十六烷基三甲基溴化铵/正丁醇/正辛烷/水油包水型微乳体系的相行为

文中分别考察了助表面活性剂(正丁醇)、有机溶剂(正辛烷)、温度、钨酸钠溶液浓度对十六烷基三甲基溴化铵(CTAB)/正丁醇/正辛烷/水油包水(W/O)型微乳区域形成的影响,并对该微乳体系的结构进行了电导研究,确定了微乳液体系形成区域及最佳比例配方。研究表明:助表面活性剂、有机溶剂、盐溶液质量浓度对该微乳液体系的微乳区域都会产生影响,温度对该微乳区域几乎没有影响;且当CTAB/正丁醇质量比为1∶2,(CTAB+正丁醇)/正辛烷质量比为4∶6时(滴加蒸馏水前),能够得到较大且稳定的微乳区域。该研究从热力学相图原理上为纳米粒子可控制备提供了理论依据。     

硅油/水纳米乳液的制备技术研究

以聚二甲基硅油为油相物质,非离子表面活性剂为乳化剂,采用相转变温度(PIT)法制备了硅油/水纳米乳液。通过研究硅油/乳化剂/水体系的拟三元相图,确定了纳米乳液的原料配比,并对优化配方体系制得的硅油/水纳米乳液样品进行表征。结果表明,在配方组成(w/%)为:脂肪醇聚氧乙烯醚乳化剂5,聚二甲基硅油5,余量为水的条件下,制备的纳米乳液的乳化粒子粒径在165 nm左右,其Zeta电位为-0.95 mV,乳化粒子呈球形。     

三唑磷纳米乳液制剂

通过拟三元相图法研究不同表面活性剂和三唑磷混合体系的相行为,筛选出制备三唑磷纳米乳液制剂的合适表面活性剂S1(聚氧乙烯醚类)和S2(硫酸盐);确定了S1和S2的最佳配比为7:1(摩尔比).考察了三唑磷和表面活性剂S2对表面活性剂S1浊点的影响,通过动态光散射实验测定不同配方在不同稀释倍数时乳液粒径的大小.确定三唑磷纳米乳液制剂的最佳配方为三唑磷质量分数25%,表面活性剂75%S(S1与S2摩尔比7:1),该配方加水稀释到800倍时仍是稳定透明的纳米乳液.     

反相微乳液法制备纳米氧化铁颗粒的结构及性能

测定了多种表面活性剂构成的反相微乳液体系对于水及盐溶液的载量,找到了一种具有较高氯化铁溶液载量的反相微乳液体系Egepalco-520/环己烷(或石油醚PE)/H2O.利用该体系制备纳米氧化铁的粒径与形态和盐溶液的浓度、加入量及表面活性剂/油的比有关.在表面活性剂/油比较高时,可以制备出粒径小于10 nm的氧化铁,但所制备的氧化体的结晶性较差.     

SDS/正丁醇/正庚烷/水微乳液稳定性分析及应用

研究了十二烷基硫酸钠(SDS)/正丁醇/正庚烷/水(或氯化镁与硝酸铝混合水溶液或氢氧化钠溶液)四组分形成稳定微乳液的条件。考察了表面活性剂与助表面活性剂的质量比、温度、pH值、盐浓度对该体系稳定性的影响及水与表面活性剂的摩尔比(ωo)对水核粒径的影响。结果表明,m(SDS)∶m(正丁醇)=4∶6时,反相微乳液最稳定,对温度变化不敏感,pH值为7～13时,具有较好的稳定性,随着镁铝混合盐溶液浓度的增加,反相微乳区域急剧缩小,水核粒径随着ωo增大而增大,在稳定微乳液区域内制备了分布较均匀,尺寸范围30～70 nm的粒状纳米颗粒。     

基于相图法的W/O型微乳液体系稳定性分析

以辛基苯基聚氧乙烯醚(TX-10)、十二烷基磺酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)为表面活性剂,以正戊醇、正己醇和正庚醇为助表面活性剂,以正戊烷为油相,制备了油包水型(W/O)微乳液.用相图法分析了微乳液体系的热力学稳定性,计算了水核半径的大小,并考察了影响微乳液W/O区域范围的各种因素.结果表明:这几种微乳液体系在实验条件下能自发形成:微乳液的水核半径处于纳米量级,可作为制备纳米粒子的超微反应器;以TX-10为表面活性剂时,水核可以包容更多的水分子,微乳液的W/O区域较大;而以CTAB为表面活性剂时,由于其极性头之间的空间和静电排斥作用强,微乳液的W/O区域最小;以硝酸镧溶液作为分散相时,微乳液的W/O区域变化较小;随着温度的升高,微乳液的W/O区域显著减小.     

W/O微乳液技术与纳米粒子的控制合成

分析了W／O微乳液的形成机理、结构特征以及用W／O微乳液法合成纳米粒子的基本原理。讨论了制备条件如水与表面活性剂的比值,反应物、表面活性剂、助表面活性剂的浓度以及焙烧条件对纳米粒子特征的影响。指出应该加强对纳米粒子生成反应动力学的研究,加强微乳液法与其它纳米粒子制备技术的耦合研究,并注意改善非极性溶剂和表面活性剂的回收率以降低制备成本。     

微乳液法制备BaF_2纳米粉体

采用CTAB/正戊醇/正辛烷/水反相微乳液体系,制备了BaF2纳米粉体.研究了微乳液体系中(水与表面活性剂的摩尔比)对BaF2尺寸和形貌的影响.用扫描电子显微镜、X射线衍射仪表征样品的形貌和结构.结果表明:所得产物粒径为80nm～800nm.     

采用不同方法合成CuS纳米粒子研究

分别采用水热合成法及微乳液法制备了纳米CuS粒子。以醋酸铜和升华硫为原料配成稳定溶液,进行水热合成得到纳米CuS粒子;以表面活性剂十六烷基三甲基溴化铵(CTAB)、有机溶剂正庚烷、水和助表面活性剂正丁醇组成的W/O型微乳体系,在加热状态下合成纳米CuS粒子。并采用UV-VIS、XRD和TEM等分析手段对粉体进行了表征。     

纳米氧化铈的制备及其反相微乳液的稳定条件

探讨了用于制备氧化铈纳米粒子的反相微乳体系组成及稳定性,以溴化十六烷基三甲基铵/正丁醇/环己烷/水构成了用于制备纳米氧化铈的W/O微乳液,通过测定体系的电导率的方法确定相点,绘制了溴化十六烷基三甲基铵和正丁醇-环己烷-水反相微乳区拟三元相图.结果表明,表面活性剂与助表面活性剂质量比,即溴化十六烷基三甲基铵与正丁醇的质量比等于1.6时为制备纳米粒子的最佳值,加入硝酸铈会使微乳液的区域减小,随着温度的升高微乳区域略微减小.按实验确定的条件,制备出纳米氧化铈,XRD分析结果表明,纳米氧化铈粒径为19~22 nm.     

Technological Aspects of Nanoemulsion Formation of Low‐Fat Foods Enriched with Vitamin E by High‐Pressure Homogenization

Formation of a low‐fat oil‐in‐water (O/W) nanoemulsion enriched with vitamin E using the nonionic surfactant Tween 40 is studied by means of a high‐pressure homogenizer. The effect of different process variables of the emulsification process, including pressure, temperature, and concentration of the emulsifying agent, is evaluated. The relation between pressure and the obtained mean droplet diameter is derived and described by an equation which can be taken as a basis of any process design. The droplet size can be decreased by increasing the vitamin E concentration. A higher fat content slightly affects the droplet size distribution and the mean droplet diameter of the nanoemulsion, so it is recommended to use preparations of nanoemulsions with low fat contents enriched with vitamin E for dietary supplement.     

Development of Nanoemulsion of Silicone Oil and Pine Oil Using Binary Surfactant System for Textile Finishing

Nanoemulsions of silicone oil and pine oil using a binary surfactant system were prepared. Silicone oil and pine oil were used to achieve softness and mosquito repellency and antibacterial activity respectively when the nanoemulsion was applied on the fabric. A silicone surfactant (AG-pt) and a hydrocarbon surfactant (TDA-6) were used in different proportions to obtain stable nanoemulsions at the lowest possible droplet size. The various emulsification process variables such as ratio of hydrocarbon to silicone surfactant, surfactant concentration, ratio of silicone oil to pine oil, oil weight fraction and sonication time have been studied. The optimal variables include the ratio of hydrocarbon to silicone surfactant of 80:20, surfactant concentration of 8%, ratio of silicone oil to pine oil of 80:20, oil weight fraction of 20% and 15 min of sonication time at 40% of the applied power. Nanoemulsions were found to be very stable with emulsion droplet size around 41 nm. In order to compare different emulsification techniques, emulsions were also prepared using the conventional method. Emulsions analyzed using SEM showed spherical droplets ranging from 40 to 120 nm. Atomic force microscopy was used to evaluate the bounciness, fluffiness and softness of fabric. From this study, it was found that stable nanoemulsion with a lowest possible droplet size of silicone and pine oil could be prepared by ultrasonic emulsification technique in order to deliver multiple properties when applied to fabric.     

Curcumin Loaded PEGylated Nanoemulsions Designed for Maintained Antioxidant Effects and Improved Bioavailability: A Pilot Study on Rats

The current study describes the experimental design guided development of PEGylated nanoemulsions as parenteral delivery systems for curcumin, a powerful antioxidant, as well as the evaluation of their physicochemical characteristics and antioxidant activity during the two years of storage. Experimental design setup helped development of nanoemulsion templates with critical quality attributes in line with parenteral application route. Curcumin-loaded nanoemulsions showed mean droplet size about 105 nm, polydispersity index <0.15, zeta potential of −40 mV, and acceptable osmolality of about 550 mOsm/kg. After two years of storage at room temperature, all formulations remained stable. Moreover, antioxidant activity remained intact, as demonstrated by DPPH (IC50 values 0.078–0.075 mg/mL after two years) and FRAPS assays. In vitro release testing proved that PEGylated phospholipids slowed down the curcumin release from nanoemulsions. The nanoemulsion carrier has been proven safe by the MTT test conducted with MRC-5 cell line, and effective on LS cell line. Results from the pharmacokinetic pilot study implied the PEGylated nanoemulsions improved plasma residence of curcumin 20 min after intravenous administration, compared to the non-PEGylated nanoemulsion (two-fold higher) or curcumin solution (three-fold higher). Overall, conclusion suggests that developed PEGylated nanoemulsions present an acceptable delivery system for parenteral administration of curcumin, being effective in preserving its stability and antioxidant capacity at the level highly comparable to the initial findings.     

一种新型W/O型微乳液制备超细Al2O3粉体的实验研究

向PEG+正丁醇/正庚烷/水溶液 (NaAlO2 )超声乳化后的W/O微乳液中通入CO2,将制得的凝胶焙烧后制备出了粒度100nm左右的Al(OH)3凝胶与Al2O3超细粉体,实验结果表明:乳化温度、表面活性剂与助表面活性剂之比及偏铝酸钠浓度是影响粉体粒度的主要影响因素.     

Experimental Study of Nanofluids Applied in EOR Processes

Nanoemulsions are small droplet-sized systems that have low surface tension and a small percentage of active material in their composition. In this study, low oil content nanoemulsion systems were developed for the use in enhanced oil recovery (EOR). The experiments were performed on a device capable of simulating petroleum reservoir conditions using sandstone rock cores. Nanoemulsions were obtained from a pre-selected microemulsion system composed of: RNX95 as surfactant, isopropyl alcohol as cosurfactant, kerosene as oil phase, and distilled water as aqueous phase. Different percentages of polyacrylamide were added to the systems obtained to evaluate the influence of viscosity in EOR results. The nanoemulsion droplet sizes ranged from 9.22 to 14.8 nm. Surface tension values were in the range of 33.6–39.7  dyn/cm. A nanoemulsion system with 2.5 wt% surfactant was used in EOR assays. The oil recovery was directly proportional to polymer percentage in the nanoemulsion, ranging from 39.6 to 76.8%. The total oil in the place recovery ranged from 74.5 to 90%.     

Mass transfer studies on multiple emulsion as a controlled mass release system

A novel type of multiple emulsions which contain a microemulsion in macrodroplets, was prepared by a two-step emulsification procedure. Mineral oil was used as the oil phase with a mixture of Aerosol OT and Span 20 as primary emulsifiers. A water-in-oil microemulsion was prepared by gradual addition of water in oil containing both these emulsifiers. This microemulsion system, when dispersed in an aqueous solution containing secondary emulsifier, produces water-in-oil-in-water (W/O/W) multiple emulsions. The release rate of solute dissolved in the internal aqueous phase was measured using the dialysis technique. A theoretical model describing the diffusion of a multiple emulsion system was developed, which predicts the half-life for 50% of the internal solute to diffuse to the external phase. Experimental results showed the stability of multiple emulsions improved significantly upon using a thermodynamically stable microemulsion as a primary emulsion and a polymeric surfactant as a secondary emulsifier. As a resull, half-life of these multiple emulsions is greater than that of conventional multiple emulsions.     

W/O型微乳液碳化法制备超细氢氧化铝与氧化铝粉体

PEG 正丁醇／正庚烷／水溶液(铝酸钠)体系W／O微乳液中通入二氧化碳，焙烧后制备出了纯度大于99.9％、粒度小于80nm的氢氧化铝与氧化铝纳米粉体，实验结果表明乳化温度、表面活性剂与助表面活性剂之比及水相的浓度是决定粉体粒度的主要影响因素。     

Potential of Green Nanoemulsions in Removal of Congo Red from Aqueous Solution

In the present study, potential of green nanoemulsions in the removal of Congo red (CR) from aqueous solution was investigated. Nanoemulsions were prepared by low energy emulsification technique using ethyl acetate (EA), Triton-X100, ethylene glycol (EG), and water. Nanoemulsions were characterized for thermodynamic stability, self-nanoemulsification efficiency, droplet size, polydispersity, viscosity, refractive index, and transmittance. Adsorption studies were carried out for contact time of 10, 15, and 20 min. The influence of contact time and EA & Triton-X100/EG concentrations on droplet size, viscosity, and % CR removal was also investigated. It was observed that droplet size, viscosity, and % CR removal were significantly influenced by EA and Triton-X100/EG concentrations. However, contact time had negligible/little impact on % CR removal. Based on the lowest droplet size (14.3 nm), lowest viscosity (11.4 cp), and highest % CR removal efficiency (91.6%), the nanoemulsion F7 containing 5% w/w of EA, 33.3% w/w of Triton-X100, 16.7% w/w of EG, and 45% w/w of water was optimized as the best formulation for the removal of CR from its bulk aqueous solution. These results indicated the potential of green nanoemulsions in the removal of toxic dyes such as CR from its aqueous solution via liquid-liquid adsorption.     

Investigating Factors Affecting Water-In-Diesel Fuel Nanoemulsions

In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20) sorbitan monooleate, with different Hydrophilic–Lipophilic Balance (HLB) values (9.6, 9.8, 10, 10.2 and 10.4) were prepared to achieve the optimal HLB value. Three mixed surfactant concentrations were prepared at 6, 8 and 10 wt% to identify the optimum concentration. Five emulsions with different water contents: 5, 6, 7, 8 and 9 % (wt/wt) were prepared using a high energy method under the optimum conditions (HLB = 10 and mixed surfactant concentration = 10 %). The effect of the HLB value, mixed surfactant concentration and water content on the droplet size has been studied. The interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the results obtained, it was found that the mean droplet size was formed between 49.5 and 190 nm depending on the HLB value, surfactant concentration and water content of the blended emulsifiers.