共查询到20条相似文献,搜索用时 31 毫秒
1.
H. Hasinovic 《Journal of Dispersion Science and Technology》2013,34(5):679-683
Some factors in the preparation of triple Janus emulsions in a single-step bulk process were investigated using optical microscopy. The emulsions consisted of water, O.097 weight fraction, a commercial surfactant, Tween 80, 0.03 weight fraction, a vegetable oil (VO), 0.18 weight fraction, and a silicone oil (SO), 0.72 weight fraction. A surprising connection was found between the state of the compounds prior to mixing and the final morphology as well as stability of the emulsion. Separately adding the compounds or with the surfactant dissolved in the vegetable oil, prior to mixing, did not result in a Janus emulsion. Instead, simpler emulsions with limited stability were attained even with prolonged mixing. Storing the compounds together without mixing for two days followed by mixing resulted in a Janus emulsion in which the (VO + SO)/W/VO drops were more sparsely populated with Janus drops, and emulsion stability was limited. Finally, preparing the emulsion from the aqueous surfactant solution and the two oils gave a (VO + SO)/W/VO/SO emulsion with the W drops heavily populated by Janus drops and with improved stability. 相似文献
2.
Shengwen Zou Quanxing Gao Zhen Tong 《Journal of Dispersion Science and Technology》2013,34(2):173-181
A series of W/O/W or O/W/O emulsion stabilized solely by two different types of solid nanoparticles were prepared by a two-step method. We explored the option of particular emulsifiers for the multiple Pickering emulsions, and a variety of nanoparticles (silica, iron oxide, and clay) only differing in their wettability was used. The primary W/O emulsion was obtained by the hydrophobic nanoparticles, and then the hydrophilic nanoparticles were used as emulsifier in the secondary emulsification to prepare the W/O/W emulsion. In a similar way, the primary O/W emulsion of the O/W/O emulsion was stabilized by the hydrophilic nanoparticles, while the secondary emulsification to prepare the O/W/O emulsion was effected with the hydrophobic nanoparticles. The resultant multiple Pickering emulsion was stable to coalescence for more than 3 months, except the W/O/W emulsions of which the secondary emulsion stabilized by clay nanoparticles became a simple O/W emulsion in a day after preparation. Moreover, the temperature and pH sensitive poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAm-co-MAA)) microgels were introduced as an emulsifier for the secondary emulsification to obtain the stimulus-responsive multiple W/O/W emulsion. Such microgel-stabilized multiple emulsions could realize the efficient controlled release of water-soluble dye, Rhodamine B (RB) on demand in a multiple-emulsion delivery system. 相似文献
3.
A vertical sleeve separator using glass microfiber with a mean diameter of 4 µm as coalescence medium was explored to remove oil from the oil-in-water (O/W) emulsions. The artificial emulsions were prepared by mixing diesel oil and water to obtain oil droplets with a mean diameter about 7 µm. A series of experiments were performed to investigate the effect of such parameters as bed porosity (0.850–0.925), bed height (2.0–20.0 mm), flow velocity (1.0–20.0 mL/s), and influent oil concentration (200.0–3000.0 mg/L) on the effluent oil concentration and oil removal efficiency. The obtained effluent oil concentration was from 4.98 to 53.04 mg/L, and the oil removal efficiency was 96.4–99.8%. In addition, the article identifies the interaction between bed porosity and height, explains the mutual influences between the emulsion velocity and concentration, and quantitatively derives the appropriate ranges of bed characteristics and operating conditions. 相似文献
4.
I. Masalova E. Kharatyan A. Ya. Malkin 《Journal of Dispersion Science and Technology》2013,34(8):1074-1078
The role of multi-wall carbon nanotubes (MWCNT) as a solid surfactant in highly concentrated water-in-oil emulsions was investigated. MWCNT were dispersed in the oil phase. These suspensions are viscoplastic fluids with the yield stress increasing by more than 1000 times with addition of 2% MWCNT, which demonstrates intensive “structurizing” ability. After emulsion preparation, MWCNT were concentrated at the interface, stabilizing emulsions. The dependence of the inversion point on MWCNT concentration was found. Emulsions containing up to 94 wt% of the aqueous phase can be prepared only when MWCNT is combined with conventional surfactant. Rheological properties of such compositions were measured. It was established that emulsions stabilized by a combined surfactant were more stable in comparison to conventional surfactant stabilized emulsion. 相似文献
5.
Mohsen Radi 《Journal of Dispersion Science and Technology》2013,34(4):582-589
In this study, it was aimed to compare the rheological properties of carboxymethylcellulose (CMC) in aqueous solutions and their corresponding emulsions containing 0.05, 0.1, 0.25, and 0.5% CMC in the aqueous phase. Samples with 0.05 and 0.1% CMC showed Newtonian behavior, but shear-thinning behavior was observed in CMC solutions and emulsions with increasing CMC concentrations to 0.25% and 0.5%. Rheological behavior of all samples were modeled by Power law (R 2 = 0.986–197) and Casson models (R 2 = 0.968–1). According to the Ostwald–de Waele model, the consistency index of all samples was increased and the flow behavior index decreased with increasing CMC concentration. Comparison of our data with four predicting models (Einstein, Larson, Pal, and Dougherty-Krieger equations) showed that the viscosity of continuous phase controls the viscosity of emulsions with high CMC concentrations and these models are not applicable for such situations. Addition of CMC increased the emulsion stability of O/W emulsions. This stability was increased with increasing CMC concentrations. 相似文献
6.
Rami A. Abdel-Rahem Faisal A. Al-Odail 《Journal of Dispersion Science and Technology》2014,35(7):1009-1017
The influence of synergistic interaction between sodium dodecylsulfate (SDS) and N,N-dimethyldodecan-1-amine oxide (DDAO) on their adsorption at air/water and solid/water interfaces at 20°C is investigated. The critical micelle concentration values obtained from surface tension measurements indicated strong synergism between SDS and DDAO, according to regular solution model. The excess surface concentration (Γ) and the minimum occupied area by single and mixed surfactant monomers (Amin) at liquid/air interface were also calculated. The adsorption onto the activated charcoal and silica was then measured to find out the correlation between surfactant synergism and their adsorption at solid/water interface. The amounts of surfactant adsorbed onto 1 wt% activated charcoal follow the trend: SDS/DDAO > DDAO > SDS. SDS molecules do not adsorb onto 5 wt% silica substrate, while SDS/DDAO mixed system was found to have the highest adsorption behavior. The obtained indicate that SDS can be removed from water by mixing it with amphoteric surfactant. 相似文献
7.
Tian Maozhang Song Xinmin Ma Desheng Wang Qiang Zhang Qun Wenli Luo 《Journal of Dispersion Science and Technology》2016,37(5):706-714
Transition from oil-in-water (O/W) emulsions to water-in-oil (W/O) emulsions and its action on enhanced oil recovery was investigated by viscosity, morphology, and simulated flooding experiments. This transition can be realized by increasing the volume ratio of oil to water or decreasing the emulsifier concentration. At a mass concentration of 0.3 wt%, the self-developed emulsifier FJ-1 mainly forms O/W emulsions at a volume ratio (oil to water) of 1:1. The emulsions behave as O/W emulsions with a low viscosity when the volume ratio of oil to water is below 2:1. Above 2:1, increasing volume ratio leads to the O/W emulsions transferring into W/O emulsions with high viscosity. For example, at a volume fraction of 4:1, the viscosity of W/O emulsions reaches 229.1 mPa · s, and separated water can hardly be detected. Transition from O/W emulsions to W/O emulsions with high viscosity can also be realized by decreasing the concentration of emulsifier to 0.05 wt% or lower at a volume ratio of 1:1. These may be the critical factors leading to transition from O/W emulsions to W/O emulsions at core conditions. Simulated flooding experiments show that emulsifier fluids can act as an in situ mobility improver and make an improvement of oil recovery even by 20.4%. The results indicate that the water-in-crude-oil emulsions possess great potential in enhancing oil recovery. 相似文献
8.
Benjarat Tepsongkroh Pitchaon Maisuthisakul Withida Chantrapornchai 《Journal of Dispersion Science and Technology》2013,34(8):1126-1133
The influence of polyglycerol polyricinoleate (PGPR) and biopolymers (gelatin and sodium alginate) on the stabilization of water-in-oil (W/O) emulsions was investigated to improve the encapsulation efficiency (EE) of water-in-oil-in-water (W/O/W) emulsions containing mango seed kernel extract (MSKE). The physical properties and EE of the emulsions were found to depend more strongly on PGPR than on biopolymers. High EE values of MSKE were obtained when W/O emulsions stabilized by 4–8 wt% PGPR were incorporated with 1–5 wt% gelatin, or by 6–8 wt% PGPR incorporated with 0.5–1.5 wt% sodium alginate in the inner aqueous phase. 相似文献
9.
Many industrial applications of oil-in-water emulsions involve salts containing ions of different valence. The properties of the oil-water interface (e.g., interfacial tension, zeta potential and interfacial shear viscosity) are strongly influenced by the presence of these salts. This work investigates the role of NaCl, CaCl2 and AlCl3 on these properties of the hexane-water interface in presence of a cationic surfactant, viz., hexadecyltrimethylammonium bromide. Addition of salt enhanced the adsorption of surfactant molecules at the hexane-water interface, which increased the interfacial charge density, and consequently, the zeta potential. Interfacial shear viscosity significantly decreased in the presence of salt. The effectiveness of salt at a given concentration was in the sequence: AlCl3 > CaCl2 > NaCl. The hexane-in-water emulsions coarsened with time due to the coalescence of hexane droplets. The increase in droplet size with time was analyzed by a model based on the frequency of rupture of the thin aqueous film. The rate constants for coalescence were determined. The rate of coalescence increased in presence of salt. 相似文献
10.
Malek Bendjaballah Rabah Oumeddour 《Journal of Dispersion Science and Technology》2013,34(9):1260-1272
To find an optimal formulation of oil-in-water (O/W) emulsions (φo = 0.05), the effect of emulsifier nature and concentration, agitation speed, emulsifying time, storage temperature and their mutual interactions on the properties and behavior of these dispersions is evaluated by means of an experimental design (Nemrodw software). Long-term emulsion stability is monitored by multiple light scattering (Turbiscan ags) and acoustic attenuation spectroscopy (Ultrasizer). After matching surfactant HLB and oil required HLB, a model giving the Sauter diameter as a function of emulsifier concentration, agitation speed and emulsification time is proposed. The highest stability of C12E4-stabilized O/W emulsions is observed with 1% emulsifier. 相似文献
11.
J. H. Lee 《Journal of Dispersion Science and Technology》2013,34(3):326-333
Cinnamoyl alginate microspheres were prepared using the water droplets of W/O emulsions as a template. Cinnamoyl alginates having variable content of the cinnamoyl group were prepared by a condensation reaction. The photo-dimerization degree of the cinnamoyl group increased as the molar ratio of pyranose unit/cinnamoyl group increased from 1:0.043 to 1:0.18. The air/water interfacial activity of cinnamoyl alginate also increased with increasing the molar ratio. Aqueous solution of cinnamoyl alginate was dispersed in mineral oil to obtain W/O emulsion. UV light (254 nm, 6 W) was irradiated to the emulsion to dimerize the cinnamoyl groups, and CaCl2 was added to the emulsion to cross-link the cinnamoyl alginate. The surface of UV-treated microspheres was rougher than that of UV-untreated microspheres, possibly due to the photo-dimerization-induced tension on the alginate chains. The release degrees for 24 hours of fluorescein isothiocyanate-dextran (FITC-dextran; MW 4000) from UV-treated microspheres were markedly higher than those from UV-untreated ones. This is possibly due to the intramolecular dimerization of cinnamoyl group. The UV irradiation-induced percentage increase in the maximum release degree was greater as the content of cinnamoyl group was higher. 相似文献
12.
The hydrophile-lipophile property of the sucrose monododecanoate changes from hydrophilic to lipophilic by adding an alcohol as a cosurfactant. With the addition of a short-alkyl-chain alcohol (pentanol, hexanol), the surfactant forms the middle-phase microemulsion whereas a lamellar liquid crystal (L!) appears with a medium- or long-chain alcohol (heptanol, octanol, decanol) at the balanced state in water/ SE/ cosurfactant/ decane system. The effect of changing oil was also studied in the presence of a middle-chain cosurfactant (heptanol). A short-chain aromatic oil (m-xylene) forms middle-phase microemulsion whereas a longer aliphatic one (hexadecane) forms lamellar liquid crystalline phase in a dilute region when the HLB of surfactant is balanced in a given system. O/W emulsions become stable on the hydrophilic-surfactant-rich side whereas W/O emulsions are stable on the cosurfactant-rich side. Emulsions are very unstable in the three-phase regions. However, when the lamellar phase is produced, emulsions become stable at the balanced state because water and oil are incorporated in L! phase in the longer cosurfactant systems such as water/ SE/ octanol/ decane and water/ SE/ decanol/ decane. 相似文献
13.
M. Yu. Koroleva V. A. Shcherbakov L. Kh. Khasanova A. I. Rakitin S. A. Shirokikh E. V. Yurtov 《Colloid Journal》2018,80(3):272-281
The porosity of polymer materials produced by polymerizing dispersion media of highly concentrated emulsions may be predicted, provided that the emulsions are stable. The study of the stability of water-in-oil (W/O) emulsions containing styrene as a dispersion medium at 25 and 65°C has shown that emulsions with a dispersed phase fraction of 0.75 and sorbitan monooleate concentrations of 1.5–20.0 vol % are stable to coalescence but are unstable to sedimentation. Emulsions with a dispersed phase fraction of 0.95 are stable to both coalescence and sedimentation at sorbitan monooleate concentrations of 10–20 vol %. Open-pore polymer materials are formed from emulsions with dispersed phase fractions of 0.75 and 0.95 at sorbitan monooleate concentrations of 2.0–3.5 and 10–12 vol %, respectively. At a dispersed phase fraction of 0.75 and a sorbitan monooleate concentration of <2 vol %, a multiple O/W/O emulsion is formed, the polymerization of which yields a porous polymer material containing spherical polystyrene particles inside pores. At higher surfactant concentrations in emulsions with dispersed phase fractions of 0.75 and 0.95 partly destroyed porous materials are formed. 相似文献
14.
Gilsane G. Morais Wanderley P. Oliveira Pedro A. da Rocha-Filho 《Journal of Dispersion Science and Technology》2014,35(11):1551-1556
The process parameters are important in the development of emulsions containing liquid crystals. Thus, we studied the influence of the mixing speed in microscopic and rheological features. Oil-in-water emulsions using vegetable oils and nonionic surfactant were developed employing gradual raise of the mixing speed. It decreased the liquid crystal formation and the density values, and increased apparent viscosity values. The most suitable mixing speed was 600 rpm, since it allowed the attainment of emulsion with better performance and presence of lamellar liquid crystals. However, all emulsions were stable in these experimental conditions and presented pseudoplastic behavior and tixotropy. 相似文献
15.
Mohammad Bagher Sadeghi Vahid Taghikhani Cyrus Ghotbi 《Journal of Dispersion Science and Technology》2013,34(3):356-368
Rheological behavior of two crude oils and their surfactant-stabilized emulsions with initial droplet sizes ranging from 0.5 to 75 µm were investigated at various temperatures under steady and dynamic shear testing conditions. In order to evaluate the morphology and Stability of emulsions, microscopic analysis was carried out over three months and average diameter and size distribution of dispersed droplets were determined. The water content and surfactant concentration ranged from 10 to 60% vol/vol and 0.1 to 10% wt/vol, respectively. The results indicated that the rheological properties and the physical structure and stability of emulsions were significantly influenced by the water content and surfactant concentration. The crude oils behaved as Newtonian fluids over a wide range of shear rates, whereas the emulsions behaved as non-Newtonian fluids, indicating shear-thinning effects over the entire range of shear rates. The viscosity, storage modulus and degree of elasticity were found to be significantly increased with the increase in water content and surfactant concentration. The maximum viscosity was observed at the point close to the phase inversion point where the emulsion system changes from water-in-oil emulsion to oil-in-water emulsion. The results also indicated that the rheological properties of crude oils and their emulsions are significantly temperature-dependent. 相似文献
16.
Byeong-Gyu Park In-Ji Park Jong-Sub Han Sang-Min Lee Chon-Gu Lee 《Journal of Dispersion Science and Technology》2013,34(4):560-565
There have been few studies on the factors that determine the overall appearance of emulsions. Optical properties are quite important in determining the perceived quality of emulsion-based products. The overall appearance of an emulsion is determined by the way that it interacts with electromagnetic radiation in the visible region of the spectrum, for example, reflection, transmission, adsorption, and scattering. These interactions are principally determined by the characteristics of emulsion droplets (size, concentration, and refractive index). The present study aims at characterizing the optical properties and rheological behaviors of water-in-oil emulsions, especially macroemulsions. There is a decrease in the absorbance spectra as increasing glycerin ratio in aqueous phase because the difference of refractive index between oil phase and aqueous phase decreased, which improved the transparency of water-in-oil emulsion. The absorbance of linear and branched surfactant emulsions were smaller than that of alkyl modified branched surfactant emulsion. Moreover the transparency of emulsions prepared with linear and branched surfactants was much clearer than that of alkyl modified branched surfactant emulsion. The absorbance spectra also showed that low polar oil attributed to the more transparent emulsion, compared with high polar or nonpolar oil. However, these kinds of oils were not helpful to prepare transparent emulsion because the appearance of these emulsions was translucent or opaque, even if polyols in aqueous phase was 30 wt%. 相似文献
17.
纳米SiO2与阳离子表面活性剂的相互作用及其诱导的正辛烷-水乳状液的双重相转变 总被引:1,自引:0,他引:1
研究了3种不同结构的水溶性阳离子表面活性剂对纳米二氧化硅颗粒的原位表面活性化作用, 它们分别是单头单尾的十六烷基三甲基溴化铵(CTAB)、单头双尾的双十二烷基二甲基溴化铵(di-C12DMAB)和双头双尾的Gemini型阳离子三亚甲基-二(十四酰氧乙基溴化铵)(II-14-3), 并通过测定Zeta电位、吸附等温线及接触角等参数对相关机理进行了阐述. 结果表明, 阳离子表面活性剂吸附到颗粒/水界面形成以疏水基朝向水的单分子层, 从而增强了颗粒表面的疏水性是原位表面活性化的基础. 通过吸附CTAB和II-14-3, 颗粒的疏水性适当增强, 能吸附到正辛烷/水界面稳定O/W(1)型乳状液; 而通过吸附di-C12DMAB所形成的单分子层更加致密, 颗粒的疏水性进一步增强, 进而使乳状液从O/W(1)型转变为W/O型; 当表面活性剂浓度较高时, 由于链-链相互作用, 表面活性剂分子将在颗粒/水界面形成双层吸附, 使颗粒表面变得亲水而失去活性, 但此时体系中游离表面活性剂的浓度已增加到足以单独稳定O/W(2)型乳状液的程度. 因此当采用纳米二氧化硅和di-C12DMAB的混合物作乳化剂时, 通过增加di-C12DMAB的浓度即可诱导乳状液发生O/W(1)→W/O→O/W(2)双重相转变. 相似文献
18.
Virangkumar N. Lad 《Journal of Dispersion Science and Technology》2013,34(1):78-83
Oil-in-water (O/W) emulsions are widely used in the preparation of many cosmetics, foods, and pharmaceutical products. Microstructure and stability of such emulsions are of utmost importance for their acceptability by the end user. In the present work, we studied the O/W emulsions to know the effects of two bio-derived additives—juice of Coriander sativam L., and milk of Cocos nucifera L, which have good nutrient value for their use in food emulsions. Addition of Cocos nucifera L. milk resulted in enhanced stability with decrease in the polydispersity of dispersed droplets in the emulsions due to the presence of proteins in it. Addition of Coriander sativam L. provided better stability against pH variation from 4 to 8. 相似文献
19.
Ju Hyup Lee 《Journal of Dispersion Science and Technology》2014,35(12):1801-1808
Cinnamoyl Pluronic F127 (CP F127) was prepared by reacting cinnamoyl chloride and Pluronic F127. On the 1H NMR spectrum of CP F127, 1.2 moiety of cinnamoyl group was found to be attached to one molecule of CP F127. Using pyrene as a fluorescence probe, it was found that not only Pluronic F127 but also CP F127 could be readily assembled into micelles, and the critical micelle concentration was around 0.015 mg/ml and 0.03 mg/ml, respectively. Pluronic F127 in aqueous solution (2% w/v) could form no particles in 10–20°C, but particles (ca. 30 nm in diameter) were detected on a dynamic light scattering machine in 25–40°C possibly due to the thermal micellization. However, CP F127 was assembled into particles (ca. 230 nm) even in the lower temperature range, possibly because of the intermolecular hydrophobic interaction of the cinnamoyl group. The particle size of CP F127 strongly depended on the medium temperature and UV irradiation time. CP F127 was a good emulsifier for the preparation of O/W emulsions. The oil droplet size markedly increased upon UV irradiation (254 nm, 6 W), possibly because of the photo-dimerization of cinnamoyl group, but it was little affected by the temperature change (10–40°C). 相似文献
20.
Haihua Pei Jijiang Ge Mingchao Ma Lei Zhang Yueliang Liu 《Journal of Dispersion Science and Technology》2013,34(11):1548-1556
Severe viscous fingering during water flooding of heavy oil leaves a large amount of oil untouched in the reservoir. Improving sweep efficiency is vital for enhancing heavy oil recovery. This study presented a laboratory study for improving sweep efficiency by alkaline flooding in heavy oil Reservoirs. This included glass-etched micromodel flooding tests, one-dimensional flooding experiments and three-dimensional physical model study. The micromodel tests show that W/O droplet flow plays a prominent role in the alkaline flooding to improve sweep efficiency. There is a minimum alkaline concentration that generates the W/O droplet flow, and the W/O droplet flow is more obvious with the alkaline concentration increasing. A series of flood tests were conducted using 325 mPa · s, 2000 mPa · s, and 3950 mPa · s heavy oils to assess the effectiveness of W/O droplet flow in alkaline flooding for enhanced heavy oil recovery. The flood tests results demonstrate the considerable potential for improved heavy oil recovery by alkaline flooding, and moreover, the incremental oil recovery has been found to increase as the alkaline concentration increases. The result obtained in three-dimensional physical model study indicates that the sweep area can be greatly improved by the formation of W/O droplet flow in alkaline flooding. 相似文献