稳态荧光探针法测定临界胶束聚集数

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SDS和AS的胶束聚集数(Nm).以芘的饱和水溶液为溶剂配制表面活性剂溶液,二苯甲酮的适宜浓度取小于1.00 mmol•L－1时,可以获得满意的实验结果.当表面活性剂溶液浓度为5～9倍cmc时,Nm随表面活性剂浓度增大而线性增大,而随温度的变化略有波动.cSAA=cmc时,Nm值为一本征值,定义为临界胶束聚集数[Nm].[Nm]值可从Nm－cSAA实验曲线外延得到.25℃时SDS的临界胶束聚集数[Nm]为57;40℃时SDS的[Nm]为49,AS的[Nm]为55.     

稳态荧光探针法研究烷基苄基聚氧乙烯醚丙烷磺酸钠的聚集行为

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合成的3种高纯的烷基苄基聚氧乙烯醚丙烷磺酸钠的临界胶束浓度、不同表面活性剂浓度下的胶团聚集数和胶团微极性.研究了链长变化对烷基苄基聚氧乙烯醚丙烷磺酸钠聚集性质的影响.考察了胶团聚集数的浓度效应,并由胶团聚集数与表面活性剂浓度关系方程外推求得了它们各自的临界胶束聚集数.     

稳态荧光猝灭法确定胶束聚集数的研究

选用芘作为荧光探针, 二苯酮作为猝灭剂, 以稳态荧光猝灭法测定了十二烷基硫酸钠、十二烷基磺酸钠和十六烷基三甲基演化铵的胶束聚集致, 并对其测定胶束聚集数方法的有效范围进行了讨论. 实验结果表明, 选择的探针-猝灭剂体系适用于稳态荧光猝灭法确定阴离子和阳离子表面活性剂的胶束浓度和聚集数.     

十六烷基二苯醚二磺酸钠分子有序聚集体的研究

采用芘为荧光探针、二苯甲酮为猝灭剂，以分子荧光探针法首次测定了由刚性基团联接的特殊双亲水基型阴离子表面活性剂——十六烷基二苯醚二磺酸钠(C16-MADS)的胶束聚集数(Nm)，并考察了表面活性剂浓度、无机盐浓度和温度对Nm的影响。结果表明，表面活性剂的浓度必须高于临界胶束浓度(cmc)一个数量级时，才能测定出较为合适的Nm；随着C16-MADS浓度的增大，Nm增大，胶束内核的微极性变小；而温度对Nm的影响极小。与传统的单亲水基阴离子表面活性剂相比，C16-MADS的有序聚集体表现出许多不同之处，如Nm仅为传统的单亲水基阴离子表面活性剂胶束聚集数的一半，无机盐浓度对Nm的影响极小，胶束内核的微极性明显增大。     

稳态荧光探针研究Guerbet醇聚氧乙烯醚羧酸钠的聚集行为

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合成的4种具有支链结构的Guerbet醇聚氧乙烯醚羧酸钠的临界胶束浓度和胶团的聚集数.结果表明,用稳态荧光探针法得到的临界胶束浓度(CMC)数值与表面张力法相差不大.结合临界胶束浓度、胶束微环境的极性和胶束聚集数的变化规律,推测了这类表面活性剂形成的胶束聚集体的结构形态.     

稳态荧光探针研究支链烷基苯磺酸钠的聚集行为

以芘为荧光探针、二苯酮为猝灭剂,用稳态荧光探针法测定了合成的4种带干扰基(磺酸基邻位的短链烷基)的支链烷基苯磺酸钠的临界胶团浓度、合适猝灭剂浓度下的胶团聚集数以及在不同浓度氯化钠水溶液中的胶团聚集数.结果表明,支链烷基苯磺酸钠分子中长链烷基碳数增加,临界胶团浓度大幅度降低,胶团聚集数减小;分子中短链烷基碳数增加,临界胶团浓度降低幅度小,胶团聚集数增大;胶团聚集数随氯化钠浓度增大而增大.     

荧光和动态光散射方法研究两性表面活性剂胶束的聚集和相互作用

以芘为荧光探针、二苯酮为猝灭剂,利用荧光方法测定了两性表面活性剂N-十二烷基-N,N-二甲基氨基丙磺酸盐(DDAPS)胶束在不同温度和不同NaCl浓度下的聚集数。利用动态光散射方法得到了胶束的水力半径Rh.结果表明,DDAPS的胶束聚集数和Rh值随NaCl浓度的升高略有增大;随温度的升高而稍有下降。DDAPS胶束之间的作用力以排斥力为主。     

磺酸基丙烯酸酯三元无规共聚物胶束的聚集行为

采用自由基溶液共聚合法,合成了系列磺酸基丙烯酸酯三元无规共聚物表面活性剂(APSA).利用FTIR、1H-NMR、13C-NMR、GPC及元素分析证实了APSA的结构及组成.APSA胶束为核壳结构,随磺酸基含量增加,亲水层增厚.低剪切速率下,APSA溶液的黏度随磺酸基含量的增加而增加,胶束间的相互作用增强,假塑行为增强;高剪切速率下,黏度基本保持一致.DLS和表面张力表明,APSA1可将水溶液的表面张力降至43.26 m N/m.随亲水基团增加,表面张力增加,临界胶束浓度(cmc)增加.溶液浓度在cmc以下时,光散射强度较低且变化缓慢,高于cmc后,光散射强度呈现急剧的线性增长趋势,胶束聚集数急剧增加.随溶液浓度和亲水基团增加,胶束尺寸和分布系数增加.荧光光谱表明,随APSA浓度增加,I1/I3值从1.8降低到约1.2,芘的(0,0)吸收峰从334 nm迁移到338 nm,I338/I334值从0.7增大到1.45,表明疏水基团聚集形成疏水微区,芘分子从水相极性环境转移到胶束疏水内核.随亲水基团含量增加,分子聚集形成胶束的难度增加,速率降低.     

荧光探针法研究新型Gemini表面活性剂在水溶液中的聚集行为

以芘为荧光探针、二苯酮为猝灭剂,用稳态荧光探针法测定了新型Gemini表面活性剂的临界胶团浓度(CMC)、胶团聚集数(N_agg)及胶团微极性.研究了Gemini表面活性剂结构和氯化钠浓度对CMC、N_agg、胶团微极性的影响.结果表明,新型Gemini表面活性剂的CMC比常规表面活性剂的CMC低1—2个数量级.当疏水基碳原子数增加时,CMC依次降低,N_agg增大,胶团微极性减小.当氯化钠浓度增大时,N_agg增大,胶团微极性减小.     

荧光和动态散射方法研究两性表面活性剂胶束的聚集和相互 …

以芘为荧光探针，二苯酮为猝灭剂，利用荧光方法测定了两性表面活性剂Ｎ十二烷基－Ｎ，Ｎ－二甲基氨基丙磺酸盐（ＤＤＡＰＳ）胶束在不同温度和不同ＮａＣｌ浓度下的聚集数，利用动态光莠射方法得到了胶束的水力半径Ｒｈ，结果表明，ＤＤＡＰＳ的胶束聚集数和Ｒｂ值随ＮａＣｌ浓度的升高略有增大，随温度的升高而稍有下降，ＤＤＡＰＳ胶束之间的作用力以排斥力为主。     

Self-assembly, hydration, and structures in N-decanoyl-N-methylglucamide aqueous solutions: effect of salt addition and temperature

The influence of NaCl addition and temperature on the self-assembly, hydration, and structures of N-decanoyl-N-methylglucamide (MEGA-10) in dilute solution has been investigated by using several experimental techniques, including tensiometry, steady-state fluorescence, density, viscosity, and static and dynamic light scattering. Tensiometry and fluorescence probe studies, by using pyrene as a probe, were used to obtain the critical micelle concentration (cmc) upon the electrolyte addition. The mean micellar aggregation numbers (N(agg)) as a function of the salt addition were obtained by both static light scattering and static quenching methods. The N(agg) values estimated by both methods were found to be in good agreement. It was found that the increase in the micelle size, produced by the addition of NaCl, is due to the increase in the aggregation number and in the amount of water non-specifically associated to the micelle. On the other hand, we have observed that the aggregation number remains invariant in the temperature range studied, whereas the hydrodynamic radius slightly decreases. The effect of electrolyte addition and temperature on the properties of MEGA-10 micelles is much less pronounced than those observed in the traditionally used POE-based surfactants.     

The unusual micelle micropolarity of partially fluorinated gemini surfactants sensed by pyrene fluorescence

New gemini surfactants having two fluorocarbon chains were prepared by refluxing partially fluorinated alkyl bromide with N,N,N',N'-tetramethyl-1,6-diaminohexane in acetonitrile. The partially fluorinated gemini surfactants containing a six-methylene spacer chain are easily soluble in water. The critical micelle concentrations (cmc's) were determined by various fluorescent probe methods. The hydrophobicity of a CF2 group was estimated to be 1.5 times that of a CH2 group according to the cmc values. The micelle micropolarity of a fluorocarbon gemini sensed by pyrene fluorescence was unusually high, suggesting an apparent iceberg-like environment in the location of pyrene. The significantly small micelle aggregation numbers of fluorinated gemini surfactants were ascertained by the pyrene fluorescence quenching method. The micelle ionization degree estimated by fluorescence quenching of 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ) gave tendencies similar to those of the corresponding hydrocarbon geminis.     

支链烷基苯磺酸钠聚集性质的实验与理论研究

以芘为探针、二苯酮为猝灭剂,用稳态荧光法测定了合成的4种链长分别为10、12、14、16碳,苯环均在β位取代的对烷基苯磺酸钠的临界胶团浓度、胶团聚集数和微极性.研究了链长对支链烷基苯磺酸钠聚集性质的影响.分析了支链烷基苯磺酸钠疏水、亲水基团对聚集性质的影响.用量子化学从头算Hartree Fock方法取6 31G 基组计算了支链烷基苯磺酸根离子气相中的电荷分布.     

稳态荧光探针法研究对-烷基-苄基聚氧乙烯醚羧酸甜菜碱的聚集行为

利用荧光探针法和表面张力法测定了一类疏水基中含有苯基的新型甜菜碱两性离子表面活性剂对-烷基-苄基聚氧乙烯醚羧酸甜菜碱(ABECB)的临界胶团浓度(cmc)、胶团微极性和表面张力(γ_cmc).研究结果表明,荧光探针(芘)法可用来测定这类表面活性剂的临界胶团浓度(cmc),且测定结果与表面张力法(吊片法)接近;ABECB具有较低的cmc和γ_cmc值,表明此类表面活性剂具有优良的表面活性; 胶团的微极性随着疏水链长的增大而略微减小,氧乙烯(EO)单元数的增大对ABECB胶团核内的微极性影响不明显.     

Adsorption and Micellization Properties of Novel Heterodouble‐Chained N‐Acyltaurate Surfactants

A set of heterodouble‐chained N‐acyltaurate surfactants (abbreviated as m+nP‐T, where m and n were carbon numbers of alkyl chain; P was phenyl; T was taurate) were synthesized. The novel amphiphiles contained sodium taurine as hydrophilic moiety and two different hydrocarbon chains as hydrophobic moiety. One was a long alkyl chain, and the other had an aromatic residue. Their surface properties were determined by Wilhelmy‐plate method, and micellization properties were investigated by fluorescence spectra of extrinsic probe and intrinsic probe. It was found that these surfactants showed some aberrant properties. It was difficult to obtain the equilibrium surface tension and critical micelle concentration (cmc) for the surfactants with two long chains. Pyrene was solubilized in micelle at concentration above cmc, and the fluorescent intensity ratio of the first vibronic peak (373 nm) to the third vibronic peak (383 nm) of pyrene decreased gradually. The aggregation number N, characterized by quenching the phenoxyl residue with methyl viologen (MV²⁺) as the extrinsic quencher, gradually increased with increasing surfactant concentration. These indicated that more and more molecules packed in a micelle with increasing concentration.     

稳态荧光探针法研究复配乳化剂的聚集行为

采用荧光探针技术,根据芘的第一振动峰I₁(373 nm)与第三振动峰I₃(384 nm)荧光强度的比值(I₁/I₃)随乳化剂浓度的变化,对十二烷基磺酸钠(AS)与壬基酚聚氧乙烯醚(Oπ-10)复配乳化剂的CMC值进行了测定,并与十二烷基磺酸钠(AS),壬基酚聚氧乙烯醚(Oπ-10)的CMC值进行了比较,结果表明复配乳化剂的CMC介于两者之间.以二苯甲酮为猝灭剂,用稳态荧光法测定了不同比例复配乳化剂的胶束聚集数,实验结果表明,复配乳化剂浓度为4—9倍CMC时,测定的胶束聚集数随复配乳化剂浓度的增大而线性增大;且Oπ-10:AS<2:1时,随着复合乳化剂中Oπ-10比例的增大,复配乳化剂胶束聚集数增大.利用芘的I₁/I₃值,结合胶束微环境的极性变化规律,探讨了复配乳化剂的聚集行为对硅丙乳液聚合物的影响.