凸棒颗粒稳定的橄榄油／水型Pickering乳状液的制备条件及形成机理研究

选取凹凸棒作为乳化剂,系统研究pH、颗粒浓度、油相体积分数以及不同价态盐对橄榄油／水型Pickering乳状液稳定性的影响,结果表明,体系pH在4～9范围内可制备出稳定的乳状液;颗粒浓度的提高可增强乳液的分层和聚结稳定性;乳液液滴直径随油相体积分数的增加先增大后减小;无机盐的引入不会对乳液相及水相的体积产生影响,但对乳液液滴的尺寸分布影响显著,其中NaCl浓度的增加有利于乳状液液滴数均直径的增加,而CaCl2浓度增加时,乳状液液滴数均直径呈现先增大后减小的变化趋势。研究表明,凹凸棒可作为一种新型纳米乳化剂应用于绿色乳状液的制备。     

Treatment of oil-in-water emulsions: performance of a sawdust bed filter

The effect of operating conditions on the performance of a sawdust bed filter used for the treatment of an oil-in-water emulsion was investigated. A metalworking fluid (3 vol.% oil) was used as oil-in-water emulsion and sawdust as filter medium and sorbent. Because of the high stability of the emulsion, small amounts of inorganic salt (calcium sulphate) were mixed with the sorbent, acting as coagulant to achieve the emulsion breakdown. The influence of flow rate, bed height, temperature and the amount of coagulant salt added was studied. Experimental results show that several processes are involved in oil removal from oil-in-water emulsions, i.e. coagulation, coalescence, adsorption or straining. More than 99% of oil content in the influent stream was removed. Experimental results show that low-cost sorbents like sawdust are feasible to be used in the treatment of oil-in-water emulsions if small amounts of coagulant salts are added to the filter media.     

驻波场原油破乳及盐衡算方法

原油在加工前要进行脱水脱盐处理。声波破乳是十分有效的强化原油脱水脱盐方法。利用声波的破乳机理．在驻波场中考察了声波声强和辐照时间等对鲁宁管输原油破乳的影响,并得到较好的试验条件为：原油预热温度约80℃,搅拌强度400r·min^-1,搅拌时间15min,破乳剂NS-2003用量20μg·g^-1,注水量5％,声波辐照时原油温度80℃。辐照声强0．38W·cm^2,辐照时间约5min,沉降温度75℃,沉降时间90min;在此实验条件下原油的脱后含水率0．37％．盐含量3．85mg·L^-1;脱水率92．696,脱盐率87．9％。原油盐衡算发现,原油注水量偏少时,脱后原油中盐含量偏高的原因是原油与水不能充分接触,盐不能充分地被洗脱。     

Formation and stability studies of multiple (w/o/w) emulsions prepared with newly synthesized rosin-based polymeric surfactants

The multiple (water-in-oil-in-water, w/o/w) emulsions were prepared using newly synthesized rosin-based polymeric surfactants. The oil phase used was liquid paraffin. These emulsions were evaluated for stability by various methods: conductivity, viscosity, particle size, and visual inspection. The stability studies were carried out at 37°C and 4°C for 1 month. The multiple emulsion prepared with polymer 7 was found to be more stable compared to the emulsions prepared with polymer 2.     

Formation and Stability Studies of Multiple (w/o/w) Emulsions Prepared with Newly Synthesized Rosin-Based Polymeric Surfactants

The multiple (water-in-oil-in-water, w/o/w) emulsions were prepared using newly synthesized rosin-based polymeric surfactants. The oil phase used was liquid paraffin. These emulsions were evaluated for stability by various methods: conductivity, viscosity, particle size, and visual inspection. The stability studies were carried out at 37°C and 4°C for 1 month. The multiple emulsion prepared with polymer 7 was found to be more stable compared to the emulsions prepared with polymer 2.     

Preparation and characterization of a submicron lipid emulsion of docetaxel: submicron lipid emulsion of docetaxel

Docetaxel, a widely used anticancer agent, has sparingly low aqueous solubility, thus Tween 80 and ethanol need to be added into its formulation, probably resulting in the toxic effects. In this study, we aimed to utilize submicron lipid emulsions as a carrier of docetaxel to avoid these potential toxic vehicles. Preformulation study was performed for rational emulsions formulation design, including drug solubility, distribution between oil and water, and degradation kinetics. Supersaturated submicron lipid emulsion of docetaxel was prepared by temperature elevation method. Soya oil and Miglyol 812 can incorporate docetaxel up to 1.0% (drug to lipid ratio) and were used as the oil phase of emulsions. The optimal formulation of docetaxel is composed of 10% oil phase, 1.2% soybean lecithin, 0.3% Pluoronic F68, and 0.4 or 0.8 mg/mL docetaxel, with particle size in the nanometer range, entrapment efficiency more than 90%, and is physicochemically stable at 4 and 25 degrees C for 6 months. Animal studies showed that docetaxel emulsion has significantly higher area under the curve (AUC) and C(max) in rats compared to its micellar solution. The results suggested that the submicron lipid emulsion is a promising intravenous carrier for docetaxel in place of its present commercially available docetaxel micellar solution with potential toxic effects.     

Insect tricks: two-phasic foot pad secretion prevents slipping

Many insects cling to vertical and inverted surfaces with pads that adhere by nanometre-thin films of liquid secretion. This fluid is an emulsion, consisting of watery droplets in an oily continuous phase. The detailed function of its two-phasic nature has remained unclear. Here we show that the pad emulsion provides a mechanism that prevents insects from slipping on smooth substrates. We discovered that it is possible to manipulate the adhesive secretion in vivo using smooth polyimide substrates that selectively absorb its watery component. While thick layers of polyimide spin-coated onto glass removed all visible hydrophilic droplets, thin coatings left the emulsion in its typical form. Force measurements of stick insect pads sliding on these substrates demonstrated that the reduction of the watery phase resulted in a significant decrease in friction forces. Artificial control pads made of polydimethylsiloxane showed no difference when tested on the same substrates, confirming that the effect is caused by the insects’ fluid-based adhesive system. Our findings suggest that insect adhesive pads use emulsions with non-Newtonian properties, which may have been optimized by natural selection. Emulsions as adhesive secretions combine the benefits of ‘wet’ adhesion and resistance against shear forces.     

Remediation of groundwater contaminated with DNAPLs by biodegradable oil emulsion

Emulsion-based remediation with biodegradable vegetable oils was investigated as an alternative technology for the treatment of subsurface DNAPLs (dense non-aqueous phase liquids) such as TCE (trichloroethylene) and PCE (perchloroethylene). Corn and olive oil emulsions obtained by homogenization at 8000rpm for 15min were used. The emulsion droplets prepared with corn and olive oil gave a similar size distribution (1-10microm) and almost all of initially injected oil, >90%, remained in a dispersed state. In batch experiments, 2% (v/v) oil emulsion could adsorb up to 11,000ppm of TCE or 18,000ppm of PCE without creating a free phase. Results of one-dimensional column flushing studies indicated that contaminants with high aqueous solubility could be efficiently removed by flushing with vegetable oil emulsions. Removal efficiencies exceeded 98% for TCE and PCE with both corn and olive oil emulsions. The results of this study show that flushing with biodegradable oil emulsion can be used for the remediation of groundwater contaminated by DNAPLs.     

Preparation and Characterization of a Submicron Lipid Emulsion of Docetaxel: Submicron Lipid Emulsion of Docetaxel

Docetaxel, a widely used anticancer agent, has sparingly low aqueous solubility, thus Tween 80 and ethanol need to be added into its formulation, probably resulting in the toxic effects. In this study, we aimed to utilize submicron lipid emulsions as a carrier of docetaxel to avoid these potential toxic vehicles. Preformulation study was performed for rational emulsions formulation design, including drug solubility, distribution between oil and water, and degradation kinetics. Supersaturated submicron lipid emulsion of docetaxel was prepared by temperature elevation method. Soya oil and Miglyol 812 can incorporate docetaxel up to 1.0% (drug to lipid ratio) and were used as the oil phase of emulsions. The optimal formulation of docetaxel is composed of 10% oil phase, 1.2% soybean lecithin, 0.3% Pluoronic F68, and 0.4 or 0.8 mg/mL docetaxel, with particle size in the nanometer range, entrapment efficiency more than 90%, and is physicochemically stable at 4 and 25°C for 6 months. Animal studies showed that docetaxel emulsion has significantly higher area under the curve (AUC) and C_max in rats compared to its micellar solution. The results suggested that the submicron lipid emulsion is a promising intravenous carrier for docetaxel in place of its present commercially available docetaxel micellar solution with potential toxic effects.     

NIR‐Triggered Photothermal Responsive Coatings with Remote and Localized Tunable Underwater Oil Adhesion

Tunable underwater oil adhesion is a critical issue in interfacial science and industrial applications. Although much progress has been made to date, development of novel smart coating materials that can selectively change the wetting property at different areas is considerably scarce. Here, a simple strategy is proposed to fabricate photothermal responsive coatings, which can change the oil adhesion behavior from low‐adhesive rolling state to high‐adhesive pinning state for a variety of oily liquids in a remote, local, and reversible manner. Owing to this unique controllability, the adhesion and no‐adhesion of oil droplets on the coated surfaces can be easily manipulated by remote and local near‐infrared radiation.     

Influences of combustion improver content and motionless time on the stability of two-phase emulsions

The heavy molecular bonds of liquid fuels can be broken with the assistance of a nitromethane fuel additive by virtue of its explosive and flammable properties to obtain greater heat release. Because of the immiscibility between nitromethane and petro-diesel, two-phase emulsions of nitromethane dispersed in the oil phase of a mixture of diesel and biodiesel were prepared. The experimental results show that microwave irradiation produced an emulsion with a larger number of dispersed nitromethane droplets in the continuous oil mixture, a smaller mean droplet size, and lower turbidity than magnetic stirring, and thus was a better method for preparation of the two-phase emulsion. The increase in the nitromethane weight fraction increased the number of dispersed nitromethane droplets and the emulsion turbidity. In addition, allowing the emulsion preparation to remain motionless for a longer period of time after either method resulted in an obvious reduction in the emulsification stability (ES).     

Delivery Systems for Low Molecular Weight Payloads: Core/Shell Capsules with Composite Coacervate/Polyurea Membranes

Composite polyurea/coacervate core/shell capsules are formed by coupling associative biopolymer phase separation with interfacial polymerization. They combine the excellent chemical stability of synthetic polymer barriers with the strong adhesive properties of protein‐based complex coacervates, inspired by biological underwater glues. To encapsulate volatile oil droplets, a primary coacervate hydrogel capsule is formed by a protein and weak polyanion and is reinforced with a polyurea membrane synthesized in situ at the interface between the coacervate and the oil core. The polyurea layer provides an excellent permeability barrier against diffusion of small volatile molecules while the coacervate portion of the shell enhances adhesion on the targeted substrate.     

Drying oil-in-water Pickering emulsions to make redispersible powders

We report on the formation of powder by drying oil-in-water emulsions stabilized by silanised silica nanoparticles. Drying was achieved by spraying fine droplets (up to a hundred micrometres in diameter) of the emulsions into a chamber of hot, flowing air. We show that the surfaces of droplets of the emulsions become enriched with nanoparticles as the water evaporates in the drying chamber. Controlling the relative amounts of oil and particles in the droplets being dried is the key to encapsulating the oil drops within the powder. Dried Pickering emulsions containing up to 40 wt% encapsulated oil that could be dispersed in water as drops of the same size as in the original emulsion were produced.     

Dynamically Reconfigurable,Multifunctional Emulsions with Controllable Structure and Movement

Dynamically reconfigurable oil‐in‐water (o/w) Pickering emulsions are developed, wherein the assembly of particles (i.e., platinum‐on‐carbon and iron‐on‐carbon particles) can be actively controlled by adjusting interfacial tensions. A balanced adsorption of particles and surfactants at the o/w interface allows for the creation of inhomogeneity of the particle distribution on the emulsion surface. Complex Pickering emulsions with highly controllable and reconfigurable morphologies are produced in a single step by exploiting the temperature‐sensitive miscibility of hydrocarbon and fluorocarbon liquids. Dynamic adsorption/desorption of (polymer) surfactants afford both shape and configuration transitions of multiple Pickering emulsions and encapsulated core/shell structured can be transformed into a Janus configuration. Finally, to demonstrate the intrinsic catalytic or magnetic properties of the particles provided by carbon bound Pt and Fe nanoparticles, two different systems are investigated. Specifically, the creation of a bimetallic microcapsule with controlled payload release and precise modulation of translational and rotational motions of magnetic emulsions are demonstrated, suggesting potential applications for sensing and smart payload delivery.     

Tuning Surface Wettability and Adhesivity of a Nitrogen‐Doped Graphene Foam after Water Vapor Treatment for Efficient Oil Removal

An environment‐friendly water vapor treatment for realizing a highly hydrophobic (contact angle ≈147.5°) and oleophilic N‐doped graphene foam (NGF) for efficiently removing oil from oil/water emulsions is presented. 3D porous networks of NGF with high N content are prepared by subjecting a mixture of graphene oxide and 5 vol% pyrrole to a hydrothermal process; the mixture is then freeze‐dried and annealed under a N₂ atmosphere. The surface wettability and adhesivity are tuned through water vapor treatment by forming a low‐surface‐energy hydrocarbon layer, with no chemical modification. The effectiveness of the hydrophobic/oleophilic NGF in removing oil from an oil/water emulsion is demonstrated.     

SiO2/聚合物纳米复合乳液的合成研究进展

从合成SiO2/聚合物纳米复合乳液的常用SiO2原料、合成机理和制备方法等方面综述了国内外最新的研究进展,最后介绍了SiO2/聚合物纳米复合乳液在涂料、粘接剂、塑料改性等领域的应用,并对今后的研究重点和发展方向作了展望。     

PARTICLE COUNTING OIL AND WATER EMULSIONS

Because of their speed and convenience, optical particle counters are widely used for particle size analysis of liquid samples. In some cases, both solid particles and emulsified water or oil may be present in a sample. Since emulsion droplets are counted as if they are solid particles, analysis and data interpretation for these samples are difficult. Until recently, no suitable method existed for distinguishing solid contaminants from emulsion droplets. This paper discusses a method which overcomes this limitation. Through the use of a surfactant-laden nonpolar dilution fluid, water is incorporated into reverse micelles too small to be seen by most optical particle counters. As a result, only solid contaminants are counted, and many problems associated with the analysis of emulsions are overcome. Results obtained from a wide range of oil and water emulsions are used to evaluate the merits and possible applications of the new technique.     

高分子乳化剂在丙烯酸酯乳液共聚物中的应用

用丙烯酰胺系列高分子乳化剂和小分子乳化剂分别制备了丙烯酸酯共聚物乳液。本文同时也对比了两种乳化剂对乳液基本物理的影响。     

An inexpensive route to prepare mesoporous hollow silica microspheres using W/O ethanol/edible soybean oil macroemulsion as the template

Mesoporous hollow silica microspheres were prepared by using W/O emulsion consisting of ethanol droplets as a template in edible soybean oil. Ethanol droplets containing ammonia solution were generated by employing ultrasonication in pure soybean oil. The droplets were colloidally stabilized by means of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). Later on, another proportion of soybean oil dissolving tetraethyl orthosilicate (TEOS) was added to the W/O emulsion. The sol-gel reaction of TEOS was achieved only at the interface of the emulsion droplets, resulting in hollow silica microspheres. After washing the resultant with acetone, mesoporous hollow silica microspheres were simply obtained. Throughout this liquid template-based process, mesoporous hollow silica microspheres can be inexpensively synthesized without employing solid templates.     

PARTICLE COUNTING OIL AND WATER EMULSIONS

ABSTRACT

Because of their speed and convenience, optical particle counters are widely used for particle size analysis of liquid samples. In some cases, both solid particles and emulsified water or oil may be present in a sample. Since emulsion droplets are counted as if they are solid particles, analysis and data interpretation for these samples are difficult. Until recently, no suitable method existed for distinguishing solid contaminants from emulsion droplets. This paper discusses a method which overcomes this limitation. Through the use of a surfactant-laden nonpolar dilution fluid, water is incorporated into reverse micelles too small to be seen by most optical particle counters. As a result, only solid contaminants are counted, and many problems associated with the analysis of emulsions are overcome. Results obtained from a wide range of oil and water emulsions are used to evaluate the merits and possible applications of the new technique.