Experimental comparison of Triton X-100 and sodium dodecyl benzene sulfonate surfactants on thermal performance of TiO2–deionized water nanofluid in a thermosiphon

This study investigates how TiO₂/deionized water nanofluids affect the thermal performance of a two-phase closed thermosiphon (TPCT) at various states of operation, according to the surfactant types. A straight copper tube with an inner diameter of 13 mm, outer diameter of 15 mm, and length of 1 m was used as the TPCT, i.e., heat pipe. The nanofluid utilizing in experiments was prepared by mixing the TiO₂ nano-particles at the rate of 1.3% and a surfactant at the rate of 0.5% with deionized water. The surfactants used for lowering the surface tension give rise to prevent the flocculation in nanofluids. In order to see the influences of the surfactants on the nanofluid properties, two types surfactants, Triton X-100 and sodium dodecyl benzene sulfonate (SDBS), were selected as nonionic and ionic surfactants and used in this study. The nanofluid was charged with in the ratio of 33.3% (equals to 44.2 ml) of the volume of the TPCT. To be able to make experimental comparisons, three different working fluids prepared under the same conditions in the same heat pipe were tested at three different heating powers (200, 300, and 400W) and three different coolant water flow rates (5, 7.5, and 10 g/s). The experiments were conducted for both TiO₂ and Triton X 100–deionized water nanofluid and TiO₂ and SDBS–deionized water nanofluid. The findings obtained from the tests were also compared to each other for showing off to what extent a surfactant affects the nanofluid properties. The maximum improvement in the thermal resistance was achieved by 43.26% in the experiment realized at 200 W input power and 7.5 g/s cooling water mass flow rate, in which the working fluid is TiO₂ and SDBS–deionized water nanofluid.     

丝素肽和β-环糊精包合作用及表面活性剂影响

在pH为2和包合时间是60min的最佳条件下,采用光谱法（荧光光谱与紫外-可见光谱）测得β-环糊精（β-CD）与丝素肽构成的包合体系包合比均是2∶1,平均包合常数是3.3×105。两种阴离子表面活性剂十二烷基硫酸钠、十二烷基苯磺酸钠对包合体系有阻抑作用,阳离子表面活性剂十六烷基三甲基溴化铵和非离子表面活性剂＂平平加O＂对包合体系没有影响。     

表面活性剂敏化稀土荧光探针对环丙沙星药物的测定研究

稀土铽离子能与环丙沙星形成络合物,并发射铽离子的特征荧光,加入表面活性剂SDBS能大大增强体系的荧光强度,由此建立了表面活性剂敏化的铽离子荧光探针测定环丙沙星的方法。用1 cm 石英比色池在激发波长为300 nm, 发射波长为545 nm处测定其荧光强度。在最佳测试条件为pH=8.0～8.5, Tb3+ 浓度为5.0×10-5 mol·L-1, SDBS浓度为8.0×10-4 mol·L-1时,环丙沙星的浓度与体系的荧光强度呈线性关系,线性范围为2.0×10-8 mol·L-1～2.5×10-6 mol·L-1, 相关系数为0.999 6,检出限为4.0×10-9 mol·L-1。该法可用于不同剂型环丙沙星药物的测定。     

氨水-Fe2O3纳米流体稳定性影响因素分析

为了将纳米颗粒的强化传热传质作用应用于氨水吸收制冷中,提出了在氨水溶液中添加Fe203纳米颗粒和表面活性剂十二烷基苯磺酸纳（SDBS）的纳米流体的配制方法,并通过沉降试验和吸光度测试方法对其稳定性进行了实验研究。研究了活性剂质量分数、超声分散时间和氨水浓度对稳定性的影响,确定了Fe2O3-氨水纳米流体分散的最佳工艺为：...     

Sensitive Spectrofluorimetric Determination of Cytochrome c with Spirocyclic Rhodamine B Hydrazide in Micellar Medium

A new spectrofluorimetric method for the determination of cytochrome c using spirocyclic rhodamine B hydrazide (RBH) as fluorogenic reagent in the presence of sodium dodecylbenzene sulfonate (SDBS) surfactant micelles was developed. The method was based on the reaction of cytochrome c with RBH, a colorless, nonfluorescent spirolactam of rhodamine B in SDBS micelles to give highly fluorescent rhodamine B and hence led to a large increase in fluorescence intensity. The dynamic range and detection limit for the determination of cytochrome c are 4.0–120 ng ml⁻¹ and 0.87 ng ml⁻¹ (3σ), respectively. The optimal conditions for the detection of cytochrome c were evaluated and the possible detection mechanism was also discussed.     

Dynamics of counterion binding during acoustic nebulisation of surfactant solutions

A metal ion (Cu(2+)) and a complex copper species, copper (II) bis-bipyridine, were used as alternate counterions in an aqueous surfactant solution of sodium dodecylbenzenesulfonate (SDBS) to investigate the dynamics of counterion interactions in an acoustic field. Sonoluminescence spectral studies showed that such counterions were able to replace sodium ions at the interface, even when the interface was rapidly oscillating under the acoustic field. Ultrasound induced nebulisation was then used to probe the interfacial profile of surfactant and bound counterions in a dynamic environment. At low bulk concentrations, the copper (II) bis-bipyridine cation was more effective at enhancing the loading of the dodecylbenzenesulfonate anion on the interface, due to its documented greater binding ability. However, at higher bulk concentrations, the movement of this cation is limited by its larger size and the smaller Cu(2+) cation is more effective in enhancing the loading of the dodecylbenzenesulfonate anion. The results show that under dynamic conditions, the surface concentrations are governed by mass transfer kinetics rather than equilibrium thermodynamics.     

均匀设计优化共振瑞利散射法测定水中阴离子表面活性剂

在均匀设计优化后的反应条件下,研究了含吩嗪结构类染料健那绿（JG）与十二烷基苯磺酸钠（SDBS）作用的共振瑞利散射光谱,建立一种简便快速的环境水样中阴离子表面活性剂（AS）均匀设计优化共振瑞利散测定新方法。在pH12.4时,加入SDBS导致JG共振瑞利散射剧烈增强,在λem=λex=625nm处,存在一共振瑞利散射峰,其强度与SDBS的浓度呈线性关系,方法的线性范围为0—3.48mg·mL^-1,检出限为17.8ng·mL^-1。方法简便、快速,与单因素轮换法实验结果比较,实验条件更优化,可直接用于测定环境水样中的阴离子表面活性剂。     

吖啶橙与表面活性剂的作用及其在测定蛋白质中的应用

运用紫外光谱法和荧光光谱法研究了染料吖啶橙中加入表面活性剂十二烷基苯磺酸钠以及牛血清白蛋白后紫外光谱和荧光光谱的变化情况。以吖啶橙在十二烷基苯磺酸钠中生成的二聚体作为荧光探针,讨论了与牛血清白蛋白相互作用情况。采用荧光呈现法对牛血清白蛋白进行了测定,结果表明,该方法反应灵敏,速度快,线性范围为0～4.17×10-7 mol·L-1, 相对标准偏差为1.9%, 检出限为8.73×10-10 mol·L-1。     

Quantitative ToF-SIMS studies of protein drug release from biodegradable polymer drug delivery membranes

Biodegradable polymers are of interest in developing strategies to control protein drug delivery. The protein that was used in this study is Keratinocyte Growth Factor (KGF) which is a protein involved in the re-epithelialization process. The protein is stabilized in the biodegradable polymer matrix during formulation and over the course of polymer degradation with the use of an ionic surfactant Aerosol-OT (AOT) which will encapsulate the protein in an aqueous environment. The release kinetics of the protein from the surface of these materials requires precise timing which is a crucial factor in the efficacy of this drug delivery system.Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used in the same capacity to identify the molecular ion peak of the surfactant and polymer and use this to determine surface concentration. In the polymer matrix, the surfactant molecular ion peak was observed in the positive and negative mode at m/z 467 and 421, respectively. These peaks were determined to be [AOT + Na⁺] and [AOT − Na⁺]. These methods are used to identify the surfactant and protein from the polymer matrix and are used to measure the rate of surface accumulation. The second step was to compare this accumulation rate with the release rate of the protein into an aqueous solution during the degradation of the biodegradable film. This rate is compared to that from fluorescence spectroscopy measurements using the protein autofluorescence from that released into aqueous solution [C.M. Mahoney, J. Yu, A. Fahey, J.A.J. Gardella, SIMS depth profiling of polymer blends with protein based drugs, Appl. Surf. Sci. 252 (2006), 6609-6614.].     

Compatibility Studies of Polysaccharide-Based Natural and Synthetic Polymers in Aqueous Solution

Compatibility of polysaccharide-based natural polymers, xanthan gum (Xn), tragacanth gum (Traga) and acacia gum (Ac), with synthetic polymer, polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG) in aqueous solution has been investigated using the related acoustical parameters at room temperature, 303 K. The concentration of synthetic polymers PVP and PEG was varied to understand the nature of solute–solvent interaction in the polysaccharide-based natural/synthetic polymer in aqueous solution. FT-IR studies were also carried out for vibration assignment and confirmation of compatibility.     

The removal of sodium dodecylbenzene sulfonate surfactant from water using silica/titania nanorods/nanotubes composite membrane with photocatalytic capability

This paper reports experimental results on removal of sodium dodecylbenzene sulfonate (SDBS), using silica/titania nanorods/nanotubes composite membrane with photocatalytic capability. This multifunctional composite membrane has been successfully prepared from colloidal X-silica/titania sols (X denotes molar percent of silica) by the sol-gel technique. The prepared nanorods/nanotubes composite membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), scanning probe microscope (SPM) and UV-vis diffuse reflectance spectra (DRS). XRD patterns confirmed that the embedding of amorphous silica into nanophase titania matrix helped to increase the thermal stability of titania and control the size of titania particles. The small size titania particles with anatase phase played an important role in formation of silica/titania nanorods/nanotubes composite membranes with photocatalytic capability. The percentage of anatase phase titania reached 93% when 20%-silica/titania nanorods/nanotubes composite membrane calcined at 400 °C for 2 h. Most (95%) of the pore volume was located in mesopores of diameters ranging from 1.4 to 10 nm. The experimental results showed that the removal of SDBS achieved 89% after 100 min by combining the photocatalysis with membrane filtration techniques. Although the SDBS was not completely decomposed by photocatalysis, the degradation of the SDBS helped to enhance composite membrane flux and prevent membrane fouling. It was possible to treat successfully surfactant wastewater using multifunctional silica/titania nanorods/nanotubes composite membrane by means of a continuous process; this could be interesting for industrial applications.     

细圆管内纳米悬浮液对流换热的实验研究

实验研究了细圆管内氧化铜纳米颗粒悬浮换热特性。试验段的管径为0.68mm、1.01mm和1.28mm,氧化钢纳米颗粒平均粒径为50um,悬浮液中氧化铜纳米颗粒质量分数分别为0.02,0.04和0.06,分散剂十二烷基苯磺酸钠(SDBS)质量的分数为0.02。为进行对比分析,还测试了水的换热特性。实验结果表明,在所研究的尺寸下,层流时去离子水的努谢尔特数Nu要高于已有液体对流换热关联式计算之值,纳米颗粒悬浮液的对流换热系数高于水的,且纳米颗粒的质量分数越高,悬浮液的对流换热系数越大。随着流动从层流向湍流的转换,强化效果也越明显。     

Effect of cationic and anionic surfactants on morphology and luminescent properties of YVO4: Bi,Eu3+ red phosphors

Using cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS), respectively, YVO₄: Bi, Eu³⁺ red phosphors were prepared by a facile reaction chemistry method and their morphology, structure and luminescent properties were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and fluorescence spectrometer. The results showed that the introduction of cationic and anionic surfactants not only greatly influenced their morphology, but induced a remarkable change XRD patterns. The reason that causes the variation of these properties for YVO₄: Bi, Eu³⁺ red phosphors was concluded to be related to different surfactants.     

Synthesis of nanoparticles and preparation and characterization of nanopolymer matrix composites

In this study, nano α-alumina particles were synthesized by a sol–gel method using aqueous solutions of aluminum isopropoxide and 0.5?M aluminum nitrate. 1/3-benzene disoulfonic acid disodium salt (SDBS) and fluoride were used as surfactant stabilizing agent and additive, respectively. Results indicated that the finest size for nonagglomerated nanoalumina particles (15–20?nm) was achieved at 950?°C. The next part was about preparing PP nanocomposite containing nano α-Al₂O₃ particles. Mechanical tests, such as tensile, flexural, and impact tests showed that mechanical properties of the composite were enhanced by addition of nano α-Al₂O₃ particles and dispersant to the polymer. However, higher concentration of nano α-Al₂O₃ loading resulted in reduction of those mechanical properties, which could be due to agglomeration of nano α-Al₂O₃ particles. Transmission and scanning electron microscopic observations of the nanocomposites also showed that fracture surface became more roughened by increasing the content of filler loading from 1 to 4% wt.     

Premicellar and micelle formation behavior of aqueous anionic surfactants in the presence of triphenylmethane dyes: protonation of dye in ion pair micelles

The premicellar and micelle formation behaviors of four cationic triphenylmethane dyes, viz, Pararosaniline (RN), Crystal violet (CV), Ethyl violet (EV), and Malachite green (MG), in aqueous anionic surfactant solutions of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium dodecyl sulfonate (SDSN) have been studied by spectral and surface tension measurements. The study was carried out within a pH range where the dyes are stable in their quinoid forms. The dyes have been found to form dye–surfactant ion pairs (DSIPs) with the surfactants, at the surfactant concentrations well below their critical micelle concentration, CMC*. The DSIPs behave like nonionic surfactants and form an air–water interfacial monolayer. The DSIPs have a lower critical micelle concentration (CMC_IP), greater efficiency, and lower effectiveness than the corresponding pure surfactants. As the surfactant concentration is increased below the CMC*, the DSIPs start forming micelles of their own where the dye gets protonated and exists as a protonated dye–surfactant ion pair (PDSIP) in the ion pair micelles. As the concentration of the surfactant exceeds the CMC* of the pure surfactant, the protonation reverses gradually with the dye remaining in the micelles in solubilized form and the DSIPs in the air–water interfacial monolayer are replaced by pure surfactants. The distorted helical isomeric form (isomer B) of the dyes is favored in the PDSIPs. Copyright © 2009 John Wiley & Sons, Ltd.     

Solution-phase synthesis of nanomaterials at low temperature

This paper reviews the solution-phase synthesis of nanoparticles via some routes at low temperatures, such as room temperature route, wave-assisted synthesis (γ-irradiation route and sonochemical route), directly heating at low temperatures, and hydrothermal/solvothermal methods. A number of strategies were developed to control the shape, the size, as well as the dispersion of nanostructures. Using diethylamine or n-butylamine as solvent, semiconductor nanorods were yielded. By the hydrothermal treatment of amorphous colloids, Bi₂S₃ nanorods and Se nanowires were obtained. CdS nanowires were prepared in the presence of polyacrylamide. ZnS nanowires were obtained using liquid crystal. The polymer poly (vinyl acetate) tubule acted as both nanoreactor and template for the CdSe nanowire growth. Assisted by the surfactant of sodium dodecyl benzenesulfonate (SDBS), nickel nanobelts were synthesized. In addition, Ag nanowires, Te nanotubes and ZnO nanorod arrays could be prepared without adding any additives or templates. Supported by the National Basic Research Program of China (Grant No. 2005CB623601) and the National Natural Science Foundation of China (Grant No. 20431020)     

偏振同步光散射和同步光散射光谱区分与同时测定奎宁和奎尼丁对映异构体

在酸性缓冲溶液中,阴离子表面活性剂十二烷基苯磺酸钠SDBS能与金鸡纳类生物碱药物体系中一对对映异构体QN和QD作用产生增强的同步光散射(synchronous light scattering,SLS)信号,本文首先利用偏振同步光散射(polarized synchronous light scattering)信号,建立了同步光散射偏振度(P)区分QN和QD这对对映异构体,同时利用同步散射光谱和双标准曲线计量分析法对2种金鸡纳类生物碱药物进行同时测定,并将该方法应用于尿样中QN和QD的同时测定,结果令人满意。     

Photoluminescence and optical characterization of CdS nanoparticles prepared by solid-state method at low temperature

The photoluminescence (PL) and optical properties of CdS nanoparticles prepared by the solid-state method at low temperature have been discussed. The effects of NaCl and anionic surfactant SDBS (sodium dodecylbenzene sulfonate) on the luminescent properties of CdS nanophosphors prepared using this method, without the inert gas or the H₂S environment, were studied separately. The synthesized products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), and energy dispersive X-ray spectroscopy (EDAX). UV–VIS absorption and PL spectra were also studied. XRD studies confirmed the single-phase formation of CdS nanoparticles. TEM micrograph revealed the formation of nearly spherical nanoparticles with a diameter of 2.5 nm. The PL emission for the CdS shows the main peak at 560 nm with a shoulder at 624 nm, with an increase in the PL intensity after the addition of SDBS. The effect of Mn doping on PL intensity has also been investigated. The PL spectra show that the emission intensity decreases as the dopant concentration increases.     

Microphase separation in polymer solutions containing surfactants

A microphase separation in solutions containing a polymer and a mixture of two solvents, one of which consists of amphiphilic molecules (surfactant), is considered theoretically in the weak-segregation regime. A surfactant molecule is described as a dimer consisting of hydrophobic and polar parts. The energy gain due to the orientation of surfactant molecules can lead to the appearance of non-homogeneities in the solution, where density fluctuations cause the orientational ordering of surfactant molecules. The difference in the interaction energies of hydrophobic and polar groups of a surfactant with solvent is considered as a main reason for orienting surfactant molecules. The free energy is calculated for various morphologies (lamellar, cylindrical hexagonal, spherical particles arranged at different cubic lattices). The phase diagrams are presented. With worsening the solvent quality, the transitions from disordered to a macro-separated state at low polymer and surfactant concentrations or to a body-centered-cubic, then hexagonal, and then lamellar structure at high polymer and surfactant concentrations are predicted. The amphiphilicity degree of surfactant molecules should exceed a certain critical value to make a microstructure formation possible. The period of the lamellar microstructure decreases with increasing the surfactant and polymer concentrations.     

硫杂杯芳烃基胶束自组装荧光化学传感器制备及其性能研究

以对叔丁基硫杂杯[4]芳烃（TCA）为受体、苝和十二烷基苯磺酸钠（SDBS）分别为荧光体和自组装模板剂,通过在水中的胶束自组装作用制备得到一种新型的“ON–OFF”型Cu2+荧光化学传感器。论文选用荧光猝灭率为考察指标,详细考察了受体TCA用量、自组装模板剂SDBS浓度、Cu2+浓度和共存金属离子等影响因素对胶束自组装荧光化学传感器Cu2+检测性能的影响情况。实验结果表明,当受体TCA与荧光体苝的摩尔浓度比值达到1 000,自组装模板剂SDBS浓度为50 mmol·L-1,该荧光化学传感器对水中铜离子具有较好的检测能力,待测Cu2+浓度在一定浓度范围内与荧光猝灭率呈线性相关。此外,荧光化学传感器的Cu2+检测性能基本不受Pb2+, Cd2+, Mn2+, Na+, K+, Ca2+, Mg2+, Al3+,Ni2+,Zn2+等共存金属离子干扰。该胶束自组装荧光化学传感器对Cu2+的选择性检测性能主要归因于胶束表面活性剂分子层中TCA受体对Cu2+的识别作用,而传感器荧光猝灭主要基于胶束内部的电荷转移或能量转移机制。