparticles with an average core diameter of ∼4.1 nm, effectively functionalized with hydrophilic hydroxyl and amino groups alongside hydrophobic alkyl chains. The as-prepared s-CQDs exhibited robust thermal stability up to 180 °C, and their aqueous dispersions maintained excellent colloidal stability at temperatures up to 90 °C and in highly saline environments containing up to 7000 mg L−1 of NaCl or CaCl2. At a target concentration of 0.3 wt%, the s-CQDs reduced the surface tension of water to 29 mN m−1 and lowered the interfacial tension (IFT) between n-decane and deionized water to 4.3 mN m−1, demonstrating pronounced interfacial activity. Stable n-decane/water emulsions were achieved at s-CQD concentrations exceeding 0.4 wt%, displaying outstanding long-term resistance to coalescence. Furthermore, the s-CQDs significantly altered the wettability of model oil-wet surfaces, successfully reversing the water contact angle from an initial 88.0° to a more water-wet 55.6°. Given their straightforward preparation, cost-effectiveness, and superior interfacial performance, these amphiphilic s-CQDs hold strong potential as an efficient and scalable nanofluid system for chemical EOR.
Complexes of cyanidin 3-O-glucoside (CND) and alginate (Alg) form long-range supramolecular structures at pH 4, where CND is predominantly uncharged. Under these conditions, the complexes exhibit pronounced chiroptical activity, with Circular Dichroism (CD) bands significantly more intense than those of free CND or of CND/Alg complexes formed at lower pH values. Alginate consists of guluronic and mannuronic acid units, which differ in the axial or equatorial orientation of one carboxyl group, respectively. To gain insight into the molecular basis of CND–alginate complexation, CND was separately complexed with polyguluronic (PolyG) and polymannuronic (PolyM) acids. In both cases, only small aggregates were formed, with sizes around 200 nm as measured by Dynamic Light Scattering (DLS) and 60–120 nm by Atomic Force Microscopy (AFM) in the dry state. These aggregates lacked the characteristic CD bands observed for CND/Alg complexes at pH 4. Molecular dynamics simulations showed that the spacing between successive carboxylate groups interacting with CND molecules in PolyG and PolyM acids is approximately 7.5–8.0 Å. In alginate, however, an additional shorter distance of about 5.0 Å is present, arising from the alternating guluronic and mannuronic residues along the polymer chain. These results suggest that the alternation of guluronic and mannuronic units in alginate plays an important role in promoting CND–CND interactions, driving cooperative assembly and the formation of extended supramolecular structures with enhanced chiroptical response.
Production of oil is associated with large volumes of produced water that are co-produced as a byproduct. In most cases it is either used for re-injection or discharged to the sea in offshore production. Operation of the oil production site and the quality of oil and water require certain production chemicals to be added in different doses. These chemicals can affect the quality of the discharged water in terms of oil-in-water as they interfere with the oil droplet removal processes based on droplet size and coalescence. The ability to suppress coalescence is a complex function of the chemistry of both oil and water phases. To understand the contribution from the water phase alone without the presence of chemistries residing in the oil phase, microfluidic-generated toluene droplets are examined in five different produced water samples taken at the discharge point after completed treatment. The tendency of toluene droplets to coalesce is quantified by the coalescence frequency using high-speed camera video acquisition. We find large variations in the ability of the produced water samples to stabilize oil droplets. Compared to Milli-Q water as the continuous phase, the coalescence frequency is reduced from 84 to 1 mean coalescence event per time unit. The visual data is assisted by analytical data from capillary electrophoresis where the ionic composition of the water samples is quantified. A commercial corrosion inhibitor that is known to be used upstream in production at four of the fields is also identified and quantified using capillary electrophoresis. It is measured to be present in all produced water samples except sample E with no apparent impact alone on the coalescence frequency of the toluene droplets. Furthermore, no quantitative correlation was found between other measured properties of the water samples and the coalescence frequency, although the data provided potential explanations of e.g. differences in oil-in-water content.
The electric-field deformation of polymer droplets, broadly known as electrohydrodynamics (EHD), offers significant advantages for fabricating micro-optical components, such as adaptive lenses and custom optical surfaces, due to their smooth surfaces and ability to form freeform surfaces. When utilizing UV-curable polymers, these droplets can be cured in an electrically deformed state, yielding solid freeform microlenses. A critical requirement for these technologies is the ability to accurately model the final droplet shape, as the interface curvature directly determines the optical performance of the resulting optical component. This paper introduces a novel framework for resolving the electric-field deformation of polymer droplets through pressure-curvature analysis, extending the foundational Young-Laplace equation to incorporate hydrostatic and Maxwell pressures derived from 2D Finite Element Method (FEM) simulations. A critical component of this methodology is the explicit inclusion of an optimized effective surface charge sigma s, which is crucial for achieving high prediction accuracy in leaky dielectrics. Our analysis demonstrates that accounting for these charges, originating from the Maxwell-Wagner effect, reduces the shape prediction error by up to a factor of two. Validated through experiments using the UV-curable polymer PR48 and oleic acid across various electrode configurations and applied voltages, the model achieves a low average Root Mean Square Error (RMSE) in the range of 10-50 mu m for the final droplet contour. The effective surface charge exhibits a predictable, linear dependence on applied voltage for leaky dielectrics. This computationally efficient 2D approach offers rapid estimation for micro-optical component fabrication.
The micellization behavior of urea-based cationic gemini surfactants was investigated using small-angle neutron scattering (SANS) with multi-model form factor analysis. A homologous series of surfactants with urea group included in the hydrophobic tail and polymethylene spacers consisting of two to ten methylene units was analyzed using three form factor models: a core–shell ellipsoid and two variants of homogeneous ellipsoids. The results from all models show a consistent trend of the micelle structures, confirming that the spacer length critically influences micellar geometry, aggregation number, and hydration. The surfactant with four CH2 groups in the spacer formed the largest micelles with the highest aggregation number, while longer spacers led to progressively smaller, more compact aggregates. The shell hydration—quantified as the volume fraction of heavy water within the hydrophilic region—decreased systematically with increasing spacer length due to enhanced hydrophobicity of the headgroup-spacer region. Intermicellar interactions, modeled as screened Coulomb interaction using the rescaled mean spherical approximation (RMSA), revealed the strongest electrostatic repulsion for the case of four methylene groups in the spacer, corresponding to the highest micellar charge and largest interparticle spacing. The observed spacer-dependent trends were robust across all modeling approaches, demonstrating that the spacer length serves as a key structural determinant of self-assembly in this type of urea-based gemini systems. These findings provide insight into the design of gemini surfactants with tailored aggregation behavior for applications in drug delivery, nanostructure templating, and solubilization technologies.
Titanium dioxide (TiO2) is a widely used photocatalyst, although its performance can be improved by modification with carbon-based nanomaterials. In this study, carbon dots (CDs) derived from tamarind seeds (Tamarindus indica L.) were used to prepare a TiO2/CDs nanocomposite via a hydrothermal method for the photodegradation of naphthol green B (NGB) dye in aqueous solution. The synthesized materials were characterized using XRD, HR-TEM, SEM, FTIR, UV-Vis, PL, XPS, and BET. The CDs exhibited blue luminescence under UV light, and the average particle size was 7.14 nm. The absorption wavelength of pure TiO2 was 354 nm, the band gap energy was 3.74 eV, and the average particle size was 203.64 nm, whereas the absorption peak of the TiO2/CDs nanocomposite was 347 nm, the band gap energy was 3.61 eV, and the average particle size was 147.67 nm. Photocatalytic degradation of NGB was evaluated under UV irradiation, and the TiO2/CDs nanocomposite showed the highest degradation efficiency, reaching 99.98% after 120 min. These findings indicate that tamarind-seed-derived CDs can serve as a promising biomass-based modifier for TiO2 in NGB photodegradation under the experimental conditions used in this study.
Epilepsy, a chronic neurological disorder marked by recurrent seizures, remains a major global health concern due to limitations in current therapeutic strategies. Conventional antiepileptic drugs (AEDs) such as phenytoin, valproate, lamotrigine, and levetiracetam often exhibit poor solubility, low bioavailability, extensive hepatic metabolism, and restricted permeability across the blood–brain barrier (BBB). These pharmacokinetic and physiological barriers contribute to delayed onset of action, systemic toxicity, and subtherapeutic brain concentrations—particularly problematic in status epilepticus and drug-resistant epilepsy (DRE), which affects nearly 30–40% of patients. Nanotechnology-based delivery platforms have emerged as transformative approaches to overcome these limitations. Systems such as nanoemulsions, microemulsions, nanostructured lipid carriers (NLCs), polymeric micelles, PLGA nanoparticles (PLGA-NPs), and chitosan-based nanoparticles offer enhanced solubility, controlled release, and improved BBB penetration. Among these, intranasal drug delivery—especially via nasal sprays—has gained prominence for its ability to bypass the BBB through olfactory and trigeminal pathways, enabling rapid and targeted brain delivery while minimizing systemic side effects. These nanocarrier-based intranasal systems demonstrate superior pharmacokinetic performance, improved bioavailability, and reduced dosing frequency, offering a patient-friendly alternative for epilepsy management. This review comprehensively discusses recent advancements in nanoparticle-mediated intranasal drug delivery for epilepsy, highlighting formulation strategies, mechanisms of brain targeting, and translational potential. Overall, the integration of nanocarrier-based intranasal delivery systems into clinical practice holds significant promise for improving therapeutic efficacy, patient compliance, and personalized management of refractory epilepsy in future clinical settings.
Determination of the physical state of a polymer, whether it is undissolved (solid), as in the case of a microplastic, swollen or fully dissolved, is essential when considering the properties and behaviour of polymeric formulations, but remains challenging within the complex formulations found in many fast moving consumer goods (FMCG). This information is also critical when considering the regulatory controls associated with the application of polymeric formulations. It is, therefore, important to be able to determine and quantify the presence and relative proportion of undissolved polymers within a formulation. Such quantification needs to be simple, rapid and robust for regulatory purposes, but has proved challenging to implement in complex formulations. In this paper, we address this challenge by introducing a novel measure of the degree of solid and undissolved polymer, based on time domain (TD) nuclear magnetic resonance (NMR). Using 1H solid-echo (SE) Carr-Purcell-Meiboom-Gill (CPMG) transverse NMR relaxation curves, we calculate a restricted mobility index, which provides a measure of the proportion of immobile hydrogen atoms present in a sample, arising from solid and undissolved polymeric components within the formulation. Restricted mobility indices are determined for polyvinyl pyrrolidone (PVP), polyquaternium-37 and cellulose polymer formulations as a function or temperature, pH, concentration and processing regime. This method is rapid, easy to implement and does not suffer from the same level of subjectivity as multicomponent fitting or inverse Laplace transforms. The robustness and repeatability of this method is demonstrated across a variety of different TD NMR instruments.
Hydrophobic deep eutectic solvents (DESs) have recently emerged as sustainable and versatile liquid media, yet their fundamental behavior as colloidal dispersants remains poorly understood. Here, we examine a natural hydrophobic DES composed of thymol and coumarin as a medium for dispersing TiO2 nanoparticles. Spectroscopic analyses confirm the formation of a hydrogen-bonded eutectic structure and reveal favorable adsorption of DES molecules onto TiO2 surfaces. Time-domain nuclear magnetic resonance (NMR) measurements further show that this DES provides markedly stronger solvation of TiO2 compared with conventional hydrophobic liquids. Although the resulting suspensions possess limited intrinsic stability, we demonstrate that the introduction of a minute amount of water—immiscible with the DES yet strongly wetting toward TiO2—significantly enhances the rheological rigidity of the suspensions, likely through water-mediated capillary bridging, thereby effectively suppressing sedimentation-driven phase separation. Beyond stability control, the DES-based suspensions exhibit exceptional UV-shielding performance. The neat DES shows inherent UV absorbance, and the incorporation of TiO2 elevates the sun protection factor (SPF) to values exceeding 100, outperforming comparable aqueous and oil-based systems. The addition of water improves coating uniformity while maintaining high SPF performance. These findings establish hydrophobic DESs as a promising platform for designing environmentally benign colloidal formulations with tunable mechanical and optical functionalities.
Adhesive-free bonding of identical polymer materials remains a key challenge in developing recyclable monomaterial plastics. Poly(ethylene terephthalate) (PET), despite its widespread use and established recycling infrastructure, is typically joined using adhesives or welding processes that compromise recyclability or impose thermal and geometric constraints. Here, we report a simple and robust strategy for strong, durable adhesive-free PET–PET bonding based on interfacial chemical interactions, reproducibly achieving uniform bonding even in a solid–solid configuration. Glycol-modified PET (PETG) substrates were activated by low-pressure plasma to introduce oxygen-containing functional groups, including carboxyl groups, and poly(allylamine) (PAA) was introduced at the interface as a molecular crosslinker. After contacting the PAA-treated and plasma-treated substrates with a small amount of water and applying mild thermal treatment below the heat distortion temperature, strong interfacial bonding was achieved without coupling reagents or bulk adhesives. Lap-shear strengths exceeding 10 MPa were obtained, often causing fracture of the PETG substrates rather than interfacial failure. Reliable bonding was achieved over a small area (0.2 × 0.5 cm2) with good reproducibility. The bonded interfaces showed excellent durability, maintaining high strength after one year at room temperature and after immersion in aqueous sodium dodecyl sulfate solution. Spectroscopic and microscopic analyses suggest that a small fraction of interfacial amide bonds forms, contributing to mechanical robustness and chemical durability, while the interfacial layer remains ultrathin and distinct from bulk adhesive layers. This minimalistic, reagent-free process provides a practical pathway toward recyclable monomaterial PET assemblies and provides a practical framework for extending interfacial covalent bonding strategies to other polymer systems.
Bioactive compounds are molecules that play an important role in health; however, their susceptibility to degradation due to factors such as the processing, storage, and gastrointestinal transit has driven the development of delivery and release systems. In this context, protein-based emulgels emerge as attractive matrices that combine the three-dimensional network structure of a gel, which provides mechanical and physical stability, with the properties of an emulsion, which allows for effective encapsulation. The use of proteins in the generation of emulgels is interesting due to their low toxicity and functional properties as emulsifying and gelling agents. This review highlights the role of proteins in the formation of emulgels, their generation process, the impact of their structure and rheological parameters on the bioaccessibility and release kinetics of bioactive compounds. Finally, the application of emulgels in the food industry is detailed, including the areas of functional foods, low-fat foods, and 3D printing.
The present study investigates entropy generation analysis for nonlinear mixed convection TiO2-H2O nanofluid flow over a moving vertical plate with spatially varying heat sources/sinks, slip effects, and viscous dissipation. The obtained set of nonlinear ordinary differential equations from governing equations is solved by applying the MATLAB bvp4c technique, and the accuracy of the computational scheme is validated against benchmark results available in the literature. The findings reveal that TiO2 nanoparticle loading enhances thermal conductivity and heat transport rate, leading to higher fluid temperatures and thicker thermal boundary layers, while simultaneously intensifying entropy generation away from the wall due to viscous effects. Mixed convection exhibits distinct behaviours in assisting and opposing flow regimes; assisting flow reduces entropy generation near the wall due to enhanced convective transport, whereas opposing flow amplifies irreversibility. Nonlinear buoyancy produces crossover effects in entropy distributions and Bejan number profiles, indicating a shift in dominant irreversibility mechanisms across the boundary layer. Velocity slip reduces only entropy generation by weakening near-wall shear stress and viscous dissipation, whereas thermal jump simultaneously decreases both entropy generation and Bejan number by limiting wall-to-fluid heat transfer. The velocity slip and thermal jump can act as key parameters that redistribute and modulate the dominant sources of irreversibility within the flow domain. Spatially varying and thermally varying heat sources elevate temperature and entropy in the far field while reducing near-wall irreversibility, whereas heat sinks produce the opposite effect. Furthermore, an increase in the Brinkman number enhances entropy generation and shifts the dominance toward heat transfer irreversibility, as reflected by a reduction in the Bejan number. Surface drag and heat transfer rate are found to be strongly affected by mixed convection nanoparticle loading, slip conditions, Eckert number, and non-uniform heating. The nanoparticle addition enhances heat transfer at the expense of increased drag, velocity slip reduces skin friction with a moderate impact on thermal performance. Overall, the findings highlight the critical interplay between nonlinear buoyancy, interfacial slip, viscous heating, and non-uniform thermal conditions in controlling entropy generation and provides useful insights for optimizing advanced thermal systems.
The stabilization of Pickering emulsions by nanoclays and water-soluble polymers presents a promising strategy for altering emulsion structure and rheology. In this study, the influence of poly(ethylene oxide) (PEO) with a molecular weight of approximately 100 kg mol-1 on the rheology of oil-in-water emulsions stabilized by the model synthetic nanoclay laponite (R) was systematically investigated. The addition of PEO, which is known to adsorb onto laponite (R) particle surfaces, resulted in significant modifications to the microstructure and rheological properties of the emulsions. Flow curves and oscillatory sweeps were analyzed over a specific period to investigate the viscoelastic properties of the Pickering emulsions. The results reveal that PEO at concentrations greater than or similar to 1 wt% significantly enhances yield stress and viscosity. The flow curves were well-fit by the Herschel-Bulkley model, indicating that the emulsions behaved as a soft viscoelastic solid. We expect this is due to the formation of a polymer network within the continuous phase. As the polymer concentration increases, the zeta potential of laponite (R) decreases, suggesting a reduction in the overall surface charge of laponite (R) particles with polymer adsorption, which may alter particle interactions and emulsion stability. This charge screening effect results in a strong relationship between the polymer concentration and the properties of the emulsion. Microscopic analysis revealed a decrease in average droplet size, suggesting that PEO contributes to improved interfacial stability. These findings highlight the complex interactions between polymers and clay platelets in determining emulsion performance and provide insights into the applications in soft matter, pharmaceutical formulations, and advanced materials.
