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The growing awareness of the adverse health effects of trans-fats and saturated fats are driving researchers to seek healthy alternatives. A promising strategy to structure liquid oil, called oleogelation, has been a subject of great interest. In the development of oleogels, highly unsaturated oils can be structured through different gelation mechanisms by varying structuring agents (e.g., polymeric or low molecular weight oleogelators). Due to their potential to reduce saturated fat in food products while also providing solid texture without changing the oil's chemical composition and nutritional values, oleogels have been introduced into various products (meat, spread, and confectionary) as alternatives to traditional solid fats. However, the shortcomings of oleogels cannot be ignored, such as the softer texture and the poorer plasticity than traditional solid fat. As the physicochemical properties and functionalities of oleogels are highly dependent on their composition and structuring mechanism, it is possible to obtain a product with desirable functionality by choosing a suitable oleogelator or oil phase. Thus, comprehensive and detailed knowledge regarding the role of oleoglarors, oil phase, and oleogelation mechanism on oleogelation is needed. This review primarily focuses on published information within the last decades addressing how the composition and oleogelation mechanism affect the structure and functionality of oleogels and oleogel-based products. The factors affecting the oil gelation are summarized concerning three aspects: (i) oleogelator (chemical composition and molecular structure); (ii) oil phase (TAG composition and minor component); and (iii) oleogelation mechanism. Finally, the future perspectives toward oleogels are highlighted. This review aims to deepen the understanding of oleogelation and the rational design of oleogel-based products.

We observe the impact of bouncing and floating of water drops on a pool of immiscible volatile oil pools at low Weber numbers. The residence time of the impacting drop ranges from a few milliseconds to a few seconds before it sinks into the lighter oil phase. It is hypothesized that the confined evaporation from the volatile oil pool replenishes the thin film draining and results in prolonged floating and delayed sinking of drops into the oil pool. Water drops are released from a low height to impact on volatile hydrocarbon oil deep pools of various volatilities. The floating dynamics and residence times are captured using high-speed imaging. A theoretical model for the residence time has been developed to evaluate the hypothesis. The drop residence time is found to be directly proportional to the volatility of the oil pool in accordance with the hypothesis. The mathematical model incorporating the coupled confined evaporation and film draining dynamics is found to be in well agreement with the experimentally observed residence time. The bouncing-sinking regime map has been developed based on the experimental data.

The results of studies on the development of micro-oscillators (MOs) based on the Belousov –Zhabotinsky (BZ) oscillatory chemical reaction are integrated and systematized. The mechanisms of the BZ reaction and the methods of immobilization of the catalyst of the BZ reaction in micro-volumes are briefly discussed. Methods for creating BZ MOs based on water microdroplets in the oil phase and organic and inorganic polymer microspheres are considered. Methods of control and management of the dynamics of BZ MO networks are described, including methods of MO synchronization. The prospects for the design of neural networks of MOs with intelligent-like behaviour are outlined. Such networks present a new area of nonlinear chemistry, including, in particular, the creation of a chemical ‘computer’. The bibliography includes 250 references.

The object of research is the filtration processes of displacement of the oil phase under the influence of an injection well in a heterogeneous porous medium. It is possible to evaluate and take into account the effect of reservoir heterogeneity on the distribution of reservoir pressure (and, consequently, on the intensity of the filtration process) using numerical modeling of filtration processes based on the piezoelectric equation. To solve the non-stationary anisotropic problem of piezoconductivity, it is proposed to apply the combined finite-element-difference method of M.Lubkov, which makes it possible to take into account the inhomogeneous distribution of permeability inside the anisotropic oil-bearing formation and at its boundaries, and to adequately calculate the distribution of reservoir pressure. The use of the combined finite-element-difference method allows to combine the advantages of the finite-element method and the finite difference method: to model geometrically complex areas, to find the value at any point of the object under study. At the same time, the use of an implicit difference scheme when finding the nodal values of the grid provides high reliability and convergence of the results. The simulation results show that the distribution of the pressure field between the production and injection wells significantly depends on their location, both in the isotropic landslide and in the anisotropic oil-bearing reservoir. It is shown that the distance between the wells of more than 1 km levels out the effectiveness of the impact of the injection well on the oil filtration process. The influence of the permeability of the oil phase in the shear direction dominates the influence of the permeability in the axial directions (affects the pressure decrease by 4–9.5%). In the case of a landslide-isotropic reservoir, the wells should be located in the shear (diagonal) direction, which will provide the lowest level of drop in the average reservoir pressure (by 4%). Based on the information obtained, for the effective use of anisotropic low-permeability formations, it is necessary to place production and injection wells in areas with relatively low anisotropy of the formation permeability, especially to avoid places with the presence of landslide permeability of the formation. The location of the wells is important so that, on the one hand, there is no blockage of oil from the side of reduced permeability, and on the other hand, rapid depletion of the formation from the side of increased permeability does not occur. And also the mutual exchange between the production and injection wells did not stop. When placing a system of production and injection wells in anisotropic formations of an oil field, it is necessary to carry out a systematic analysis of the surrounding anisotropy of the formations in order to place them in such a way that would ensure effective dynamics of filtration processes around these wells. Using the method used, it is possible to predict the impact of an injection well on the distribution of reservoir pressure in the reservoir.

Microfluidic on-chip production of microgels employing external gelation has numerous biological and pharmaceutical applications, particularly for the encapsulation of delicate cargos; however, the on-chip production of microgels in microfluidic devices can be challenging due to problems such as clogging caused by accelerated progress in precursor solution viscosity. Here, we introduce a novel microfluidic design incorporating two consecutive coflow geometries for microfluidic droplet generation. A shielding oil phase is employed to avoid emulsification and gelation stages from occurring simultaneously, thereby preventing clogging. The results revealed that the microfluidic device could generate highly monodispersed spherical droplets (coefficient of variation < 3%) with an average diameter in the range of 60-200 μm. Additionally, it was demonstrated that the device could appropriately create a shelter of the oil phase around the inner aqueous phase regardless of the droplet formation regime and flow conditions. The ability of the proposed microfluidic device in the generation of microgels was validated by producing alginate microgels utilizing an aqueous solution of calcium chloride as the continuous phase.

Interfacial chemical dynamics on a droplet generate various self-propelled motions. For example, ballistic and random motions arise depending on the physicochemical conditions inside the droplet and its environment. In this study, we focus on the relationship between oxidant concentrations in an aqueous droplet and its mode of self-propelled motion in an oil phase including surfactant. We demonstrated that the chemical conditions inside self-propelled aqueous droplets were changed systematically, indicating that random motion appeared at higher concentrations of oxidants, which were H2SO4 and BrO3-, and ballistic motion at lower concentrations. In addition, spontaneous mode switching from ballistic to random motion was successfully demonstrated by adding malonic acid, wherein the initially observed reduced state of the aqueous solution suddenly changed to the oxidized state. Although we only observed one-time transition and have not yet succeeded to realize alternation between ballistic (reduced state) and random motion (oxidized state), such spontaneous transitions are fundamental steps in realizing artificial cells and understanding the fundamental mechanisms of life-like behavior, such as bacterial chemotaxis originating from periodical run-and-tumble motion.

Aim: This study aimed to investigate the influence of the preparation process and composition on the microstructure of the O/W primary emulsions and the corresponding impact on the formation of oil-in-water-in-oil (O/W/O) multiple emulsions. Objectives: Multiple emulsions were prepared by a two-step emulsification method and the microstructure was characterized by the microscope. Methods: The primary emulsion was prepared by four kinds of preparation methods, which include both high-energy and low-energy emulsification, and then the primary emulsion was re-emulsified by stirring in the outer phase. Result: Through the theoretical investigation and the corresponding verification experiments of the interfacial film, the geometric reason for O/W/O multiple emulsion which was relatively difficult to prepare has been found. The microstructure of O/W particles was more obvious, and the particle size became smaller with the increase of the hydrophilic emulsifier amount beneficial to the formation and stability of O/W/O structures. However, the excess emulsifier that existed in the water phase could interfere the stability of the W/O interface. Moreover, the viscosity of inner oil phase had a large influence on the formation of O/W/O emulsion by affecting the particle size of the primary emulsion and the dynamic equilibrium between the inner and outer oil phase. Conclusion: It can be concluded that fine multiple emulsions were formed when the particle size of the primary emulsion was moderate since the large particles would break through the outer interface membrane and small particles would combine with the outer oil phase due to the Ostwald ripening.

The antioxidizing capability of membrane antioxidants is strongly affected by the submolecular regions of the membrane that they locate. However, the concurrent determination of their location in the membranes and the consequent antioxidizing effect remains difficult. Using our field-induced droplet ionization mass spectrometry methodology, here we show the rapid determination of the antioxidation effect and the spatial distribution of melatonin in POPC membranes. Melatonin effectively protects the membrane lipids against hydroxyl radicals originating from the Fenton reactions in the water phase but cannot protect the lipids against singlet oxygen generated by a lipophilic photosensitizer in the lipid tail region (oil phase). These varied antioxidizing behaviors indicate that melatonin dwells at the headgroup subregion of the membranes. We anticipate that the methodology in this study can be widely utilized in the screening of antioxidants' spatial distribution and antioxidizing efficiency, and eventually in designing novel antioxidants that could deliver specific functions.

Clove oil has many functions such as antibacterial, anti-inflammatory, anti-oxidation. In this experiment, a self-emulsification method was used to prepare clove oil nanoemulsion. And then filter paper diffusion method, minimum inhibitory concentration, and minimum bactericidal concentration were used to study the inhibitory behavior of clove oil nanoemulsion on Escherichia coli and Staphylococcus aureus. And explore the antibacterial mechanism by dynamically testing the content of nucleic acid and protein in the culture solution during the antibacterial process. The results show that when the surfactant content is 10 wt%, the hydrophile-lipophile balance (HLB) is 13.93, and the oil phase content is 2 wt%, a clove oil nanoemulsion with better dispersion and smaller average particle size can be prepared. The minimum inhibitory concentration (MIC) of clove oil nanoemulsion against Escherichia coli and Staphylococcus aureus is 0.5, 0.25 mg/mL, and the minimum bactericidal concentration (MBC) is 1, 2 mg/mL. The increase in protein content and the exponential growth of nucleic acid release also indicated that the clove oil nanoemulsion destroys the integrity of the cell membrane. The experimental results can provide a reference for the application of clove oil nanoemulsion in food, medicine and other fields. GRAPHIC ABSTRACT: [Image: see text]

Porous polymerized high internal phase emulsion (polyHIPE) monoliths are synthesized by using Span 80 with different cosurfactants. The results reveal that the void size can be reduced by employing cosurfactants, except for Tween 20. Furthermore, the openness of polyHIPEs changes by using different cosurfactants or by varying their concentration. To further investigate the effect of cosurfactants, we perform rheology measurements on the interface of the aqueous and oil phase. This study demonstrates the important role of interfacial elasticity in the successful preparation of polyHIPEs with different morphologies. Additionally, this study suggests that the increase in interfacial elasticity hinders the formation of interconnections between pores, known as windows. Finally, the compression test is performed to investigate the effect of the pore structure on the mechanical properties.

Background The number of people who are aware of consuming healthy and natural foods are consistently increasing. Natural emulsifier-stabilized emulsions have attracted widespread attention in food industry. Ultrasound has a potentially wide range of applications in the preparation of food emulsions. Scope and approach This review briefly discussed the effects of ultrasound-assisted emulsification (UE) on emulsion formation along with introducing the different emulsifier stabilized emulsions. In special, the effects of UE on the emulsion properties such as viscosity, emulsifying properties, droplet size, zeta potential, emulsifier properties and oil phase properties have been summarized. Finally, the advantages and disadvantages of current studies on UE in food system were also discussed. Key findings and conclusions The review demonstrated that the process of UE may not be a simple process of breaking up droplets, but may be a more complicated process. UE can be used to prepare many emulsifier stabilized food emulsions such as protein, polysaccharide, protein-polysaccharide and protein-polysaccharide-surfactant. Proper UE treatment could improve the rheological properties and emulsifying properties, reduce the emulsion droplet size as well as increase the absolute zeta potential of emulsions. UE was shown to be a good method to unfold proteins and form good emulsions. However, the studies on sonication induced emulsifier properties were still limited. High-intensity ultrasound had no significant influence on the oil oxidation and oil profiles, whereas increased the anti-oxidative ability of some emulsions. Beside the large-scale ultrasonic devices should be developed, the effects of UE on emulsifier and oil phase during and after sonication should be further studied in the future.

Sea cucumbers are attractive marine natural sources as they are enriched with functional biomaterials that can contribute in accelerating wound healing. The present study was carried out to prepare cream formulations comprising extract of sea cucumber with different type of oil phase, namely F1 (olive oil), F2 (tea tree oil) and F3 (lemongrass oil) to assess the influence of the oil on the physicochemical properties and the wound healing efficacy of the creams. The formulated creams showed satisfactory physicochemical characteristics such as homogeneity, spreadability, rheology, pH, and showed no evidence of phase separation even when the creams were kept at extreme conditions. The ex vivorelease profile of sea cucumber extract from the formulated creams was determined by using a Franz diffusion cells. F3 demonstrated a constant and yield the highest release percentage of sea cucumber extract, followed by F2 and F1. Topical application of the formulated creams on the excision wound in rats showed a significant wound healing efficacy compared to the control group. Among the creams formulation, F1 demonstrated a significantly higher rate of wound closure compared to F2, F3, and positive control. The wound healing efficacy of the formulated creams were not dependent on the ability of the oils in promoting skin permeation for the release of sea cucumber extract. This study depicted that lemongrass oil acted as a good skin permeation enhancer for the release of sea cucumber extract while olive oil worked in a more synergistic manner with sea cucumber extract in promoting wound healing.

Dye-filled microcapsules are an attractive way to identify microscopic damage of materials by the naked eye. However, there are many disadvantages in traditional microcapsule-based self-reporting materials, such as a poor self-reporting effect. A new concept for the design of self-reporting microcapsules is presented here. Our work develops a novel kind of dual-compartmental microcapsule via Pickering emulsion photopolymerization, which can encapsulate two interacting species ("pro-dye" and "developer") separately in a single microcapsule. In our strategy, SiO2 microspheres encapsulating polyetheramine (PEA, developer) were first prepared and employed as a Pickering emulsifier to stabilize oil-in-water emulsions, in which the oil phase consisted of 2',7'-dichlorofluorescein (DCF, pro-dye) and a monomer. After the monomer polymerization, a dual-compartment microcapsule, which encapsulated the pro-dye in the core and the developer in the shell, was obtained. Upon the rupture of the microcapsule, the pro-dye and the developer were released simultaneously and reacted to yield a pronounced chromogenic response. Compared with traditional double-microcapsule systems, this dual-compartment microcapsule system demonstrated a more efficient and pronounced self-reporting effect. This is the first time that a double-encapsulation scheme involving the compartmentalized release of two interacting species within a single microcapsule has been demonstrated for self-reporting, which overcomes the tough problems of the uneven distribution of the traditional double-microcapsule systems.

During atomisation, modified agricultural spray formulations can produce less fine spray (for drift control) or reduce the overall droplet size distribution (for efficacy). Motivated by the technical literature concerning antifoaming agents, emulsions with and without solid particles were studied to examine their effect on atomisation. For emulsions, the effects of oil type, oil droplet diameter, surfactant, and presence of solid particles in the oil phase on the sprayed droplet size distribution were examined. Test formulations were compared with a standard commercial formulation and several commercial low-drift adjuvants. Results indicated that large oil droplets and the presence of solid particles reduced the number of fine droplets produced in multi-phase emulsions.

The high viscosity of heavy oil is a vital parameter that hinders the heavy oil recovery efficiency. Viscosifying aqueous viscosity and reducing oil phase viscosity are the guiding principles under...

The effect of oil-droplet diameter on lipid oxidation in O/W emulsions is unclear, and conflicting results have been reported. These conflictions may be due to different experimental conditions being used, such as the type of oil, the type of emulsifier, temperature, and the range of oil-droplet diameters tested. The method used to evaluate the oxidation could also have varied among studies. In O/W emulsions, oxygen dissolved in the aqueous phase is transferred to the oil phase through the oil-water interface and is consumed in the oil phase by oxidation. Therefore, the effect of the oil-droplet diameter on the lipid oxidation rate was evaluated by simultaneously solving the mass balance equations of oxygen and oil in the oil phase. The simulation showed that the oil-droplet diameter does not affect the lipid oxidation rate in O/W emulsions with oil-droplet diameters on the order of micrometers or less because the oxidation reaction itself is rate-limiting.

Most of the foundation liquids in the market need makeup removers for cleaning, while the excessive use of makeup removers might lead to skin barrier damage, which would further lead to many kinds of dermatosis, such as skin sensitivity, facial telangiectasia, rosacea, acne, as well as various cosmetic contact dermatitis. Inspired by the protective effect of fiber-rich diet on the intestinal mucosal mechanical barrier, a novel hemp/cellulose nanocrystals (CNCs)-based foundation liquid featuring easy-wiping property has been constructed, which will effectively solve the post-makeup skin cleaning problems. In this experiment, the formula of the foundation liquid can be obtained through hemp/CNCs instead of mineral oil and titanium oxide, which are considered to have undesirable local tolerance, sensitizing potential, and are environmental pollutants, to create a moisture barrier. Industrial hemp is a hot issue in cosmetic research, and a great quantity of discarded industrial hemp stalk is available to be used to produce hemp/CNCs through grinding and acidification. The graft technique is adapted to obtain hemp/CNCs-g-polylactic acid (PLA). By replacing the hydroxyl group on the side of hemp/CNCs, hemp/CNCs-g-PLA reduces the intermolecular hydrogen bonding, resulting in a higher dispersion in the oil phase. The hemp/CNCs-g-PLA has excellent performance in terms of biological compatibility, water resistance, and non-penetration into the skin. With basic features of a foundation liquid to alleviate discoloration, age spots, and skin roughness, the foundation liquid based on hemp/CNCs-g-PLA provides a novel characteristic of easy-wiping, which helps to avoid the damage to the skin barrier caused by excessive cleansing.

In this study, a piperazinyl-based emulsifier (EA/AMPA) was synthesized to prepare water-in-oil (W/O) high internal phase emulsions (HIPEs). Using kerosene as the oil phase, stable HIPEs with internal phase fractions of up to 98% were prepared. This enabled the EA/AMPA to have a high efficiency, as the HIPEs with a 90% internal phase fraction could be easily prepared with 0.1% of EA/AMPA. In addition, the formation of HIPEs was not affected by the addition of Na+. Because of the fact that EA/AMPA has a hydrophilic head with two tertiary amines, EA/AMPA could be easily recovered from the oil phase by adjusting the pH to acidic values. Moreover, the unique structure promoted the formation of stable HIPEs, even with crude oil used as the oil phase. The results indicate that EA/AMPA has the potential to significantly contribute to the preparation of W/O HIPEs and that the design of the hydrophilic head with two tertiary amines can provide a reference for the fabrication of new W/O emulsifiers.

Understanding the physical structure of greases can provide critical insight into improving the lubricating performance of a grease. Observation of the grease structure can be quite difficult depending on the type of grease and the length scale of the structure. Polyurea greases in previous reports have typically been examined by removal of the oil phase, which significantly changes the polyurea structure. This paper examines the effect of sample preparation conditions on the microstructure of polyurea greases. This study reveals new structures in the polyurea that have not been observed in the previous literature, including entangled fibers and nanotubes. Correlation is found between the observed polyurea microstructure coverage and grease stiffness.

Microscopic high aspect ratio particles have many applications including enhanced delivery of active ingredients and food stability. Here, we develop a simple, scalable process that produces particles with a continuously controllable aspect ratio. Oil-in-water emulsion droplets are quenched and crystallize in the presence of surfactants that facilitate the ejection of the solid oil phase from its liquid precursor. Tuning the ejection and crystallization rates to be comparable, by adjusting the surfactant concentration and quench depth, promotes anisotropic particle growth by continuously ejecting solidified oil from the precursor droplet as the crystallization proceeds. We predict the accessible morphologies using an analytical geometric model that indicates a nonconstant contact angle during the crystallization process. We see that the crystal aspect ratio is dependent on the surfactant concentration, which can be explained as a variation of the maximum growth angle achieved during crystallization.

Reduced fat mayonnaise is a mayonnaise that reduces some oil to reduced fat content, but reduced fat mayonnaise has a disavantages. A decrease in the oil phase which can affect the stability of the mayonnaise emulsion. One alternative is the addition of watermelon rind flour to increase the quality of mayonnaise. The purpose of this study was to determine the quality of mayonnaise with the addition of watermelon rind flour as stabilizer. The method used was experimental design using a completely randomized design. The treatment were the addition of watermelon rind flour as much as 2%, 4%, 6% and control as a comparison. Data were analyzed by analysis of variance and continued with UJBD. The results showed that the addition of watermelon rind flour gave highly significant effect on emulsion stability and moisture content, had a significant effect on pH and did not gave significant effect on sensory evaluation of mayonnaise. This study concluded that the addition of 6% watermelon rind flour as stabilizer produces good quality mayonnaise.

Asphaltene stability can be perturbed during the oil production and transportation, leading to asphaltene precipitation and deposition. Chemical inhibitors are usually added to the oil phase to pos...

The formation of spontaneous double emulsions is a peculiar phenomenon in emulsion systems. When compared to the traditional one-step and two-step methods for preparing double emulsions, spontaneous emulsification can not only steadily load uniform water droplets into an oil phase, but can also facilitate the preparation of emulsions with higher stability. However, the limited solubility of salts, which are typically used to modify osmotic pressure, in organic oils has inhibited the viability of this method for the preparation of W/O/W double emulsions. In this paper, a redox-driven spontaneous emulsification method is developed and investigated. Instead of employing oil-soluble salts, an oxidation reaction is implemented in the oil phase, which produces cation radicals and iodide counterions to generate osmotic pressure. Additionally, amphiphilic polymer chains are harnessed as stabilizers for the newly formed W/O interfaces. Various characterization methods have been used to elucidate the mechanism of both the oxidation reaction and the spontaneous formation of double emulsions.

There is a large debate on the destabilization mechanism of emulsions. We present a simple technique using mechanical compression to destabilize oil-in-water emulsions. Upon compression of the emulsion, the continuous aqueous phase is squeezed out, while the dispersed oil phase progressively deforms from circular to honeycomb-like shapes. The films that separate the oil droplets are observed to thin and break at a critical oil/water ratio, leading to coalescence events. Electrostatic interactions and local droplet rearrangements do not determine film rupture. Instead, the destabilization occurs like an avalanche propagating through the system, starting at areas where the film thickness is smallest., 16 pages, 5 figures

Alginate microspheres (AMs) have received much attention as a novel drug delivery system owing to various advantages of alginate such as inexpensiveness, nontoxicity, biocompatibility and biodegradability. The well-designed fabrication method is essential to achieve desired AMs suitable for specific drug delivery system. Reports on AMs preparation techniques have increased rapidly in the last decade. A number of synthesis parameters have been investigated for the improvement of physical, chemical and biological properties of AMs. Hence, this review summarizes the work to date on the fabrication techniques of AMs for drug delivery system, including spray-drying, extrusion and emulsification/gelation technique. Besides, the influence of various factors such as alginate concentration, oil phase, surfactant, cross-linker concentrations, cross-linking time, stirring speed, model drug and drug content on the morphologies, properties and encapsulation efficiency (EE) of AMs via extrusion and emulsification/gelation technique are summarized. Before embarking on the development of any drug delivery system, a thorough understanding of drug release mechanism and factors that impact the drug release profile are essential, which are also covered in this review.