单分子链胶束的胶束化行为与相关新概念的提出

采用水溶液均聚合方法,制备了阳离子型表面活性单体（2-丙烯酰胺基）乙基十四烷基二甲基溴化铵（AMC14AB）的均聚物,使用荧光探针法、表面张力测定及电导测定法,重点考察了均聚物P（AMC14AB）在水溶液中的胶束化行为与表面吸附现象．在水溶液中,均聚物P（AMC14AB）呈现单分子链胶束的聚集形态,具有零临界胶束浓度（CMC=0）,从开始加入P（AMC14AB）起,水溶液中随即产生单分子链胶束,不存在Krafft温度．P（AMC14AB）在溶液表面也发生表面吸附,使水的表面张力下降,即P（AMC14AB）也具有表面活性;随着浓度增大,表面吸附量增大,水的表面张力持续下降;当表面吸附达到饱和时,表面张力一浓度曲线上出现突变点,该点应该定义为饱和的表面吸附浓度（SSAC）,而不应该再称为临界胶束浓度．P（AMC14AB）单分子链胶束溶液对疏水有机物（甲苯）的增溶情况,明显不同于普通小分子表面活性剂十六烷基二甲基溴化铵（CTAB）的多分子胶束溶液,甲苯增溶量-P（AMC14AB）浓度的关系曲线上无突变点,而且对甲苯的增溶能力高于CTAB的多分子胶束溶液．     

番红花红T与表面活性剂的作用及其在标记DNA中的应用

对阳离子染料番红花红Ｔ（ＳＴ）在阴离子表面活性剂存在时的溶液状态的吸收光谱和荧光光谱进行了研究。结果表明，低浓度阴离子表面活性剂与ＳＴ形成缔合物，导致ＳＴ的吸收与荧光强度降低；增大表面活性剂的浓度，其分子胶束前预聚集促使染料形成非荧光二聚体，导致荧光急剧猝灭，吸收光谱出现新的特征吸收峰；当表面活性剂浓度大于临界胶束浓度（ＣＭＣ）时，染料二聚体离解，ＳＴ单体增溶于胶团中形成新的高量子产率荧光体。本文     

1-(4-磺酸基苯基)-3-[4-(苯基偶氮)苯基]-三氮烯与季铵盐型阳离子表面活性剂的显色反应及应用

合成了１－（４－磺酸基苯基）－３－［４－（苯基偶氮）苯基］－三氮烯（ＳＰＡＰＴ）,研究了该试剂在强碱性介质中与季铵盐型阳离子表面活性剂溴化十六烷基吡啶（ＣＰＢ）和溴化十六烷基三甲铵（ＣＴＭＡＢ）的显色反应体系,试剂与表面活性剂形成１∶３的紫红色离子缔合物,其表观摩尔吸光系数分别为１．６７×１０４和１．０６×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。测定了显色体系中ＣＰＢ和ＣＴＭＡＢ的临界胶束浓度（ＣＭＣ）,证明在比尔定律范围内,ＣＰＢ和ＣＴＭＡＢ均以单分子缔合显色。确定了显色体系最佳实验条件     

十四烷基芳基磺酸盐形成的分子有序组合体

以表面张力法、碘光谱法、水增溶法和相态图法研究了自制的三种十四烷基芳基磺酸盐在不同条件下形成的分子有序组合体(胶束、反胶束和微乳液),并考察了分子结构、溶剂、无机盐和短链醇等对其的影响.结果表明:增加十四烷基芳基磺酸盐分子亲油基支化度,不利于其在水溶液或混合极性溶剂(乙二醇-水)中形成胶束而有利于其在非极性溶剂正庚烷中形成反胶束;溶剂极性的降低,促使表面活性剂溶液由胶束溶液→单体溶液→反胶束溶液转变;无机盐或短链醇的加入促进了水溶液中胶束的形成,且反离子价态数或醇烷基碳原子数越大,越有利于胶束形成;无机盐浓度的增加导致表面活性剂/正丁醇/正辛烷/NaCl/水形成的微乳液体系在一定温度下发生由WinsorI→WinsorIII→WinsorII型的转变.     

混合反胶束的电导与微结构研究

反胶束是两亲分子在非极性溶剂中形成的一种有序组合体，在医药、化工、采油、胶束催化及酶催化等领域中有重要应用．与胶束溶液相比，人们对反胶束的形成与结构的了解至今仍不充分．特别是对于由混合表面活性剂形成的反胶束的研究几乎无人涉及．本文采用动态光散射、电导及荧光光谱等手段对阴离子表面活性剂AOT与非离子表面活性剂形成的混合反胶束进行了研究，旨在探讨利用表面活性剂的复配来调节和控制反胶束的结构和性能．亚实验部分二异辛基磺化琉璃酸钠（AOT，Sigma公司）；Brij30为含4个氧乙烯基（EO基）的十二碳醇（AcrosOrgani…     

LSmn系列表面化学性质与胶束化作用

通过表面张力的测定, 研究了十二烷基聚氧乙烯聚氧丙烯醚(LSmn)系列表面活性剂LS36、LS45、LS54在溶液表面吸附和形成胶束的热力学函数随温度的变化. 给出了它们在水溶液中的二组分相图.结果表明, LS36、LS45、LS54的表面活性都较高. 在25～50 ℃范围内, 临界胶束浓度(cmc)和平衡表面张力分别在4.44×10－6～17.3×10－6 mol•L－1和30.1～33.5 mN•m－1之间, 表面吸附和形成胶束的自由能分别在－40.0～－49.5 kJ•mol－1和－27.2～－33.1 kJ•mol－1之间.不论是在溶液表面吸附还是形成胶束均为熵驱动过程.其中LS36由于含具有亲水能力较强的聚氧乙烯基团(EO)成分较低, 因此不论其浊点还是其表面吸附和形成胶束的热力学函数均与LS45、LS54具有较大差异.     

离子液体表面活性剂1-丁基-3-甲基咪唑烷基硫酸酯的合成及其在水溶液中的聚集行为

采用离子交换法,由1-丁基-3甲基咪唑氯盐（C4mimCl）和烷基硫酸钠合成了一系列无卤素的阴离子表面活性离子液体—1-丁基-3-甲基咪唑烷基硫酸酯[C4mim][CnH2n 1SO4](n=8,12,16),利用表面张力仪、稳态荧光光谱等手段考察了表面活性离子液体在水溶液表面及体相中的聚集行为,结果表明,与传统无机反离子相比,有机咪唑阳离子[C4mim] 作为反离子的离子液体型表面活性剂具有较高的表面活性,[C4mim] 产生的氢键引起的抑制分子规则排列的作用小于其促进分子有序排列的疏水作用。长烷基链的阴离子是界面膜及胶束的主要组成成分,阴离子疏水烷基碳链的增长虽然可促进胶束的形成,但却在一定程度上抑制[C4mim] 离子参与界面或胶束的形成;阴离子所带烷基链越长,越不利于阳离子[C4mim]＋参与界面膜或胶束的形成,界面膜或胶束中表面活性剂排布越松散,即界面张力越大,体系中胶束聚集数较小。     

PVP与C~1~4BE之间的相互作用

通过表面张力和胶束聚集数的测定,研究了聚乙烯吡咯烷酮(PVP)与两性表面活性剂十四烷基甜菜碱(C~1~4BE)之间的相互作用。结果表明,PVP与C~1~4BE可通过其分子间的疏水作用和极性基团间的静电力形成PVP大分子/表面活性剂聚集体。因此,混合溶液的表面张力-浓度曲线表现出两个转折点,C~1~4BE的胶束聚集数随PVP浓度增大而减小。     

表面活性剂与聚合物相互作用的动力学模拟

用扩散颗粒动力学模拟方法（Dissipative Particle Dynamics，DPD）模拟了 中性聚合物与离子型表面活性剂的相互作用。在分子水平上研究了介于微观和宏观 上的一些性质，直观地用三维图形描绘了聚合物在表面活性剂溶液中的聚集形成， 并通过聚合物的末端的变化表征了聚集过程。结果发现：随着表面活性剂浓度的增 加，聚合物呈现自由伸缩→形成松散的棒状结构→再出现胶束状珍珠链结构→最终 在六角状和层状相中分布的过程。DPD模拟方法能够直观地得到聚合物在表面活性 剂溶液中的聚集形态。     

光敏型季铵盐类阳离子表面活性剂的合成及表面活性和泡沫性质

本文报道了一种光敏型的阳离子表面活性剂（AZO），其分子结构中含有偶氮苯基团，并研究了光照对表面活性和泡沫性能的影响。经紫外光照射后，表面活性剂的饱和吸附量（Г_max）减小，临界胶束浓度（cmc）、最低表面张力（γ_cmc）和分子极限占有面积（A_min）增大；气泡数目增多，直径变小，发泡能力和泡沫稳定性降低。实验结果证实，该表面活性剂的表面活性和泡沫稳定性可以用光照进行调控。     

Thermodynamic Characteristics of Micellization in the Droplet Model of Surfactant Spherical Molecular Aggregate

The dependence of the work of the molecular aggregate formation on the aggregation number and surfactant monomer concentration in solution that has the key role for the theory of micellization was studied on the basis of a simple realistic droplet model of spherical aggregate composed of surfactant molecules (the o/w micelle type). Analytical formulas were derived for the coordinates of maximum and minimum of aggregate formation work on the aggregation number axis arising with an increase in the concentration of micellar solution. Model calculations of the thermodynamic characteristics of the kinetics of micellization were performed for premicellar and micellar regions of aggregate sizes within a wide range of solution concentration including the critical micellization concentration.     

Defining the different phases of premicellar aggregation using the photophysical changes of a surface-probing compound

Photophysical changes of a cylindrical compound undergoing twisted intramolecular charge transfer may be used as a surface probe to study the different phases of premicellar aggregate formation. The probe molecule, trans-2-[4-(dimethylamino)styryl] benzothiazole (DMASBT), attaches itself to the premicellar and the micellar aggregates of cationic, anionic, and neutral surfactants in different orientations because of its dipolar nature in the excited state. The micelle formation is preceded by a few typical rearrangements of the surfactant molecules. These events need proper inspection that can only be done by compounds that sense environmental changes by residing in the vicinity of the surface of those aggregates. Steady-state and time-resolved fluorescence spectroscopy coupled with steady-state fluorescence anisotropy measurements serve as a very useful tool to monitor premicellar aggregate formation. The dipolar interaction of DMASBT with the surface of the aggregate and its extraordinary capability to sense the polarity of the environment make it a very efficient molecule to use for the purpose.     

Micellar Catalysis of Composite Reactions—The Effect of SDS Micelles and Premicelles on the Alkaline Fading of Crystal Violet and Malachite Green

ABSTRACT

The effect of SDS micelles and premicelles on the reversible alkaline fading reactions of crystal violet and malachite green were studied. Micellar and premicellar catalysis models for 1-1 type reversible reactions were proposed. The rate constants of forward and backward reactions and equilibrium constants of these reversible alkaline fading reactions in SDS micellar solutions were obtained from a micellar catalytic model. Under the premicellar condition the average number of SDS molecules per substrate molecule with n surfactant molecules was obtained from a premicellar catalytic model. The results indicated that both SDS micelles and premicelles exhibited an inhibiting effect on the forward reaction, while they exhibited an accelerating effect on the backward reaction. These results can reasonably be accounted for in terms of electrostatic interactions.     

Emission behavior of 1-methylaminopyrene in aqueous solution of anionic surfactants

A new fluorescent probe, methylamino derivative of pyrene, has been considered to characterize the concentration dependent emission behavior of an aqueous solution of anionic surfactants, viz., SDS, DSS, and SDBS. It was found that the emission of the probe is uniquely sensitive to the changes in surfactant (anionic) concentration due to the functional group effect of the probe over the parent moiety, pyrene. Here, 1-methylaminopyrene (MAP) showed significant quenching of emission well below the critical micellar concentration (cmc) of the surfactant. Excimer emission of the probe due to the formation of premicellar aggregates of the surfactant solutions at a concentration close to but below the cmc and again an enhanced emission of the probe above the cmc were observed as a consequence of definite MAP-surfactant interactions. These observations assisted the possible quantification ofsurfactant concentrations and their chain length dependent premicellar aggregate formations. Significant monomer emission in relation to probe distribution in micelle was analytically authenticated. Dynamic light scattering (DLS) studies revealed the incorporation of the probe molecules in the micellar core. The fluorophore emission showed nonlinear behavior when the surfactant concentration was far above the cmc. Abrupt changes in the emission characteristics in relation to the micellar concentration led to the determination of the cmc of the surfactants.     

The Stage of Ultrafast Relaxation in Micellar Surfactant Solutions

The Becker–Döring kinetic equations are employed to describe the stage of ultrafast relaxation in micellar surfactant solutions, which ends in the establishment of a quasi-equilibrium distribution in the premicellar region of aggregate sizes. This is performed by analyzing the spectrum of the eigenvalues of the matrix of kinetic coefficients of the linearized Becker–Döring difference equations, which describes the complete multistage relaxation in a micellar system. The first value of the spectrum ordered as an ascending series is equal to zero (infinite relaxation time), thereby corresponding to the law of conservation of the surfactant quantity. The second value is very small; it differs from the series of subsequent values by several orders of magnitude and determines the time of slow relaxation. The other eigenvalues describe the processes of fast relaxation and comprise the contributions from the relaxation processes in both micellar and premicellar regions of aggregate sizes. In the latter region of the spectrum, the contribution of the ultrafast relaxation can be numerically distinguished. The obtained result is confirmed by the analysis of the spectrum of relaxation times of premicellar aggregates, which are considered as a closed system. It is also shown that the spectrum of ultrafast relaxation times is mainly determined by the first diagonal elements of the matrix of the linearized Becker–Döring equations and can be described analytically.     

利用光化学探针技术研究长链烷烃硫酸钠水溶液中预胶束的生成

罗丹明6G与罗丹明B之间的能量转移和吖啶橙形成聚态的现象用于研究长链烷基硫酸钠(C~nH~2~n~+~1OSO~3Na,n=12,14和16)在水溶液中预胶束的生成。结果表明,烷基链的长度影响这些表面活性剂形成预胶束的能力,碳数的增加使预胶束形成浓度降低。     

Dependence of the solubility of atmospheric oxygen in weakly alkaline aqueous solutions on surfactant concentration

The solubility of atmospheric oxygen in solutions of surfactants of different natures at 293 K and pH 8 is determined by gas chromatography. It is found that additives of nonionic surfactants decrease the oxygen content in the solution in the premicellar region and increase its solubility in the micellar region. It is shown that, for anionic surfactants, a decrease in the solubility of O₂ is observed over the entire concentration range.     

SDS胶束对孔雀绿褪色反应的影响

研究了十二烷基硫酸钠（SDS）表而活性剂胶束和预胶束对孔雀绿褪色可逆反应的影响，建立了1－1型可逆反应的胶束催化模型和预胶束催化模型，获得了胶束相中正逆反应的速率常数和预胶束的平均聚集数．结果表明，SDS胶束和预胶束对正反应有禁阻作用，而对逆反应有催化作用．     

Critical Micellization Concentration of Ionic Surfactants: Comparison of Theoretical and Experimental Results

Theoretically calculated critical micellization concentration (CMC) of an ionic surfactant and the corresponding experimental value (CMC₀) are compared. The CMC values are calculated within the framework of the quasi-chemical model. The CMC₀ values are determined by the extrapolation of two linear parts of a dependence of a solution property on surfactant overall concentration. These parts of the aforementioned dependences correspond to the premicellar and micellar regions. The difference between CMC and CMC₀ is found to be negligible and comparable with the measurement error. Cases in which this difference must be taken into account when estimating the properties of micellar solutions are discussed. It is shown that the micellization constant K _c of surfactant molecules can be calculated from the data on CMC₀.     

Molecular dynamics study of the structure and mechanism of formation of molecular associates in aqueous solutions of surfactants

The process of micelle formation in an aqueous solution of the surfactant was simulated by the computer experiment. It was established by the molecular dynamics method that micelles are formed through the formation of premicellar associates of the surfactant. The practical absence of an attraction between single molecules of sodium pentadecyl sulfonate (SPDS) and premicellar associates dissolved in water was shown for a SPDS—water system. The function of the radial distribution of Na⁺ counterions towards polar groups of SPDS molecules in water and on the surfaces of micelles and premicellar associates was studied by the molecular dynamics method. The presence of dissociated and non-dissociated polar groups of the SPDS molecular on the micelle surface was found. The data obtained are consistent with the existence concepts on micelle formation processes.