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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.

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.

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...

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.

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.

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.

A novel experimental procedure was proposed to investigate the phase behavior of a solvent mixture (SM) (64 mol% CH4, 8 mol% CO2, and 28 mol% C3H8) with heavy oil. Then, a theoretical methodology was employed to estimate the phase behavior of the heavy oil–solvent mixture (HO–SM) systems with various mole fractions of SM. The experimental results show that as the mole fraction of SM increases, the saturation pressures and swelling factors of the HO–SM systems considerably increase, and the viscosities and densities of the HO–SM systems decrease. The heavy oil is upgraded in situ via asphaltene precipitation and SM dissolution. Therefore, the solvent-enriched oil phase at the top layer of reservoirs can easily be produced from the reservoir. The aforementioned results indicate that the SM has promising application potential for enhanced heavy oil recovery via solvent-based processes. The theoretical methodology can accurately predict the saturation pressures, swelling factors, and densities of HO–SM systems with various mole fractions of SM, with average error percentages of 1.77% for saturation pressures, 0.07% for swelling factors, and 0.07% for densities.

The nucleation and growth of liquid droplets on solid substrates have received much attention because of the significant relevance of these multiphase processes to both nature and practical applications. There have been extensive studies on the condensation of water from the air phase on solid substrates. Here, we focus on water diffusion through the oil phase and subsequent settlement on solid substrates because such interfacial droplets are formed. Voronoi diagram analysis is proposed to statistically characterize the size distribution of the growing droplets. It is found that modification of the standard Voronoi diagram is required for systems of interfacial droplets which have a noncircular shape and/or whose centers change with time. The modified Voronoi analysis of the growing droplets provides an automatic quantification of the droplet distribution and reveals that (i) during the nucleation stage, the interfacial droplets do not nucleate at the same time because the nucleation of newly formed droplets competes with the growth of the existing ones; (ii) the growth of interfacial droplets comes from water diffusion from the bulk water layer, and/or from adjacent interfacial droplets, and/or from coalescence of interfacial droplets; and (iii) the sizes of interfacial droplets become more polydispersed on P-glass but more monodispersed on OTS-glass as time goes. This work opens a new perspective on the formation of interfacial droplets at the interface between oil and the solid substrate and demonstrates the capability of an automatic analysis method, which can be potentially applied to similar interfacial multiphase systems.

In order to study the microscopic oil displacement mechanism of polymeric surfactant in chemical cold flooding for heavy oil, the indoor microscopic visualization displacement experiments were carried out. The flooding experiment of heavy oil was conducted by using water, osmotic modified oil displacing agent (a kind of polymeric surfactant) and water-in-oil emulsion (obtained by mixing polymeric surfactant and heavy oil) as displacing phases to study the mechanism of polymeric surfactant to enhance oil recovery in heavy oil reservoir. The experimental results show that the polymeric surfactant can increase the viscosity of the water phase, reduce the water-oil mobility ratio, expand the swept area, and there is no obvious fingering phenomenon which occurs during water flooding. The polymeric surfactant has the surfactant characteristics which can reduce the interfacial tension between oil and water to promote the formation of oil droplets with smaller droplet diameter. And the interfacial film composed of polymeric surfactant molecules will be formed on the surface of oil droplets to prevent the coalescence of oil droplets and improve the flow ability of oil phase. The water-in-oil emulsion can be miscible with the oil in heavy oil displacement process, and thus sweeps the areas such as the dead pores which cannot be swept by water and polymeric surfactant flooding, which increases the sweep efficiency to a certain extent. Cited as : Xu, F., Chen, Q., Ma, M., Wang, Y., Yu, F., Li, J. Displacement mechanism of polymeric surfactant in chemical cold flooding for heavy oil based on microscopic visualization experiments. Advances in Geo-Energy Research, 2020, 4(1): 77-85, doi: 10.26804/ager.2020.01.07

In this paper, the organic nano-sepiolite was modified to obtain highly dispersibility in the oil phase, and then, EVA (ethylene-vinyl acetate)/nano-sepiolite was prepared by melt blending. The eff...

To deal with the demulsification of O/W emulsions, a novel kind of core–shell structural amphiphilic soft matter, HPEI-g-Cn (n = 10, 12, 14, 16, 18), with hyperbranched polyethyleneimine (HPEI) as the core and fatty acid chain Cn as the shell, is designed and synthesized. With the existence of amphiphilic HPEI-g-Cn, O/W emulsions can be thoroughly separated into two phases with a clear oil–water interface to reach demulsification equilibrium within 40 min. The oil removal ratio can exceed 99.9% under the addition of 40 ppm in simulative emulsions, and simultaneously the water content in the oil phase is less than 0.01%. This demulsifier can also contribute to excellent separation efficiency (up to 99.9%) for O/W emulsions from two China's oilfields, and even for heavy oil emulsions. More importantly, it is noted that the HPEI-g-Cn demulsifiers after demulsification are evenly and tightly dispersed at the oil–water interface as shown by wide-angle X-ray scattering (WAXS) and cryo-electron microscopy (cryo-EM), which is beneficial to the subsequent recovery and utilization. With eco-friendly characteristics, outstanding demulsification performance and promising recyclability, the amphiphilic macromolecules HPEI-g-Cn as special soft matter display great promise to achieve industrial applications in the future.

The behavior of run-and-tumble nanoswimmers which can self-propel in two immiscible liquids such as water–oil systems and are able to cross the interface is investigated by dissipative particle dynamics. At the steady-state, the partition ratio (φ) of nanoswimmers between the two immiscible liquids is obtained, and it depends on the active force (Fa), run time (τ), and swimmer–solvent interactions. The partition ratio φ is found to grow generally with increasing Fa2τ. At sufficiently large Fa, it is surprising to find that hydrophilic nanoswimmers prefer to stay in the oil phase rather than in the water phase. The partition ratio is also influenced by the hydrophobicity of swimmers in the oil phase. Two simple models are proposed to describe the partition ratio, including a near-equilibrium model and a kinetic model. Surface accumulation appearing at an impenetrable interface is also observed at the fluid–fluid interface for small Fa but it vanishes for sufficiently large Fa.

This study aims to develop a new formulation of a sauce by incorporation of air in the oil phase. First, the effect of mono- and diglyceride (MDG) concentration (2, 6, and 10 wt.%), whipping speed (1100, 3200, and 5400 rpm) and time (up to 60 min) on foam properties were studied. The desired foam (overrun ≥ 60%) achieved by oil containing 10 wt.% MDG at 3200 rpm for 10 min. Optical micrographs showed stable air bubbles (20–25 μm) even after six months of storage. Then this foam was used to produce an aerated reduced-fat sauce. For purposes of comparison, aerated sauce, along with commercial full- and reduced-fat sauces, was analyzed by measuring the rheological properties, stability, and color. The power-law equation was used to model the behavioral features (R2 = 0.99). Compared with the full-fat sauce, the consistency coefficient (K) of aerated and reduced-fat sauces was more close to each other, and their flow behavior index (n) was higher. Overall samples showed shear-thinning thixotropic flow behavior. Also, aerated sauce showed acceptable stability and lightness (L*). These findings affirm the potential of nonaqueous foam for the production of reduced-fat sauces, which could be meet consumers’ and marketing requirements.

An algorithm for quantitative analysis of the process of separation of a substance in a batch-operated centrifuge is developed based on the scientific postulates of the theory of interpermeating and interacting heterogeneous fluid systems (by the example of water-oil emulsion). The results of analytical and numerical investigations of the process of separation of the oil phase from the water-oil emulsion are presented.

The full potential of triplet fusion photon upconversion (TF-UC) of providing high-energy photons locally with low-energy excitation is limited in biomedicine and life sciences by its oxygen sensitivity. This hampers the applicability of TF-UC systems in sensors, imaging, optogenetics and drug release. Despite the advances in improving the oxygen tolerability of TF-UC systems, the evaluation of oxygen tolerability is based on comparing the performance at completely deoxygenated (0% oxygen) and ambient (20-21%) conditions, leaving the physiological oxygen levels (0.3-13.5%) neglected. This oversight is not deliberate and is only the result of the lack of simple and predictable methods to obtain and maintain these physiological oxygen levels in an optical setup. Herein, we demonstrate the use of microfluidic chips made of oxygen depleting materials to study the oxygen tolerability of four different micellar nanocarriers made of FDA-approved materials with various oxygen scavenging capabilities by screening their TF-UC performance over physiological oxygen levels. All nanocarriers were capable of efficient TF-UC even in ambient conditions. However, utilizing oxygen scavengers in the oil phase of the nanocarrier improves the oxygen tolerability considerably. For example, at the mean tumour oxygen level (1.4%), nanocarriers made of surfactants and oil phase both capable of oxygen scavenging retained remarkably 80% of their TF-UC emission. This microfluidic concept enables faster, simpler and more realistic evaluation of, not only TF-UC, but any micro or nanoscale oxygen-sensitive system and facilitates their development and implementation in biomedical and life science applications. publishedVersion

Oleosomes are a micron sized mass of oil droplets enclosed by a specific membrane of protein-phospholipid mixtures typically found in plants and microorganisms to serve as an energy reserve for potential needs. Interest in plant-derived oleosomes in the food industry has recently grown significantly, as these unique natural emulsions are made of unrefined natural oil phase. In a similar way, there is also significant interest in converting liquid oil emulsions into soft solid oleogel structures through physical trapping with water-soluble biopolymers. Natural oleosome suspensions were stabilized with xanthan and pectin hydrocolloids and converted for the first time in this study into oleosome templated oleogel structures. 1–1.5% of hydrocolloid was sufficient to encapsulate oleosomes when electrostatic deposition was used and upon drying a soft solid structure was obtained. Oleosomes coated with xanthan gum resulted in oleogels structures with higher firmness and elastic modulus values compared pectin coated samples. These findings provided novel information in designing the gels structures composed of unrefined, natural oil in the form of oleosomes.

Oil/water (O/W) emulsion droplets coated with soyasaponin (Ssa) were used as emulsifiers to prepare emulsions with hierarchical configurations (2.82 μm). Ssa is a natural triterpenoid with amphiphilic properties and an excellent emulsifying activity. Stable O/W emulsions were prepared and characterized using an ultrasonic method at a Ssa concentration of 2.5 wt%. The resultant hierarchical emulsions were further prepared using O/W droplets as emulsifiers. It was observed that the stability of the hierarchical emulsions changed with alterations to the ratio of O/W droplets to the oil phase. As the number of droplets increased, the more the surface area of the hierarchical emulsion was covered. Additional observations included a decreased particle size, increased negative charge and viscoelastic behavior, and enhanced emulsion stability. The emulsion was most stable when the O/W droplet addition was 29%. The addition of O/W droplets continued to increase, and there was an imbalance in the ratio of O/W droplets to the oil phase; the excess O/W droplets induced instability in the emulsion, resulting in a degradation of the emulsion quality. We monitored hierarchical emulsions with different concentrations of emulsifiers for 30 days, and the results indicated that hierarchical emulsions could meet the demand for long-term storage. This provides a new theoretical basis for the construction and application of complex emulsion systems.

Droplet interface bilayers (DIBs) mimic the cell membrane and provide a model membrane platform for studying basic biophysical processes. This paper demonstrates a pressure-driven microfluidic system for the rapid and automated generation of alternating DIB networks, each comprised of four aqueous nanoliter droplets. The microfluidic device features five inlets, one for the continuous oil phase and four independent aqueous channels for T-junction droplet generation. Droplet production rates are controlled by adjusting the applied pressure of each inlet; therefore, controlling the pattern of droplets produced in the main channel and further stored in a downstream hydrodynamic trapping array. Each trap is designed to capture and hold in place one row of four droplets, forming three interfacial lipid bilayers per network. The potential for greater combinations of droplets in a network enables an increased complexity necessary for performing parallel multiplexed biological assays. We further examined flow behavior in response to changes in resistance of the microfluidic device when using a pressure driven source. This microfluidic system provides a high-throughput method for generating DIB networks of complex droplet patterning.

Water‐in‐oil‐in‐water (W/O/W) double emulsions present a reduced‐fat alternative to conventional O/W food emulsions, as part of the dispersed oil phase is replaced with water. In this study, the concept of a reduced‐fat whipped topping produced by W/O/W technology was proven. Whipping of a W/O/W emulsion, containing only 20% oil phase and a solid fat content of 78%, produced a superior whipped topping, in terms of firmness and overrun, compared to its whipped O/W emulsion counterparts. The presence of PGPR in the oil phase increased structure formation during whipping, while the additional dispersed‐phase volume resulted in a better air inclusion. Two commercial monoacylglycerols (saturated and unsaturated) were investigated to improve the whipping properties of the produced W/O/W double emulsion. Both increased the susceptibility towards partial coalescence, thereby reducing whipping time and overrun, while increasing firmness of the produced whipped topping. Furthermore, the effect was stronger for the unsaturated than for the saturated monoacylglycerol.

Lavender essential oil (LO) is widely used as a bioactive component in cosmetics. In this study, the pseudo ternary phase diagrams of microemulsions composed of oil phase (LO: short-chain a...

Many oil-encapsulation techniques, in which particles are used to improve the stability of polyunsaturated fatty acids (PUFAs) against oxidation and the handling of oils, have been reported. We developed techniques for encapsulating oil within powders with a liquid–liquid interfacial crystallization by using nozzleless electrostatic atomization. This process was used to prepare fine spherical encapsulated soybean oil particles with a microscale single process. An inexpensive soybean oil containing PUFAs was chosen as the oil phase. W/O emulsion systems were synthesized via the electrostatic atomization process. After the W/O emulsions were prepared, glycine and taurine well provided in supplements were used as the wall material for encapsulation. The soybean oil content of the encapsulated particles and their stability at high temperatures were evaluated. The oxidative stability of the soybean oil during high-temperature storage was improved for the encapsulation.

The emulsions with nano-sized dispersed phase is called nanoemulsions having a wide variety of applications ranging from food, dairy, pharmaceutics to paint and oil industries. As one of the high energy consumer methods, ultrasonic emulsification (UE) are being utilized in many processes providing unique benefits and advantages. In the present review, ultrasonic nano-emulsification is critically reviewed and assessed by focusing on the main parameters such pre-emulsion processes, multi-frequency or multi-step irradiations and also surfactant-free parameters. Furthermore, categorizing aposematic data of experimental researches such as frequency, irradiation power and time, oil phase and surfactant concentration and also droplet size and stability duration are analyzed and conceded in tables being beneficial to indicate uncovered fields. It is believed that the UE with optimized parameters and stimulated conditions is a developing method with various advantages.

Low porosity silica microcapsules (SiO2/Sodium monofluorophosphate) were synthesised by a soft-template method in room temperature. Morphology of silica microcapsule can be controled by changing the concentration of TEOS in reinforcement phase in the range of 1%–4%. With the increased concentration, thickness of capsule raised and some rod-like structures occured. The impacts of oil phase volume fraction and rotation speed of emulsification on the diameter distribution of capsules were discussed. The former functioned via changing viscosity of mixed solution while the latter played a complicated role in diameter distribution. This method of microencapsulation used in our paper is easy to achieve for that the experimental conditions are mild and do not require complicated or costly instruments, which is suitable for industrial production. In addition, we also explored the changes of microcapsules under different environmental factors including temerature and pH.

We present numerical and experimental investigation on the existence of diffusion-induced compositional variations in a reservoir fluid in the absence of convective mixing. New pressure-decay experimental data are presented for ethane in contact with stock tank oil, and the values of diffusivity and solubility parameters are obtained by using the one-dimensional transient diffusion model and integral-based regression method. We show the variation in oil composition through composition-height measurements at the end of the experiment. Finally, the diffusion model with estimated parameters is used to predict the compositional variations, where comparisons show excellent agreement with the measurements, validating the parameter estimation technique and quantifying the compositional variations in the oil phase caused by diffusion.

Emulsified water droplets must be extracted from crude oil for economical and transport purposes, which is achievable by chemical demulsification. Four different chemicals were tested on water-in-crude oil emulsions using a newly developed nuclear magnetic resonance (NMR) method. Droplet size distributions were mapped at the beginning and end of experimentation. In addition, slice selections (soft radio-frequency (RF) pulses) were used to isolate the signal from residual droplets within the separated oil phase to study coalescence patterns in the emulsion bulk. The NMR could also return rapid continuous brine profiles for analysis of sedimentation rates and free water appearance kinetics. The residual water content was isolated by strong bipolar gradient suppression, thereby allowing focus on the smaller droplets still emulsified in the top region in the brine profiles. Optimum concentrations were found for each chemical, and blends of several chemical demulsifiers were noticeably more efficient than the single-component demulsifiers in this study.

Here, we report the first example of one-pot fabrication of tubular polymer nanofibers (TPFs) by a hyper crosslinking reaction in confined droplets. The self-polycondensation of monomers was carried out in a newly developed dual oil phase system. The difficulty in the preparation of polymers with a regular morphology was overcome by self-polycondensation.

Today emulsion preparation is receiving a lot of scientific attention, since emulsions are playing an essential role in many of the big industries, such as food, pharmaceutical or cosmetic industry. One of the most promising techniques for emulsion preparation is ultrasound emulsification. The purpose of this study is to expand the knowledge on the ultrasonically assisted emulsification model, that has not been amended since 1978. The model explains that oil-in-water emulsion formation is a two-step process. Firstly, the surface of the oil phase is disturbed and separated by the acoustic waves. Secondly, cavitation implosions further disrupt and disperse oil drops. We have used a high-speed camera to closely observe oil-in-water emulsion formation. The images show, that the ultrasound emulsification process is profoundly more complex. While the first and the last step of emulsion formation are the same as believed until now, additional intermediate stages of water-in-oil and even oil-in-water-in-oil occur.

The monodispersity of giant unilamellar vesicles (GUVs) is important in terms of the quantitative analysis and experimental reproducibility as biomimetic microreactors. Here, we report a facile and reproducible microfluidics-based method to generate monodisperse thin-walled water-in-oil-in-water (W/O/W) droplets as a precursor of GUVs. We explored the composition of liquids and membranes for the stable transfer of monodisperse water-in-oil (W/O) droplets across the W-O laminar flow interface, and determined the condition in which W/O/W droplets with ~1 µm shell thickness are produced at 100% efficiency. We observed the dewetting phenomenon of the oil phase, which is necessary to convert the lipid-stabilized W/O/W droplets to GUVs.

Oil-in-water (O/W) emulsions with 10%, 20%, 30% and 40% oil were prepared using soybean protein isolate (SI) 1, 2 and 3% as stabilizer. Viscosity of emulsions was determined. Microscope observation of all emulsions immediately after preparation was performed. Correlation among viscosity, emulsion droplet size and percents of oil phase were found. Emulsions prepared with high percent oil exhibit smaller average droplet size and greater stability.

Nanoemulsions are a class of two-phase liquid systems with an internal phase droplet size of less than 200 nm. Although two-phase emulsion systems have been known for decades, the concept of nanoemulsions is fairly recent. Nanoemulsion stability is far more reliable than traditional two-phase “macro”-emulsion systems, which has led to nanoemulsions becoming an attractive option for the delivery of diverse categories of lipophilic small molecule drugs and bioactive agents. This chapter presents an overview of the theories underlying the formulation of emulsions for maximum stability and potential for scale-up. Both low and high energy dispersive techniques have been discussed with suggestions of suitable equipment. Various techniques for formulation have been discussed with specific attention to the nature of the drug and suitability of the excipients. Correlations have been established between stability of nanoemulsions and the nature and concentration of the surfactant, cosurfactant, oil phase, and temperature. A brief section has been devoted to the in vitro characterization of nanoemulsions with reference to instrumentation and techniques used in the pharmaceutical industry. The last part of the chapter is devoted to the application of nanoemulsions in anticancer drug delivery, with examples on how these novel delivery systems can enhance the efficacy of anticancer drugs while significantly reducing the toxic effects of the chemotherapeutic agents.

Summary To understand how the recovery factor decreases in porous media through the trapping of hydrocarbons, it is necessary to be able to predict the capillary pressure in pore-scale networks. The capillary pressure is determined by the shape of the fluid interfaces, which strongly depends on the wettability of the pore walls and on the pore structure itself. We use the Surface Evolver to simulate the shapes of fluid interfaces when gas enters a one end of a channel, representing a model porous medium, containing a liquid phase (oil). We determine the shape of the interface between the two fluids (oil and gas) to give accurate measurements of the capillary pressure pc in porous media. By making small changes in the fluid volumes, we predict in a quasi-static manner the variation of capillary pressure during the process of oil mobilization by gas invasion. We consider a channel with an equilateral triangular and rectangular cross-section. Increasing the contact angle (θ) at which the wetting fluid (oil phase) meets the walls causes the capillary pressure to decrease until it reaches zero at a critical contact angle. The capillary pressure increases as the liquid phase is removed.

For phase change characteristics of air foam flooding in Changing ultra-low permeability reservoirs, using the PVT high pressure physical device, gas chromatograph, studies were injected into the air and the gas-phase oxidation of P-X diagram under reservoir conditions, Phase Behavior of crude oil and air bubbles after numerous contacts. Combined with PVT simulation software and the phase equilibrium model, calculate the critical temperature 424.4 °C and critical pressure 9.85 MPa of crude oil. Results show that: under the same pressure, gas dissolved in crude oil after oxidation is strong in the air. Because the foam system and crude oil emulsification during contact has produced multiple contact oxidation, the effect is less than the air and oil, resulting from oxidation of C2-C6 is relatively small, while the C7-C16 is relatively more, gas phase composition to move closer to the C2-C6 trend is relatively slow, and the oil phase group causes the increase of C7-C16 content has to move closer to the C7+, the occurrence of mixed phase difficulty is air contact many times greater, for the study of miscible flooding, non miscible flooding mechanism and gas injection project design provides important basis.

Emulsions are thermodynamically unstable systems, since they will separate to reduce the interfacial area between the oil phase and the water phase, as a function of time. As a metastable system, surfactant molecules, amphiphilic polymers or solid particles must be present before a stable emulsion system is formed. These components of an emulsion system are called emulsifiers. The relative balance of the hydrophilic and lipophilic properties of these emulsifiers is known to be the most important parameter dictating the emulsion type, whether an oil-in-water (o/w) or water-in-oil (w/o) emulsion. Irrespective of the emulsion type formed, demulsification is a costly exercise in the oil and gas industry. This chapter describes the fundamental role played by surface active agents (surfactants) as integral components of a chemical demulsifier.

Shell scientists are making the most of advancing imaging technology to reveal what happens in a 3D porous medium during emulsification.

In the recent decade, injection of nanoparticles (NPs) into underground formation as liquid nanodispersions has been suggested as a smart alternative for conventional methods in tertiary oil recovery projects from mature oil reservoirs. Such reservoirs, however, are strong candidates for carbon geo-sequestration (CGS) projects, and the presence of nanoparticles (NPs) after nanofluid-flooding can add more complexity to carbon geo-storage projects. Despite studies investigating CO2 injection and nanofluid-flooding for EOR projects, no information was reported about the potential synergistic effects of CO2 and NPs on enhanced oil recovery (EOR) and CGS concerning the interfacial tension (γ) of CO2-oil system. This study thus extensively investigates the effect of silica NPs on the γ of CO2/decane system at elevated pressure and temperature to recognise the potential impact of NPs-injection on the future CGS projects. To achieve this, a wide-ranging series of tests have been conducted to reveal the role of hydrophilic and hydrophobic silica NPs on γ of the CO2/oil system. n-decane was utilized as model oil and different amounts of NPs were mixed with the oil phase. Oil-NPs dispersions were formulated using an ultrasonic homogenizer. The γ of the CO2/oil system was measured at different pressures (0.1 to 20 MPa) and temperatures (25 to 70 °C) using a high-pressure temperature optical cell. The γ data were measured using the pendant drop technique via axisymmetric drop shape analysis (ADSA). The results showed that, generally, CO2/oil γ subjected mainly to pressure, temperature, and with less extent to NPs load in the oil phase. γ decreases with increased pressure until reaching a plateau where no more significant decrease in γ was observed. The γ trend with increased temperature, on the other hand, was more completed. No significant impact of temperature on γ was recorded with low pressure (≤ 5 MPa). Similarly, at relatively high pressure (≥ 25 MPa), only a slight variation of IFT with temperature change was recorded. However, for the pressure range from 5 – 25 MPa, IFT was increased remarkably with temperature. Furthermore, NPs in the oil phase exhibit a remarkable influence on IFT. In this context, the presence of hydrophilic silica NPs in the oil phase can significantly reduce the γ of the CO2/decane system. However, hydrophobic silica NPs showed less influence on IFT reduction. The outcomes of this work afford good understandings into applications of NP for EOR and CGS applications and help to de-risk CO2-geological storage projects.

Microfluidic chips have demonstrated unparalleled abilities in droplet generation, including precise control over droplet size and monodispersity. And yet, their rather complicated microfabrication process and operation can be a barrier for inexperienced researchers, which hinders microdroplets from unleashing their potential in broader fields of research. Here, we attempt to remove this barrier by developing an integrated and modular revolving needle emulsion generator (RNEG) to achieve high-throughput production of uniformly sized droplets in an off-chip manner. The RNEG works by driving a revolving needle to pinch the dispersed phase in a minicentrifuge tube. The system is constructed using modular components without involving any microfabrication, thereby enabling user-friendly operation. The RNEG is capable of producing microdroplets of various liquids with diameters ranging from tens to hundreds of micrometres. We further examine the principle of operation using numerical simulations and establish a simple model to predict the droplet size. Moreover, by integrating curing and centrifugation processes, the RNEG can produce hydrogel microparticles and transfer them from an oil phase into a water phase. Using this ability, we demonstrate the encapsulation and culture of single yeast cells within hydrogel microparticles. We envisage that the RNEG can become a versatile and powerful tool for high-throughput production of emulsions to facilitate diverse biological and chemical research.

Microchannel (MC) emulsification for the preparation of monodisperse oil-in-water (O/W) and water-in-oil-in-water (W/O/W) emulsions containing palm oil as the oil phase was investigated for application as basic material solid/semi-solid lipid microspheres for delivery carriers of nutrients and drugs. Emulsification was characterized by direct observation of droplet generation under various operation conditions, as such, the effects of type and concentration of emulsifiers, emulsification temperature, MC structure, and flow rate of to-be-dispersed phase on droplet generation via MC were investigated. Sodium caseinate (SC) was confirmed as the most suitable emulsifier among the examined emulsifiers, and monodisperse O/W and W/O/W emulsions stabilized by it were successfully obtained with 20 to 40 &micro, m mean diameter (dm) using different types of MCs.

International audience; A hydrogel can be formed by an organogelator in the presence of a nanoemulsion. It is expected that this is due to a gelation transfer from oil to water. The system started with an oil-in-water nanoemulsion prepared according to a phase inversion temperature (PIT) process. Into this nanoemulsion consisting of Kolliphor® RH40 and Brij® L4 as surfactants, and Miglyol® 812 as oil and water, we introduced the organogelator 12-hydroxyoctadecanoic acid (12-HOA) in the oil phase. After cooling at room temperature, a slow reversible gelation of the water phase occurred with persistence of the nanoemulsion. This thermally reversible system was investigated using various techniques (rheology, turbidimetry, optical and electron microscopies, scattering techniques). Successive stages appeared during the cooling process after the nanoemulsion formation, corresponding to the migration and self-assembly of the organogelator from the oil nanodroplets to the water phase. According to our measurements and the known self-assembly of 12-HOA, a mechanism explaining the formation of the gelled nanoemulsion is proposed.

In-situemulsification of injected brines of various types is gaining increased attention for the purpose of enhanced oil recovery. The present experimental study aims at evaluating the impact of injecting various solutions of Na2CO3and MgSO4 at different flow rates resembling those in the reservoir and near wellbore using a glass micromodel with different permeability regions. Emulsification process was visualized through the injection of deionized water and different brines at different flow rates. The experimental results showed that the extent of emulsions produced in the vicinity of the micromodel exit was profoundly higher than those at the entrance of the micromodel. The injection of Na2CO3brine after deionized water caused the impact of emulsification process more efficiently for attaining higher oil recovery than that for the MgSO4brine. For instance, the injection of MgSO4solution after water flooding increased oil recovery only up to 1%, while the equivalent figure for Na2CO3was 28%. It was also found that lower flow rate of injection would cause the displacement front to be broadened since the injected fluid had more time to interact with the oil phase. Finally, lower injection flow rate reduced the viscous force of the displacing fluid which led to lesser occurrence of viscous fingering phenomenon.

Chia seed oil-candelilla wax (3 g/100 g) oleogel was prepared and subjected to annealing at three different temperatures (30, 35 and 40 °C). Light microscopy images showed the presence of needle-like crystals structures dispersed in the oil phase. Annealing disrupted the crystalline structures by reducing their number. Wide-angle X-ray dispersion analysis showed that the annealed oleogels did not inherit the pristine candelilla wax crystallinity. Small-angle X-ray dispersion analysis showed that the needle-like structures were transformed into platelets after annealing. The storage G′ and loss G″ moduli values were boosted after annealing, indicating that the annealing process induced a strong reorganization of the oleogel structure. FTIR analysis indicated that unsaturated ester groups from candelilla wax and chia seed oil can act as surfactants that, in combination with platelet structures from n-alkanes, reconfigure the structure of oleogels during the annealing process. Overall, the results showed that annealing is a suitable process for oleogel strengthening when wax contents are relatively low.

Surfaces with uniform and stable superwetting behavior have enormous application prospects. In particular, an air-water/oil amphibious superhydrophilic-superhydrophobic surface is advantageous in oil-water separation and oil-repellent materials. However, existing methods to create this property require either water pretreatment or time-consuming stimulation process, which makes instant oil-water identification impossible. Here, inspired by Namib desert beetle, we propose a strategy to construct layers differing in surface free energies to achieve surfaces that are simultaneously superhydrophilic-superoleophobic. Rough microcrystalline cellulose particles were modified by 2,2,6,6-tetramethyl-1-piperidinyloxy and perfluorooctanoic acid to successively construct high- and low-surface free energy layers. Surfaces prepared by simple spraying of these particles display excellent and stable superhydrophilicity-superoleophobicity under the amphibious conditions of air and water/oil, as well as excellent temperature and abrasion resistance. Pressed cotton membranes treated with these particles can effectively separate oil-water mixtures and oil-in-water emulsions without any pretreatment, even when the oil phase is highly viscous. Moreover, cotton gloves coated with these particles have superior water permeability and oil repellency without losing breathability. These results suggest a new approach towards oil-water separation and oil-repellent fabrics.