在DMSO水溶液中CTAB胶束的粒径分布

利用激光光散射和染色 -电镜技术研究了在二甲基亚砜 ( DMSO)水溶液中十六烷基三甲基溴化铵 ( CTAB)胶束的粒径分布以及粒径分布、聚集数和扩散系数等受 KBr浓度的影响和随时间的改变     

温度及无机盐对LMEE和SDS混合溶液表面张力的影响

通过表面张力的测定,研究了温度和不同无机盐对月桂酸甲酯乙氧基化物(laurylmethylesterethoxylate,简称LMEE)与十二烷基硫酸钠(SDS)复配物表面张力及临界胶束浓度(CMC)的影响。研究表明:混合体系的CMC在很宽的复配比例内出现最低值,25℃、未加无机盐时可使CMC最低降至3 8×10-5mol/L;温度对复配体系表面张力的影响较小,温度上升复配物的CMC略有降低。3种价态无机盐的加入均可使复配物的CMC有所降低,但与单一表面活性剂相比,温度和无机盐对复配物的CMC影响均不大,说明复配体系的抗温变及抗盐能力均有增强。     

二元脂肪酸对十六烷基三甲基溴化铵胶束化行为的影响

利用表面张力法研究了不同温度下草酸、丙二酸、丁二酸、己二酸和辛二酸对十六烷基三甲基溴化铵(CTAB)胶束化行为的影响,并计算了胶束形成的热力学函数,讨论了焓-熵补偿现象。实验结果表明,上述脂肪酸均能够促进CTAB胶束的形成,随着2个羧基间烷基链长度的变化,使CTAB的临界胶束浓度下降的能力由强到弱的顺序是辛二酸、草酸、己二酸、丁二酸和丙二酸,温度升高有利于CTAB在二元脂肪酸溶液中的胶束形成,胶束化是自发的,主要驱动来自熵;胶束化存在焓-熵补偿现象,补偿温度T c=(301±2)K。     

阴阳离子表面活性剂复配体系的聚集行为

用芘(Py)荧光探针法测定了添加少量十六烷基三甲基溴化胺(CTAB)后,十二烷基硫酸钠(SDS)的临界胶束浓度(CMC)和胶束聚集数(Nm)。在一定范围内,SDS的CMC与CTAB的添加量〔x=c(CTAB)/c(SDS)〕有如下定量关系:ln〔CMC/(mmol/L)〕=0.69-10.48x。当x=1/80时,SDS的胶束聚集数为92。x=1/40时,SDS的胶束聚集数为122。SDS的胶束聚集数随着CTAB的添加量迅速增加。因此,阴阳离子混合表面活性剂作为合成介孔催化剂的模板剂,可以调控介孔催化剂的孔径大小。     

糖基硼酸酯表面活性剂的合成及表面活性的研究

以硼酸、葡萄糖和癸酸氯为原料合成了糖基硼酸酯(即硼酸双葡萄糖酯双癸酸酯,简称DGBR),并利用红外对其结构进行了表征和分析,结果显示其结构和设计产物结构相符合。并采用表面张力法确定了DGBR的临界胶束浓度(CMC)和临界胶束浓度下的表面张力(γCMC),其CMC、γCMC和文献值相接近;考察了不同Na Cl浓度对DGBR表面性能的影响,并计算了饱和吸附量(Γmax)和单分子饱和吸附面积(Аmin)等参数,随着Na Cl浓度的增加,其表面性能增强。     

槐糖脂与聚丙烯酰胺的相互作用

通过表面张力和表观黏度的测定,研究了槐糖脂与聚丙烯酰胺(PAM)的相互作用。结果表明,加入PAM,槐糖脂溶液的表面张力略有升高,临界胶束浓度(CMC)由约30 mg/L升高为约40 mg/L,但槐糖脂/PAM混合溶液的表面张力主要受槐糖脂浓度的影响。温度升高,混合溶液的表面张力略有降低,CMC保持不变;加入氯化钠,混合溶液的表面张力略有降低。由于槐糖脂与PAM的"疏水微区"相互作用形成混合胶束,加入槐糖脂,PAM溶液的表观黏度出现不同程度的升高,当槐糖脂浓度为30 mg/L时,PAM溶液的表观黏度最高。槐糖脂与聚丙烯酰胺复配在降低表面张力的同时能提高体系的表观黏度,适用于三次采油技术。     

槐糖脂与聚丙烯酰胺的相互作用

通过表面张力和表观黏度的测定,研究了槐糖脂与聚丙烯酰胺(PAM)的相互作用。结果表明,加入PAM,槐糖脂溶液的表面张力略有升高,临界胶束浓度(CMC)由约30 mg/L升高为约40 mg/L,但槐糖脂/PAM混合溶液的表面张力主要受槐糖脂浓度的影响。温度升高,混合溶液的表面张力略有降低,CMC保持不变;加入氯化钠,混合溶液的表面张力略有降低。由于槐糖脂与PAM的"疏水微区"相互作用形成混合胶束,加入槐糖脂,PAM溶液的表观黏度出现不同程度的升高,当槐糖脂浓度为30 mg/L时,PAM溶液的表观黏度最高。槐糖脂与聚丙烯酰胺复配在降低表面张力的同时能提高体系的表观黏度,适用于三次采油技术。     

2-丙烯酰胺基辛烷基磺酸钠的合成及其胶束化行为研究

以丙烯腈与1-辛烯为主要原料,合成了表面活性单体2-丙烯酰胺基辛烷基磺酸钠(NaAMC8S)。在n(1-辛烯)∶n(丙烯腈)∶n(发烟硫酸)=1∶6∶1,反应温度25℃,反应时间24h,产品收率(按1-辛烯计)为82.2%。用红外光谱、核磁共振波谱、高分辨质谱和X射线能谱确认了NaAMC8S的化学结构。用电导法与表面张力法测定了NaAMC8S的临界胶束浓度(CMC)。用稳态荧光光谱法测定了CMC和胶束的微极性。结果表明,25℃时,用电导法和表面张力法测得NaAMC8S的CMC分别为44.75mmol/L和51.76mmol/L,对应的表面张力为50.61mN/m;且CMC随温度变化很小。     

十二烷基苯磺酸钠/聚氧乙烯(23)月桂醚复配体系性能的研究

在35℃时通过表面张力法研究了阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和非离子表面活性剂聚氧乙烯(23)月桂醚(Brij35)复配体系在不同配比下的临界胶束浓度(CMC)和降低表面张力效率方面的作用。结果表明:SDBS和Brij35的物质的量比为3∶7时,降低表面张力的效率最高,其CMC为0.2 mmol/L,明显低于单一组分;并在总物质的量浓度一定时,测定了复配体系的稳定性和润湿性。     

去甲肾上腺素电化学行为的胶束效应

利用循环伏安法研究了不同pH值条件下去甲肾上腺素(NE)在玻碳电极上电化学氧化过程的胶束效应.结果表明,NE在玻碳电极上的氧化峰电位(Epa)和峰电流(Ipa)与表面活性剂的种类及浓度有关.Epa与Jpa值在表面活性剂的临界胶束浓度值(CMC)附近有一个突变,而在CMC以上时,Epa和Ipa值基本上不再随表面活性剂浓度的变化而改变.pH=6.8时,Epa值在水溶液中为364 mV,在CTAB胶束溶液中为420 mV,在SDS胶束溶液中为284 mV.表明SDS对NE的电化学氧化具有催化作用,而CTAB则阻化了NE的电化学氧化过程.     

Interaction of Azo Dye with Cationic Surfactant Under Different pH Conditions

The aggregation induced by Alizarin Yellow R (AYR) in the cationic surfactant, cetyltrimethylammonium bromide (CTAB), was investigated by measuring their UV–visible absorption spectra. Conductance measurements as a function of surfactant concentration below and above the critical micelle concentration (CMC) were studied. CTAB aggregation takes place at the concentration far below its normal CMC in the presence of AYR. Both hydrophobic and electrostatic interactions affect the aggregation process in aqueous solution. The dye effect on the CMC of CTAB was noted by a specific conductivity method as well. AYR–CTAB binding constant (K_s) and water–micelle partition co-efficient (K_x) were quantified with the help of mathematical models employed to determine the partitioning of organic additives in the micellar phase. The number of dye molecules per micelle was estimated at particular CTAB concentrations above CMC, during this study.     

Interaction of cetyltrimethylammonium bromide with drug in aqueous/ electrolyte solution: A combined conductometric and molecular dynamics method study

Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 K.CFH drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed systems.The decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the cases.The ΔG_m~0 values are found to be negative in present study systems demonstrated the stability of the solution.The values of ΔH_m~0 and ΔS_m~0 reveal the existence of hydrophobic and electrostatic interactions between CFH and CTAB.The thermodynamic properties of transfer for the micellization were also evaluated and discussed in detail.Molecular dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and CTAB.In water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the micelle.This hydrophobic core region is highly conserved and protected.In addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions.     

Alcohols Effect on Critic Micelle Concentration of Polysorbate 20 and Cetyl Trimethyl Ammonium Bromine Mixed Solutions

In this research, the micellar behavior of a cationic surfactant, cetyl trimethyl ammonium bromide (CTAB) and an nonionic surfactant, polysorbate 20 (Polyoxyethylene (20) sorbitan monolaurate) in different alcohol solutions media was investigated over the temperature range 293.15–313.15 K. The interaction between two surfactants in binary systems can be determined by calculating the values of their β parameters. The critical micelle concentrations (CMC) of the micelles were determined from the surface tension, the conductivity at different temperatures. The CMC behavior of CTAB and polysorbate 20 was analyzed in terms of the effect of temperature and the increase in the alcohol carbon chain. Changes in the critical micelle concentration of mixed surfactant systems of different alcohol solutions were measured. The CMC decreased sharply as the hydrocarbon chain length of the alcohols becomes larger. This shows that the more hydrophobic alcohols are, the more marked a decrease in CMC is observed.     

Some Surface Properties of Polysorbates and Cetyl Trimethyl Ammonium Bromine Mixed Systems

Mixed surfactant solutions consisting of cationic/nonionic surfactants were prepared in different compositions of the components in aqueous solution in order to determine the surface properties. The critical micelle concentration (CMC) of aqueous solutions of the individual surfactants cetyl trimethyl ammonium bromide (CTAB) and polysorbate nonionics, and their mixtures are determined at different proportions. The results show that there is synergistic behavior in mixtures at higher mole fraction of nonionic surfactant. The effect of the alkyl chain on the CMC is also determined.     

Physicochemical Studies on the Interfacial and Micellization Behavior of CTAB in Aqueous Polyethylene Glycol Media

Interfacial and micellization behavior of cetyltrimethylammonium bromide (CTAB) have been studied in aqueous polyethylene glycol (PEG) mixed solvent systems of varying concentrations and molar mass. Interfacial behavior of CTAB was investigated by the equilibrium surface tension method. Conductance studies of surfactant solutions under different condition helped in determining the critical micelle concentration (CMC) and degree of dissociation of CTAB micelles. In addition, the limiting molar conductivity of surfactant and micellar species were evaluated from the differential plots. The CMC of CTAB was found to increase with increasing PEG concentration as well as its molar mass, although, the process of interfacial adsorption and micellization was found to be spontaneous, as evidenced by negative free energy change. The viscosity of CTAB micelles in aqueous-PEG mixtures was found to increase with the increase in PEG concentration and molar mass. Dynamic light scattering measurements revealed a size enhancement effect contributed by the PEG oligomers. An increase in the CMC of CTAB and the subsequent presence of a higher number of ionic species in their dissociated form was further established by an overall increase in the zeta potential value in the presence of PEG oligomers. It is proposed that the PEG could wrap around the micelles through their conformational changes. Results also suggest that PEG oligomers could give solvophobic effect which enhances the CMC of CTAB compared to that in pure water.     

Effect of cefoperazone sodium on the physicochemical properties of surfactants

The effects of cefoperazone sodium (CS), a pharmaceutical compound, on the critical micelle concentration (CMC) of surfactants with different charges [cetyl trimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Triton X-100], the cloud point of Triton X-100, and the Krafft temperatures of SDS and CTAB were studied. The interaction of CS with differently charged surfactants was determined by ultraviolet and fluorescence spectrophotometry. The results show that with increasing CS concentration, the Krafft temperature increases and the CMC decreases in the SDS/H₂O system, whereas the opposite results are obtained in the CTAB/H₂O system. Both the cloud point and the CMC of Triton X-100 increase with the addition of CS. The above results are attributed to the different micellar interactions between CS and surfactants with different charges.     

Investigation on the Properties of Aqueous Foams Stabilized by Cetyltrimethylammonium Bromide in Terms of Free Drainage and Bubble Size

Although foams stabilized by surfactants have been the subject of massive investigations and great achievements were made over the past few years, many questions concerning their properties are still not well understood. The aim of this study is to examine the effect of the cetyltrimethylammonium bromide (CTAB) concentration on the foam properties and illustrate the interaction between liquid drainage and bubble size evolution. Experiments were carried out at varying CTAB concentrations ranging from 0.1 to 5.0 times the critical micelle concentration (CMC), where the variation of the liquid content of foam and bubble size was simultaneously determined using a commercially available FoamScan device. The results showed that the foam properties (both foamability and foam stability) of CTAB were largely dependent on the surfactant concentration when concentrations c < CMC but this effect did not scale linearly with concentration. When c ≥ CMC, both foamablity and foam stability were nearly concentration independent, while the latter showed a small decrease due to the formation of micelles. In addition, the correlation between free drainage and bubble size evolution indicated that the increase of bubble size could indeed enhance the foam drainage.     

荧光法研究表面活性剂CTAB与蛋白质的相互作用

应用荧光光谱法研究了十六烷基三甲基溴化铵(CTAB)与牛血清白蛋白(BSA)的相互作用机制。实验结果表明,CTAB主要以静态猝灭的方式使得BSA的荧光强度显著降低;求得它们在l6℃和25℃温度下的结合常数以及结合位点数n;计算得出CTAB与牛血清白蛋白的相关热力学参数(25℃);CTAB和BSA主要凭借范德华力和氢键作用结合。同时以芘为荧光探针、二苯甲酮为猝灭剂,用稳态荧光探针法测定了CTAB的临界胶团浓度(CMC)与不同表面活性剂浓度下的胶团聚集数(N)并研究了BSA对其临界胶团聚集数的影响。且用同步荧光技术考察了十六烷基三甲基溴化铵对牛血清白蛋白构象的影响。     

Study of Micellization of Sodium Dodecyl Sulfate in Non-Aqueous Media Containing Lauric Acid and Dimethylsulfoxide

Interactions between dimethylsulfoxide (DMSO), lauric acid (LA) and anionic surfactant, sodium dodecyl sulfate (SDS) in non‐aqueous media have been studied in detail using conductometric, volumetric, and ultrasonic speed techniques. Conductivities, densities and ultrasonic speeds of 1 × 10^?3 to 11 × 10^?3 m SDS solutions in a mixture of LA (0.10 m) and DMSO between 298.15 and 313.15 K have been measured. The experimental data have been correlated against temperature and concentration of SDS using standard relations. The critical micelle concentration (CMC) values have been determined by using different methods like conductance, density and ultrasonic speed. All the methods yielded identical CMC values. The measured data were used to calculate various useful thermodynamic parameters like standard free energy, , enthalpy, , and entropy, , of micelle formation. From the density data of the surfactant, the change of the apparent molar volume upon micellization has been calculated. Density and ultrasonic speed data were used to evaluate the apparent molar adiabatic compressibility for the micelle of the surfactant at different temperatures over a wide concentration range.