Colloids and Interfaces

17 pages, 2567 KB

Open AccessFeature PaperArticle

Transport of Titanium Dioxide Nanoparticles in Porous Media: Characterization and Quantification of Retention Informed by Atomic Force Microscopy

by Hazel Cox and Mark L. Brusseau

Colloids Interfaces 2025, 9(5), 72; https://doi.org/10.3390/colloids9050072 - 17 Oct 2025

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Abstract

Manufactured nanoparticles are used in many consumer products and industries, and are known to enter our waste streams. Transport of nanoparticles in porous media has been studied extensively; however, the forces governing the interactions between nanoparticles and naturally porous media surfaces are still [...] Read more.

Manufactured nanoparticles are used in many consumer products and industries, and are known to enter our waste streams. Transport of nanoparticles in porous media has been studied extensively; however, the forces governing the interactions between nanoparticles and naturally porous media surfaces are still not fully understood. To examine the retention mechanisms and forces involved in nanoparticle transport, miscible–miscible transport experiments were performed and followed by force profile measurements by Atomic Force Microscopy (AFM). TiO₂ nanoparticles were used as the model nanoparticle, with silica sand as the model natural porous medium. Solution chemistries were varied from pH 4.5 (favorable attachment) to 8 (unfavorable attachment), and at 0.0015–30 mM ionic strength. Detachment transport experiments were performed for the unfavorable attachment conditions to determine if secondary minima attachment was present. DLVO calculations were performed to evaluate their predictive ability for force profiles under the experimental conditions. Mass recoveries for the transport experiments ranged from 28% to 80%, indicating significant attachment. Detachment was observed, indicating the presence of secondary minima. The magnitudes of attachment measured for the transport experiments were generally consistent with the results of the AFM measurements. In addition, the detachment observed at the highest pH was also consistent with the predictions, indicating the presence of secondary minima. DLVO theory underestimated the magnitudes of the attractive and repulsive forces measured by AFM but was able to qualitatively represent behavior observed at the lower two pHs. In contrast, it provided a poor representation of behavior at the highest pH. The integrated AFM measurements and miscible–displacement experiments employed in this study have provided insight into the retention of TiO₂, with implications for other nanoparticles during transport in porous media. Full article

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11 pages, 2042 KB

Open AccessArticle

Numerical Simulation of Drying Patterns of Nanofluids in an Open Square Domain

by Zhenlong Song, Yibo Hu and Yanguang Shan

Colloids Interfaces 2025, 9(5), 71; https://doi.org/10.3390/colloids9050071 - 15 Oct 2025

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Abstract

The drying of nanofluid films on a surface can form various patterns and plays an important role in painting, surface patterning, and nano-fabrication processes. In this paper, a two-dimensional Kinetic Monte Carlo (KMC) model is developed based on the two-dimensional Ising model to [...] Read more.

The drying of nanofluid films on a surface can form various patterns and plays an important role in painting, surface patterning, and nano-fabrication processes. In this paper, a two-dimensional Kinetic Monte Carlo (KMC) model is developed based on the two-dimensional Ising model to investigate the drying patterns of nanofluids in an open domain. In the KMC model, the effective chemical potential is approximated by a linear function, in contrast to the constant value used in previous studies. This ensures that the dewetting front in the open domain consistently recedes from the edges toward the center. Simulation results show that nanoparticles, initially uniformly distributed, can assemble into branched structures that remain on the substrate after complete evaporation of the nanofluid. Furthermore, the structures observed in our study differ from the fractal cavities investigated in previous studies conducted in closed domains. A parametric study reveals that both the particle diffusion rate and the chemical potential distribution significantly influence the resulting patterns. Full article

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14 pages, 1599 KB

Open AccessFeature PaperArticle

A SERS Substrate for Ultrafast Photosynthetic Au Nanoparticle Growth on WO₃ Nanowires

by Shiyong Meng, Qingsong Deng, Lin Zhang, Yibo Feng, Lei Fan, Yuxin Liu, Danmin Liu and Cong Wang

Colloids Interfaces 2025, 9(5), 70; https://doi.org/10.3390/colloids9050070 - 14 Oct 2025

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Abstract

The practical adoption of surface-enhanced Raman scattering (SERS) technology is often hampered by the high cost, complex fabrication, and poor reproducibility of conventional substrates, which typically rely on noble metals or inefficient semiconductors. Herein, we address key challenges in the practical commercialization of [...] Read more.

The practical adoption of surface-enhanced Raman scattering (SERS) technology is often hampered by the high cost, complex fabrication, and poor reproducibility of conventional substrates, which typically rely on noble metals or inefficient semiconductors. Herein, we address key challenges in the practical commercialization of surface-enhanced Raman scattering (SERS) technology by reporting a facile, scalable, and environmentally benign strategy for fabricating a hybrid SERS substrate. This approach integrates Au nanoparticles (NPs) with hydrothermally synthesized WO₃ nanowires through a green photoreduction process, which is rapid, organic-solvent-free, and amenable to large-scale production. The design of the Au/WO₃ nanocomposite capitalizes on the synergistic effect between electromagnetic (EM) enhancement from Au NPs and chemical mechanism (CM) enhancement via charge transfer involving the WO₃ semiconductor. This synergy empowers the substrate with exceptional SERS activity, enabling the sensitive detection of Rhodamine 6G (R6G) down to 10⁻¹¹ M and yielding an enhancement factor (EF) of 4.09 × 10⁶. More importantly, this EM-CM synergy proves critical for detecting molecules with weak affinity, such as the nerve agent simulant dimethyl methylphosphonate (DMMP), achieving a significant signal enhancement of 10²–10³ times, which is notably challenging for conventional plasmonic substrates. Beyond sensitivity, the substrate exhibits excellent reproducibility and operational stability, which are paramount for real-world applications. This work presents a nanohybrid strategy that successfully balances scalability, stability, and sensitivity, offering a reliable and cost-effective pathway for advancing SERS technologies toward practical implementation. Full article

(This article belongs to the Special Issue State of the Art of Colloid and Interface Science in Asia)

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25 pages, 3425 KB

Open AccessArticle

Synthesis of Chitosan Nanocomposite Materials Grafted with MWCNTs for the Removal of Tetracycline Pharmaceutical from Water Samples

by Milton Shabeng Kgoete, Conny Putsane Mokgohloa and Lutendo Evelyn Macevele

Colloids Interfaces 2025, 9(5), 69; https://doi.org/10.3390/colloids9050069 - 14 Oct 2025

Viewed by 265

Abstract

Pharmaceutical contaminants such as tetracycline pose an increasing threat to aquatic ecosystems and human health as a result of their persistence in water sources and their contribution to antibiotic resistance. This study developed chitosan nanocomposites by incorporating functionalised and nitrogen-doped multi-walled carbon nanotubes [...] Read more.

Pharmaceutical contaminants such as tetracycline pose an increasing threat to aquatic ecosystems and human health as a result of their persistence in water sources and their contribution to antibiotic resistance. This study developed chitosan nanocomposites by incorporating functionalised and nitrogen-doped multi-walled carbon nanotubes (FMWCNTs and NMWCNTs) for the removal of tetracycline pharmaceutical contaminants from water. The composites were characterised with FTIR, SEM, XRD, BET, UV–Vis, and TGA under various conditions (pH, adsorbent dosage, concentration, contact time, and temperature). Optimal tetracycline removal (85%) was achieved with pH 6, 2 g/L adsorbent dose, 10 ppm concentration, and 30 min contact time. The FMWCNT–chitosan composite could be recycled five times with an adsorption loss of only 2%. The FMWCNT–chitosan composite showed the good adsorption efficiency of 82% in the presence of counter ions and 70% in a binary system. The adsorption process followed the Langmuir isotherm (263 mg/g), indicative of monolayer adsorption and pseudo-second-order kinetics. Among the nanocomposites prepared, the FMWCNT–chitosan composite showed the highest performance, removing more than 85% of tetracycline from water samples. Full article

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16 pages, 3215 KB

Open AccessFeature PaperArticle

Adsorption and Dilational Viscoelasticity of Saponin at the β-Pinene/Water and Air/Water Interfaces

by Feng Lin

Colloids Interfaces 2025, 9(5), 68; https://doi.org/10.3390/colloids9050068 - 11 Oct 2025

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Abstract

Understanding adsorption and interfacial properties of surface-active agents at interfaces is crucial to the formation and stability of colloidal systems such as emulsions and foams. In this work, interfacial tension and viscoelasticity of saponin at the β-pinene/water interface were studied using drop tensiometry [...] Read more.

Understanding adsorption and interfacial properties of surface-active agents at interfaces is crucial to the formation and stability of colloidal systems such as emulsions and foams. In this work, interfacial tension and viscoelasticity of saponin at the β-pinene/water interface were studied using drop tensiometry and dilational rheology measurement. For comparison, saponin at the air/water interface was also evaluated. Both saponin and β-pinene are bio-based, eco-friendly, and abundant in plants, trees, and agricultural wastes. Results showed that dynamic interfacial tensions σ(t) of saponin adsorbed at β-pinene/water and air/water interfaces could be well described by the Ward and Tordai model, suggesting that the saponin adsorption kinetics at both interfaces are controlled by a kinetically limited mechanism. The equilibrium interfacial pressure π_e data prior to critical micelle concentration (cmc) were adequately fitted by the Gibbs adsorption isotherm. At the β-pinene/water interface, a higher cmc and a larger area per molecule, but a lower π_e, were observed compared to the air/water interface. Interestingly, the dilational moduli of saponin at β-pinene/water increased with increasing oscillating frequency, but with less significant frequency dependence than their counterparts at the air/water interface. The dilational moduli of saponin at β-pinene/water passed through a minimum with increasing saponin bulk concentration, while the air/water interface exhibited a strikingly different trend in terms of concentration dependence and a higher magnitude for the dilational moduli. The correlation between adsorption behaviors and dilational properties of saponin at the two interfaces is discussed. Fundamental knowledge gained from this study will be beneficial for the rational development of new biocompatible emulsions and foam products for more sustainable applications. Full article

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14 pages, 1417 KB

Open AccessFeature PaperArticle

Surface Aggregation Adsorption of Binary Solutions Between Diiodomethane, Furfural, and N,N-Dimethylformamide

by Zhongwei Huang, Na Du and Wanguo Hou

Colloids Interfaces 2025, 9(5), 67; https://doi.org/10.3390/colloids9050067 - 9 Oct 2025

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Abstract

The surface tensions (σ) of binary solutions of diiodomethane (DIM, 1)–furfural (FA, 2), DIM (1)–N,N-dimethylformamide (DMF, 2), and FA (1)–DMF (2) were determined at 25 °C over the entire bulk composition range, and the surface adsorption behavior [...] Read more.

The surface tensions (σ) of binary solutions of diiodomethane (DIM, 1)–furfural (FA, 2), DIM (1)–N,N-dimethylformamide (DMF, 2), and FA (1)–DMF (2) were determined at 25 °C over the entire bulk composition range, and the surface adsorption behavior was analyzed using the surface aggregation adsorption (SAA) model proposed recently. In particular, by combining the SAA model with the Gibbs adsorption equation, the changes in the Gibbs surface excess (Γ₂) and the adsorption layer thickness (τ) with the bulk composition (x_2,b) were investigated. The SAA model combined with the modified Eberhart model can well describe the σ-isotherms of the three binary solutions. The surface adsorption trends of component 2 in DIM–FA, DIM–DMF, and FA–DMF decrease in turn. The change trends of Γ₂ and τ with x_2,b are dependent on the SAA model parameters, namely, the adsorption equilibrium constant (K_x) and the average aggregation number (n). With an increase in x_2,b, Γ₂ continuously increases when K_x < 2v₁/[n(2n − 1)v₂] (where v₁ and v₂ are the partial molar volumes of components 1 and 2, respectively); otherwise (i.e., K_x ≥ 2v₁/[n(2n − 1)v₂]), Γ₂ initially increases and then decreases, showing a maximum on the Γ₂-isotherm. When n ≥ 1, τ gradually decreases with an increase in x_2,b; otherwise (i.e., n < 1), τ initially increases and then decreases, showing a maximum on the τ-isotherm. An increase in the adsorption trend leads to a decrease in both Γ₂ and τ. This work provides a better understanding of the surface adsorption behavior of liquid mixtures. Full article

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15 pages, 4895 KB

Open AccessArticle

Magnetic Thixotropic Fluid for Direct-Ink-Writing 3D Printing: Rheological Study and Printing Performance

by Zhenkun Li, Tian Liu, Hongchao Cui, Jiahao Dong, Zijian Geng, Chengyao Deng, Shengjie Zhang, Yin Sun and Heng Zhou

Colloids Interfaces 2025, 9(5), 66; https://doi.org/10.3390/colloids9050066 - 2 Oct 2025

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Abstract

Yield stress and thixotropy are critical rheological properties for enabling successful 3D printing of magnetic colloidal systems. However, conventional magnetic colloids, typically composed of a single dispersed phase, exhibit insufficient rheological tunability for reliable 3D printing. In this study, we developed a novel [...] Read more.

Yield stress and thixotropy are critical rheological properties for enabling successful 3D printing of magnetic colloidal systems. However, conventional magnetic colloids, typically composed of a single dispersed phase, exhibit insufficient rheological tunability for reliable 3D printing. In this study, we developed a novel magnetic colloidal system comprising a carrier liquid, magnetic nanoparticles, and organic modified bentonite. A direct-ink-writing 3D-printing platform was specifically designed and optimized for thixotropic materials, incorporating three distinct extruder head configurations. Through an in-depth rheological investigation and printing trials, quantitative analysis revealed that the printability of magnetic colloids is significantly affected by multiple factors, including magnetic field strength, pre-shear conditions, and printing speed. Furthermore, we successfully fabricated 3D architectures through the precise coordination of deposition paths and magnetic field modulation. This work offers initial support for the material’s future applications in soft robotics, in vivo therapeutic systems, and targeted drug delivery platforms. Full article

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22 pages, 5277 KB

Open AccessFeature PaperArticle

Colloidal Properties of Clays from Ventzia Basin Enhanced with Chemical Additives and Subjected to Dynamic Thermal Aging Suitable for Water-Based Drilling Fluids

by Dimitriοs Papadimitriou, Ernestos-Nikolas Sarris, Andreas Georgakopoulos and Nikolaos Kantiranis

Colloids Interfaces 2025, 9(5), 65; https://doi.org/10.3390/colloids9050065 - 28 Sep 2025

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Abstract

This work examines the colloidal properties of clays sampled from two different locations in Ventzia basin processed as low-density solid additives for water-based drilling fluid applications. The obtained samples were mechanically processed to reach a size less than 2 cm. The material was [...] Read more.

This work examines the colloidal properties of clays sampled from two different locations in Ventzia basin processed as low-density solid additives for water-based drilling fluid applications. The obtained samples were mechanically processed to reach a size less than 2 cm. The material was then activated with 3 wt% soda ash without oven drying, keeping the moisture in environmental conditions to simulate industrial activation conditions. After laying for one month curing time, samples were oven dried at 60 °C and further ground to <120 μm. Two groups of samples were created mixing clays from Ventzia basin and additives. The first group contained clay, xanthan gum and sodium polyacrylate (PAA), while the second group contained clay, xanthan gum and sodium hexametaphosphate (SHMP). Standard tests were performed for the rheological behavior and filtration properties prior to and after dynamic thermal aging. Results obtained were compared with commercial clays from Milos and Wyoming used in drilling fluid systems, after thermally deteriorating also their properties. The obtained results revealed that the enhanced clays under study maintain excellent thermal stability. Notably, the top-performing formulation met the critical American Petroleum Institute (API) benchmark for filtrate loss (<15 mL) and exhibited a robust rheological profile at temperatures up to 105 °C, demonstrating its suitability for water-based fluid (WBF) applications. Full article

(This article belongs to the Special Issue Colloids and Interfaces in Mineral Processing)

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14 pages, 1581 KB

Open AccessArticle

Physicochemical Morphological Evaluation and Stability Assessment of Nanoemulsions Containing Nutrients for Parenteral Nutrition

by Panos Papandreou, Efstathia Triantafyllopoulou, Ioannis Pispas, Sophia Havaki, Aristeidis Papagiannopoulos, Vassilis G. Gorgoulis and Natassa Pippa

Colloids Interfaces 2025, 9(5), 64; https://doi.org/10.3390/colloids9050064 - 25 Sep 2025

Viewed by 332

Abstract

Parenteral nutrition is an integral part of the nutritional support of critically ill neonates, infants, and children in the intensive care units (ICUs) and at home. Therefore, the adequacy and the effectiveness of parenteral nutrition, PN, support are among the major concerns of [...] Read more.

Parenteral nutrition is an integral part of the nutritional support of critically ill neonates, infants, and children in the intensive care units (ICUs) and at home. Therefore, the adequacy and the effectiveness of parenteral nutrition, PN, support are among the major concerns of doctors and pharmacists. The aim of this study is the physicochemical and stability evaluation of nanoemulsions, which are used for parenteral nutrition. These nanoemulsions are for intravenous (IV) administration of lipids, amino acids, glucose, electrolytes, trace elements as well as vitamins. Light scattering techniques are used for the identification of the hydrodynamic diameter (D_h), size polydispersity index (PDI), and the ζ-potential of the prepared nanoemulsions. Stability assessment is performed in different conditions, mimicking those of the hospital. The stability studies involve shelf-life measurement of these NEs over 10 days in two storage conditions (25 °C and 4 °C) using dynamic light scattering. According to the US Pharmacopeia, the droplet size should be under the upper limit of 500 nm (0.5 μm). Transmission electron microscopy (TEM) is used for the shape of the droplets of the nanoemulsion emulsion for parenteral nutrition for the first time. The results showed that the droplet size was around 300 nm, with a homogeneous population and negative ζ-potential. The morphology was vesicular and spherical, typical for NE droplet shape. The results from all the characterization techniques show that the formulations meet the high-quality standards of nanoemulsions for neonates, infants and children. Full article

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30 pages, 10154 KB

Open AccessFeature PaperReview

Two-Dimensional Materials for Selective Ion Transport Membrane: Synthesis and Application Advances

by Zhijian Jiang, Shining Zhang, Jianzhi Xu, Ying Liu, Yuanyuan Zhang, Jianguo Liu and Zicheng Zuo

Colloids Interfaces 2025, 9(5), 63; https://doi.org/10.3390/colloids9050063 - 17 Sep 2025

Viewed by 953

Abstract

Membrane innovations have become a key solution for overcoming the bottlenecks in efficiency upgrade in many green energy fields. Membrane performance depends on two key parameters permeability and selectivity, which typically follow a trade-off relationship: improving one often diminishes the other. Two-dimensional (2D) [...] Read more.

Membrane innovations have become a key solution for overcoming the bottlenecks in efficiency upgrade in many green energy fields. Membrane performance depends on two key parameters permeability and selectivity, which typically follow a trade-off relationship: improving one often diminishes the other. Two-dimensional (2D) materials, which have atomic-level thickness, tunable pore sizes, and reasonable functionalization, offer great promises to break through the trade-off effect and redesign high-efficiency mass transfer pathways. This review systematically presents recent efforts in both preparation and potential applications of 2D materials for overcoming the permeability–selectivity trade-off. It highlights four prevailing fabrication strategies: chemical vapor deposition, interfacial synthesis, solution-phase synthesis, and exfoliation, and shows some major optimization techniques for various 2D materials. Additionally, this review discusses emerging applications of 2D materials across critical fields from water treatment (seawater desalination, metal ion extraction) to energy technologies (osmotic power generation, direct methanol fuel cells, and vanadium redox flow batteries). Finally, the challenges and future prospects of 2D materials in ion separation and energy conversion are discussed. Full article

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17 pages, 4099 KB

Open AccessArticle

Synthesis of Quaternary Ammonium Gemini Levelers and Their Action Mechanisms in Microvias Void-Free Copper Filling

by Tao Song, Jun-Yi Wang, Jiang-Peng Qiu, Jia-Qiang Yang, Zhao-Yun Wang, Yi Zhao, Xiao-Hui Yang, Ren Hu, Jun Cheng, Fang-Zu Yang, Lian-Huan Han and Dong-Ping Zhan

Colloids Interfaces 2025, 9(5), 62; https://doi.org/10.3390/colloids9050062 - 15 Sep 2025

Viewed by 447

Abstract

Developing a highly efficient leveler in acid copper electroplating solution is one of the primary tasks necessary for achieving superconformal filling of microvias and interconnections in printed circuit boards (PCBs). Two triethylenediamine-based Gemini levelers, both with terminal quaternary ammonium groups, are synthesized and [...] Read more.

Developing a highly efficient leveler in acid copper electroplating solution is one of the primary tasks necessary for achieving superconformal filling of microvias and interconnections in printed circuit boards (PCBs). Two triethylenediamine-based Gemini levelers, both with terminal quaternary ammonium groups, are synthesized and named as GL1 (C8) after reaction of triethylenediamine with 1,8-dichlorooctane and GL2 (C6 with two C–O linkages) after triethylenediamine with 1,2-bis(2-chloroethoxy) ethane. Electrochemical experiments indicate that at 100 rpm and 1000 rpm GL2 combines with a suppressor and accelerator to exhibit greater potential difference of 23 mV than GL1 in 9 mV for Cu²⁺ reduction, demonstrating that GL2 has a stronger synergistic convection-dependent adsorption (CDA) effect. Microvias copper electroplating experiments confirm that acid copper electroplating solution containing GL2 achieve more effective superconformal void-free filling as it results in FP = 96.1%, while the solution containing GL1 results in FP = 70%. Theoretical calculations indicate that adsorption energy of GL2 is −1037.54 kJ·mol⁻¹, which is lower than GL1 (−1019.06 kJ·mol⁻¹). GL2 displays lower electron density compared to GL1, which facilitates its displacement by accelerator at the bottom. The lower adsorption energy of GL2 suggests the weaker adsorption ability and the stronger CDA behavior. Full article

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18 pages, 670 KB

Open AccessReview

Recent Developments and Applications of Food-Based Emulsifiers from Plant and Animal Sources

by Yuqiao Jin and Achyut Adhikari

Colloids Interfaces 2025, 9(5), 61; https://doi.org/10.3390/colloids9050061 - 10 Sep 2025

Viewed by 1871

Abstract

Food-based emulsifiers, derived from natural or edible sources such as soybeans, oats, eggs, milk, and fruits, have gained increasing attention in the food industry due to their clean label appeal, recognition as natural ingredients, and alignment with consumer demand for fewer synthetic additives. [...] Read more.

Food-based emulsifiers, derived from natural or edible sources such as soybeans, oats, eggs, milk, and fruits, have gained increasing attention in the food industry due to their clean label appeal, recognition as natural ingredients, and alignment with consumer demand for fewer synthetic additives. These emulsifiers are also valued for their biodegradability, environmental sustainability, and potential nutritional benefits. The food-based compounds have been extensively studied for their functional and physicochemical properties. This review provides a comprehensive overview of recent developments and applications of food-based emulsifiers, with a focus on protein-based, polysaccharide-based, and phospholipid-based emulsifying agents derived from plant and animal sources. The mechanisms, advantages, and disadvantages of the food-based emulsifiers are discussed. Plant-based emulsifiers offer sustainability, wide availability, and cost-efficiency, positioning them as a promising area for research. Combinations of food-based emulsifiers such as polysaccharides, proteins, and phospholipids can be utilized to enhance emulsion stability. This paper evaluates current literature and discusses future challenges and trends in the development of food-based emulsifiers. Full article

(This article belongs to the Special Issue Recent Advances on Emulsions and Applications: 3rd Edition)

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11 pages, 10408 KB

Open AccessCommunication

Leaving Glauber’s Salt Island: The Road to Stabilisation

by Poppy O’Neill, Anastasia Stamatiou and Ludger Fischer

Colloids Interfaces 2025, 9(5), 60; https://doi.org/10.3390/colloids9050060 - 9 Sep 2025

Viewed by 571

Abstract

Glauber’s salt is a promising phase change material for thermal energy storage due to its high latent heat capacity of 234 J/g and melting point of 34 °C, making it well-suited for low-temperature heating applications. However, its practical use has been limited by [...] Read more.

Glauber’s salt is a promising phase change material for thermal energy storage due to its high latent heat capacity of 234 J/g and melting point of 34 °C, making it well-suited for low-temperature heating applications. However, its practical use has been limited by phase separation and associated loss of performance during repeated thermal cycling. This study aimed to address this limitation through a novel stabilisation approach. The material was encapsulated within an emulsion matrix designed to physically constrain the salt and inhibit separation during melting and to form a phase change dispersion. The phase change dispersion was subjected to 100 controlled heating–cooling cycles whilst monitoring the latent heat capacity and phase transition plateaus. The phase change dispersion retained its thermal properties throughout testing, showing no measurable degradation in storage capacity nor shift in phase transition temperature. These results demonstrate that this encapsulation mechanism can effectively maintain the functional performance of Glauber’s salt under repeated thermal cycling. This approach may form the basis for more durable salt hydrate-based storage media and has potential relevance for applications in building heating, waste heat recovery and renewable energy integration. By improving stability, this method helps unlock the long-term operational viability of phase change materials. Full article

(This article belongs to the Special Issue Recent Advances on Emulsions and Applications: 3rd Edition)

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12 pages, 2456 KB

Open AccessArticle

Drying Molybdate/Iron Hydroxide Interface Leading to Both Inner- and Outer-Sphere Surface Complexes Depending on Initial Concentrations

by Romain Botella and Grégory Lefèvre

Colloids Interfaces 2025, 9(5), 59; https://doi.org/10.3390/colloids9050059 - 5 Sep 2025

Viewed by 423

Abstract

Drying is ubiquitous. However, its influence on surface speciation has been seldom studied. Through an in situ Attenuated Total Reflection–Infrared (ATR-IR) spectroscopy analysis of the drying of molybdate solutions on a lepidocrocite particle film, the change in surface speciation is followed. No formation [...] Read more.

Drying is ubiquitous. However, its influence on surface speciation has been seldom studied. Through an in situ Attenuated Total Reflection–Infrared (ATR-IR) spectroscopy analysis of the drying of molybdate solutions on a lepidocrocite particle film, the change in surface speciation is followed. No formation polymolybdates nor precipitate are observed upon drying at pH 8. An in situ washing of the dried solid/solution interface unveils the existence of surface outer-sphere and inner-sphere complexes. Decreasing the molybdate concentration highlights a saturation effect of the surface upon drying. Moreover, the careful analysis of substrate IR bands showed non-uniform drying which is an important insight to understand dehydration chemistry. The remaining molybdate ions at the surface as inner-sphere complexes are present as binuclear monodentate complexes stabilized by sodium. Full article

(This article belongs to the Special Issue Ten Years Without Nikola Kallay)

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17 pages, 5055 KB

Open AccessArticle

Removal of Copper (II) from Aqueous Solutions Using Silica Xerogel as Sorbent: Adsorption Properties and Mechanism

by Ammaeva Shanaz, Isaev Abdulgalim, Schubert Richard, Pankov Ilya and Talanov Valery

Colloids Interfaces 2025, 9(5), 58; https://doi.org/10.3390/colloids9050058 - 1 Sep 2025

Viewed by 805

Abstract

The contamination of water resources with heavy metals creates problems for using it as a source of drinking water. Adsorption is one of the most promising methods for heavy metal ion removal from natural and wastewater. The process of removing copper (II) from [...] Read more.

The contamination of water resources with heavy metals creates problems for using it as a source of drinking water. Adsorption is one of the most promising methods for heavy metal ion removal from natural and wastewater. The process of removing copper (II) from aqueous solutions using SiO₂ xerogel as an adsorbent has been studied. The xerogel was thoroughly characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and argon adsorption–desorption isotherms, revealing an amorphous structure with a high surface area (~347 m²/g) and uniform mesoporosity (2–14 nm pore size). The surface chemistry, dominated by silanol groups, was confirmed by XPS analysis. The adsorption process is influenced by electrostatic interactions between the positively charged Cu(II) ions and the negatively charged surface groups, with the optimal performance near neutral pH. Batch adsorption experiments demonstrated that the silica xerogel effectively removes Cu(II) ions from aqueous solutions, with removal efficiency exceeding 99% at pH values above 4.0. The maximum adsorption capacity of copper (II) ions on SiO₂ xerogel is 67.5 mg/L. Full article

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15 pages, 4888 KB

Open AccessFeature PaperArticle

Rapid Removal of Sizing Agent from Carbon Fiber Surface by Liquid-Phase Plasma Electrolysis

by Chiyuhao Huang, Qian Zhou, Maoyuan Li, Xiaolin Wei, Dongqin Li, Xin He and Weiwei Chen

Colloids Interfaces 2025, 9(5), 57; https://doi.org/10.3390/colloids9050057 - 1 Sep 2025

Viewed by 615

Abstract

In this study, liquid-phase plasma electrolysis (LPE) was successfully employed to remove the sizing agent from T800 carbon fiber surfaces. Through systematic investigation of varying arcing voltages (185–215 V) and electrode spacings (10–20 mm), we determined that an optimal combination of 200 V [...] Read more.

In this study, liquid-phase plasma electrolysis (LPE) was successfully employed to remove the sizing agent from T800 carbon fiber surfaces. Through systematic investigation of varying arcing voltages (185–215 V) and electrode spacings (10–20 mm), we determined that an optimal combination of 200 V and 10 mm spacing achieved near-complete sizing removal, as confirmed by SEM, TGA, and XPS analyses. Under this condition, plasma bombardment dominated the removal mechanism, eliminating sizing residues while exposing the underlying fiber grooves. TGA further demonstrated that in samples treated at a 10 mm interval, the weight loss of LPE samples before 300 °C was negligible, indicating that the sizing agent had been thoroughly removed. The results of XPS further confirmed the high efficiency of LPE in the removal of sizing agents (C-O bond content from 41.6% to 26.9%), and the retention of C-O also proved that LPE could maintain the surface activity of carbon fibers, confirming the effectiveness of LPE in decomposing the sizing agent. Meanwhile, based on the above test results, an attempt was made to explain the mechanism of LPE in removing sizing agents from the surface of carbon fibers. Full article

(This article belongs to the Special Issue State of the Art of Colloid and Interface Science in Asia)

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17 pages, 1931 KB

Open AccessArticle

Improvement in the Stability of Perilla Seed Oil Microemulsion and Its Role in Fat Accumulation Reduction in Caenorhabditis elegans

by Junwei Pan, Yunzhou Tang, Ziqing Liang, Yong Cao and Yunjiao Chen

Colloids Interfaces 2025, 9(5), 56; https://doi.org/10.3390/colloids9050056 - 30 Aug 2025

Viewed by 495

Abstract

Perilla seed oil (PSO) possesses various physiological functions, such as lowering blood lipids and preventing cancer; however, its poor water solubility, dispersibility, and oxidative stability severely limit its application scope. Epigallocatechin gallate (EGCG) is a natural antioxidant abundant in tea leaves. In this [...] Read more.

Perilla seed oil (PSO) possesses various physiological functions, such as lowering blood lipids and preventing cancer; however, its poor water solubility, dispersibility, and oxidative stability severely limit its application scope. Epigallocatechin gallate (EGCG) is a natural antioxidant abundant in tea leaves. In this study, PSO–casein–EGCG microemulsions were prepared, and their stability and lipid-lowering effects were evaluated. The results showed that the PSO microemulsion had a particle size of 361.23 ± 14.85 nm, a zeta potential of −20.77 ± 0.68 mV, a polydispersity index (PDI) of 0.17 ± 0.07, and an encapsulation efficiency of 94.3%. PSO microemulsions remained stable at room temperature for 5 days without droplet aggregation. The stability of the microemulsions was good when the NaCl concentration was between 0.1 and 1 mM and the pH was between 5 and 9. PSO microemulsions enhanced the oxidative stability of PSO. Additionally, PSO microemulsions significantly reduced triglyceride levels in Caenorhabditis elegans (77.50%, p < 0.005). Finally, it was found that the average lipid droplet size of ZXW618 mutant nematodes decreased by 41.23% after PSO microemulsion treatment. Therefore, PSO microemulsions may reduce fat accumulation in C. elegans by decreasing lipid droplet size. This provides new insights for advancing the application of PSO in the food processing industry. Full article

(This article belongs to the Special Issue Recent Advances on Emulsions and Applications: 3rd Edition)

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20 pages, 3265 KB

Open AccessArticle

Phytochemical-Assisted Fabrication of Biogenic Silver Nanoparticles from Vitex negundo: Structural Features, Antibacterial Activity, and Cytotoxicity Evaluation

by Mohit Yadav, Nisha Gaur, Nitin Wahi, Sandeep Singh, Krishan Kumar, Azadeh Amoozegar and Eti Sharma

Colloids Interfaces 2025, 9(5), 55; https://doi.org/10.3390/colloids9050055 - 28 Aug 2025

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Abstract

Multidrug resistance (MDR) is an emerging global health concern worldwide, driving the need for innovative solutions. Herbal approaches are gaining attention and acceptance due to safer profiles and very few side effects. In this study, silver nanoparticles (VN-AgNPs) were synthesized using Vitex negundo [...] Read more.

Multidrug resistance (MDR) is an emerging global health concern worldwide, driving the need for innovative solutions. Herbal approaches are gaining attention and acceptance due to safer profiles and very few side effects. In this study, silver nanoparticles (VN-AgNPs) were synthesized using Vitex negundo, a medicinally valuable plant. A methanolic extract was prepared from Vitex negundo and the phytochemical evaluation confirmed the presence of flavonoids, alkaloids, and terpenoids, with quantitative analysis revealing high total phenolic content (TPC: 23.59 mg GAE/g) and total flavonoid content (TFC: 45.23 mg rutin/g), both maximized under microwave-assisted extraction (MAE). The antioxidant activity was also highest (18.77 mg AA/g). Characterization of the optimized extract by GC–MS identified various bioactive compounds. VN-AgNPs were synthesized using the aqueous leaf extract under specified conditions and were structurally characterized using many techniques and evaluated for antibacterial activity against four bacterial strains. VN-AgNPs exhibited significant antibacterial efficacy with inhibition zones measuring 16 ± 0.87 mm against Bacillus (Gram-positive), 15 ± 0.46 mm against E. coli (Gram-negative), 12 ± 0.64 mm against Pseudomonas (Gram-negative), and 11 ± 0.50 mm against Pectobacterium (Gram-negative plant pathogen). These findings highlight the efficacy of green-synthesized VN-AgNPs as a promising alternative to combat MDR pathogens, paving the way for sustainable and effective antimicrobial strategies. Full article

(This article belongs to the Special Issue Biocolloids and Biointerfaces: 2nd Edition)

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22 pages, 2212 KB

Open AccessArticle

Bemotrizinol-Loaded Lipid Nanoparticles for the Development of Sunscreen Emulsions

by Maria Grazia Sarpietro, Debora Santonocito, Giuliana Greco, Stefano Russo, Carmelo Puglia and Lucia Montenegro

Colloids Interfaces 2025, 9(5), 54; https://doi.org/10.3390/colloids9050054 - 26 Aug 2025

Viewed by 883

Abstract

In this work, bemotrizinol (BMTZ), a broad-spectrum UV-filter, was loaded into nanostructured lipid carriers (NLC) whose lipid matrix contained different oils (isopropyl myristate, decyl oleate, caprylic/capric triglyceride) to assess the effects of the lipid core composition on the properties of the resulting NLC. [...] Read more.

In this work, bemotrizinol (BMTZ), a broad-spectrum UV-filter, was loaded into nanostructured lipid carriers (NLC) whose lipid matrix contained different oils (isopropyl myristate, decyl oleate, caprylic/capric triglyceride) to assess the effects of the lipid core composition on the properties of the resulting NLC. Subsequently, the effects of incorporating different concentrations of optimized BMTZ-loaded NLC on the technological properties of O/W emulsions (pH, viscosity, spreadability, occlusion factor, in vitro BMTZ release, skin permeation, and in vitro sun protection factor) were assessed. The optimized BMTZ-loaded NLC contained 3.0% w/w of isopropyl myristate and showed mean size = 190.6 ± 9.8 nm, polydispersity index = 0.153 ± 0.013, ζ-potential = −10.6 ± 1.7 mV, and loading capacity = 8% w/w. The incorporation of increasing concentrations (5, 10, 20% w/w) of optimized BMTZ loaded into emulsions provided a slight increase in spreadability, lower viscosity, and no change in pH, occlusion factor, and BMTZ release compared to emulsions containing free BMTZ. No BMTZ skin permeation was observed from all formulations. About a 20% increase in sun protection factor values was obtained for vehicles containing BMTZ-loaded NLC compared with formulations incorporating the same amount of free BMTZ. Therefore, incorporating BMTZ-loaded NLC into emulsions could be a promising strategy to develop safer and more effective sunscreen formulations. Full article

(This article belongs to the Special Issue Recent Advances on Emulsions and Applications: 3rd Edition)

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Colloids Interfaces, Volume 9, Issue 5 (October 2025) – 19 articles

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