核糖核酸酶A在丁酸十二铵—环己烷反胶束溶液中的催化动力学

研究了核糖核酸酶Ａ（ＲＮａｓｅＡ）在丁酸十二铵（ＤＡＢ）－环己烷反胶束溶液中催化水解胞苷２＇，３＇环单磷酸酯的动力学，数据符合Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ酶催化机理。以ｋｃａｔ／Ｋｍ表示酶催化活性时，ＲＮａｓｅＡ在反胶束溶液中的催化活性是在水溶液中的１４￣３０倍。无论是固定ＤＡＢ浓度还是固定Ｈ２Ｏ与ＤＡＢ浓度之比，随增溶水量的增加，ｋｃａｔ／Ｋｍ呈下降趋势。     

聚(丙烯酰胺-丙烯酸)/聚(丙烯酰胺-二甲基二烯丙基氯化铵)聚电解质复合溶液动态光散射研究

通过动态光散射、粘度和透光率测定，研究了聚（丙烯酰胺 丙烯酸）［Ｐ（ＡＭ ＡＡ）］／聚（丙烯酰胺 二甲基二烯丙基氯化铵）［Ｐ（ＡＭ ＤＭＤＡＡＣ）］聚电解质复合溶液的结构和性能．结果表明，Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径．Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）分子链间适度的库仑相互作用，可形成均相Ｐ（ＡＭ ＡＡ）／Ｐ（ＡＭ ＤＭＤＡＡＣ）聚电解质复合溶液，复合物具有较伸展的构象和较大的流体力学半径，因而溶液粘度较高．Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）分子链间过强的库仑相互作用或小分子电解质的屏蔽作用，可使复合物构象卷曲，结构紧缩，流体力学半径减小，甚至产生相分离，导致溶液粘度降低．     

聚（丙烯酰胺—丙烯酸）／聚（丙烯酰胺—二甲基二烯丙基氯化铵）聚电解质复…

通过动态光散射、粘度和透光率测定，研究了聚（丙烯酰胺－丙烯酸）［Ｐ（ＡＭ－ＡＡ）］／聚（丙烯酰胺－二甲基二烯丙基氯化铵）［Ｐ（ＡＭ－ＤＭＤＡＡＣ）］聚电解质复合溶液的结构和性能。结果表明，Ｐ（ＡＭ－ＡＡ）与Ｐ（ＡＭ－ＤＭＤＡＡＣ）复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径。Ｐ（ＡＭ－ＡＡ）与Ｐ（ＡＭ－ＤＭＤＡＡＣ）分子链间适度的库仑相互作用，可形成均相Ｐ（ＡＭ－ＡＡ）／Ｐ（Ａ     

脂肪酸十二烷基铵在四氯化碳中的聚集行为

通过碘光谱法和对水的增溶研究了乙酸十二烷基铵(DAA)、丙酸十二烷基铵(DAP)和丁酸十二烷基铵(DAB)在四氯化碳中的聚集作用; 碘光谱测得的(cmc)~I约比水增溶法测得的(cmc)~W低一个数量级。可能因为碘光谱法测得的是开始发生聚集时的cmc, 这时聚集体较小, 对水无增溶能力; 只有当聚集体随浓度升高而长大到一定程度时, 才能开始增溶水。实验表明, DAA, DAP和DAB的反胶束对水的饱和增溶能力, 分别相当于每一个表面活性分子增溶4.2, 9.4和13.5个水分子。根据球型反胶束模型, 计算了反胶束聚集数、捕集水团的半径和自由水团的半径。     

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．     

4-乙烯吡啶型聚皂与表面活性剂相互作用的研究

１实验部分１１试剂Ｎ－乙基聚４－乙烯吡啶溴化盐（ＱＰＶＰＥ）和Ｎ－十二烷基聚４－乙烯吡啶溴化盐（ＱＰＶＰＤ）是根据文献方法合成〔７〕,其中ＱＰＶＰＤ－２０、ＱＰＶＰＤ－３０分别表示溴十二烷与４－乙烯吡啶投料的物质的量比为２０％和３０％．ＳＤＳ（北京化工厂,分析纯）,ＢＤＤＡＣ（北京化工厂,分析纯）使用前未做进一步提纯．１２待测溶液的配制向５×１０－５ｍｏｌ／Ｌ的表面活性剂溶液（ＳＤＳ、ＢＤＤＡＣ）中,在缓慢搅拌下加入质量浓度为２５ｇ／Ｌ的ＱＰＶＰＥ和ＱＰＶＰＤ溶液,最后加入蒸馏水定容．温度保持在３０℃,溶液静置２４ｈ后进行测定．１３实验方法相对粘度采用乌氏粘度计在（３０±１）℃水浴中测定．ＱＰＶＰＥ、ＱＰＶＰＤ与ＳＤＳ混合溶液的可见光透射率采用７２１分光光度计在室温下测定．以质量浓度为５ｇ／Ｌ的聚合物溶液为参比,波长为４２０ｎｍ,比色皿厚度为１ｍｍ．采用ＤＤＳ－１２Ａ数字式电导率仪（电极为ＤＪＳ－１光亮电极）．温度补偿为２５℃．２结果与讨论ＱＰＶＰＤ分子链上的长链疏水烷基在水溶液中可聚集成胶束,形成紧缩构象,这种聚集体又称为疏水微区（Ｈｙｄｒｏｐｈｏｂｉｃｍｉｃｒｏｄｏｍａｉｎ）．同聚电解质类似,聚皂     

聚阳离子三甲基烯丙基氯化铵-丙烯酰胺共聚物的溶液性质研究

按实用要求对不同阳离子度及分子量的三甲基烯丙基氯化铵 丙烯酰胺共聚物Ｐ（ＴＭ ｃｏ ＡＡＭ）分别在水、水 甲醇、水 乙酸，不同浓度的ＮａＣｌ、ＫＣｌ、ＫＢｒ及Ｎａ２ＳＯ４水溶液中的溶液粘度行为进行了探讨，考察了低阳离子度的Ｐ（ＴＭ ｃｏ ＡＡＭ）的聚电解质行为及其大分子链在溶液中的分子链运动形态．     

二烷基磷（膦）酸钠盐萃取体系的相行为

用二烷基磷（膦）酸钠盐ＮａＡ作为阴离子表面活性剂，测定了ＮａＡ－醇－油－水体系Ｗ／Ｏ型微乳液中水的增溶量，用类三元相 图单相微乳区，测定了ＮａＤＴＭＰＰ－ＨＤＴＭＰＰ－煤油－水（含Ｎａ２ＳＯ４）体系相的变化，并讨论了溶剂、醇、温度、含盐量等对相行为的影响。     

DNA分子结构的多态性研究：（Ⅱ）吖啶橙凝聚体变化诱导的质粒DNA？…

利用吸收光谱和荧光光谱方法，研究了吖啶橙（ＡＯ）与质粒ＤＮＡ水溶液，以及含胶束介抽的吖啶橙与质粒ＤＮＡ溶液体系的相互结合作用及减色效应。结果表明：吖啶橙时质粒ＤＮＡ的吸收光谱有减色效应；含十二烷基硫酸钠（ＳＤＳ）的ＡＯ水溶液体中，随着ＳＤＳ浓度的增加，其光谱结果表明由凝聚态向单体的转化。而在含十二烷基硫酸钠（ＤＳ）的ＡＯ与质粒ＤＮＡ溶液体系中，吖啶橙凝聚态随ＳＤＳ浓度的增加，对ＡＯ与质粒ＤＮＡ相互     

反相悬浮与非均相水解法合成阴离子聚丙烯酰胺的研究

采用反相悬浮与非均相水解相结合的方法合成了分子量大于 １０７ 的阴离子聚丙烯酰胺（ＡＰＡＡ）。研究了水解度（ＨＤ）与水解时间及体系 叫的关系、不同水醇比（Ｖ＿水／Ｗ＿醇）条件下 ＨＤ与时间的关系，ＨＤ与温 度的关系，同时研究了ＡＰＡＡ在溶液中的粘性行为，讨论了分子量的 测定方法。     

电解质水溶液在丙酸十二铵-四氯化碳溶液中的增溶

表面活性剂在非极性溶剂中形成的反胶束在催化反应、光化学、蛋白质苹取分离等方面有着广泛的应用问．这些应用与反胶束的性质有着密切的关系，而增溶水后的反胶束其形状和大小都会发生很大的变化．增溶不同水量的反胶束的微极性、酸碱性、微勤度等已有不少文献报导［2－5］．一些不溶于非极性溶剂而溶于水的物质可以溶解在非极性溶剂中的反胶束核心水团中，这个现象被称为二次增溶．其中，电解质的二次增溶对于研究配体转换反应。酶催化反应问及改变反胶束内部的微环境有着十分重要的作用，Aebi和Weibush回首先研究了有水存在时N。CI在A…     

The effect of additives on the water solubilization capacity and conductivity in n-pentanol microemulsions

The influence of additives such as sodium salicylate and sodium chloride on the water solubilization capacity of AOT in n-pentanol solutions has been investigated. The water solubilization capacity is enhanced by sodium salicylate and decreased by sodium chloride. The percolation behavior of the water/AOT/n-pentanol system is studied by modifying the water concentration and temperature. No percolation threshold induced by water or temperature is detected either in the absence or in the presence of additives. The values of ln sigma have a linear correlation with temperature in the range of 5-40 degrees C. The activation energy is also estimated and discussed.     

A diffusive anomaly of water in aqueous sodium chloride solutions at low temperatures

Molecular dynamics simulations are presented for the self-diffusion coefficient of water in aqueous sodium chloride solutions. At temperatures above the freezing point of pure water, the self-diffusion coefficient is a monotonically decreasing function of salt concentration. Below the freezing point of pure water, however, the self-diffusion coefficient is a non-monotonic function of salt concentration, showing a maximum at approximately one molal salt. This suggests that sodium chloride, which is considered a structure-making salt at room temperature, becomes a structure-breaking salt at low temperatures. A qualitative understanding of this effect can be obtained by considering the effect of ions on the residence time of water molecules near other water molecules. A consideration of the freezing point depression of aqueous sodium chloride solutions suggests that the self-diffusion coefficient of water in supercooled sodium chloride solutions is always higher than that in pure (supercooled) water at the same temperature.     

Effects of Mixed Anionic-Cationic Surfactants and Alcohol on Solubilization of Water-in-oil Microemulsions

The solubilization of water in w/o microemulsions formed with mixed-surfactants containing one anionic and one cationic surfactant and alcohol was studied as a function of alkyl chain length of oil (C6 to C16), mixed-surfactant (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB, or cetylpyridinium bromide CPB), and alcohol (1-butanol, 1-pentanol, 1-hexanol). The results show that the solubilization of water in microemulsion systems increases significantly with the mixed-surfactants due to the synergistic effect resulting from the strong Coulombic interactions between cationic and anionic surfactants and the solubilizing efficiency increases as the chain length or concentration of alcohol increases. With increasing the oil chain length the solubilization for water increases, decreases, and has the chain length compatibility effect when the systems contain 1-hexanol, 1-butanol, 1-pentanol, respectively. The total solubilizing capacity increases as the surfactant concentration (keep the ratio of SDS to butanol constant) increases.     

Solubilization in alkanes by alcohols as reverse hydrotropes or "lipotropes"

Hydrotropes in aqueous systems do not aggregate in micelles, inhibit presence of mesophases and allow significant and progressive solubilization of "insoluble" molecules in water. It was shown that n-alcohols in alkanes develop the same properties, including the power-law for maximum solubilization of "hydrophilic" molecules. The aim of this paper is to highlight properties of reverse hydrotropes or "lipotropes" by taking n-alcohol/alkane mixtures as model systems. So as to establish a clear parallel between lipotropes and hydrotropes the same methodology used to characterize hydrotropes was applied to these systems. The solubilization of solutes insoluble in alkane, i.e. water and a hydrophilic dye in dodecane, enabled by the addition of n-alcohols ( n = 2, 3, 4 and 7) was studied. In parallel, the nonmicellar aggregation state of butan-1-ol and heptan-1-ol in dodecane was investigated by small-angle X-ray scattering. By applying the Porod's treatment the specific area of the H-bond network formed by heptan-1-ol and the area occupied by hydroxyl group in this network were determined as a function of concentration. A correlation between the aggregation of alcohols in dodecane and the solubilization was made. The disrupting of concentrated mesophases by a lipotrope was illustrated by studying the effect of adding n-alcohols to water/oil/extractant ternary systems used in liquid/liquid extraction. Under some conditions the organic phase splits up into two phases: an extractant mesophase and nearly pure oil. The amount of n-alcohols required to make the extractant mesophase disappear was determined for water/alkane/malonamide extractant systems. The influence of the chain length of the n-alcohol on the efficiency as lipotrope was also experimentally studied. The trend obtained was similar to the one observed with the solubilization experiments.     

Clouding behavior of nonionic–cationic and nonionic–anionic mixed surfactant systems in presence of carboxylic acids and their sodium salts

The study is focused on evaluation of clouding phenomena of the aqueous single nonionic surfactant system Triton X-100 (TX-100) and its mixed systems with anionic aerosol-OT (AOT) and cationic dodecylpyridinium chloride (DPC) in presence of hydrophobic ions furnished by sodium salts of carboxylic acids, viz., sodium ethanoate, sodium propanoate, sodium butanoate, and sodium hexanoate and the respective carboxylic acids [ethanoic acid, propanoic acid, butanoic acid, and hexanoic acid]. The influence of salts on the cloud point (CP) has been explained on the basis of salt effect as well as the solubilization of higher alkyl chain hydrophobic ions furnished by these salts. Moreover, the co- and counterion effect has been taken into account to explain the variation of the CP in the mixed systems. However, the effect of acids on CP has been explained in the light of their aqueous solubility and their partitioning ability between octanol and water as reflected by their K _OW values.     

Solubilization of n-alkylbenzenes in aggregates of sodium dodecyl sulfate and a cationic polymer of high charge density (II)

The solubilization property of the aggregate composed of sodium dodecyl sulfate (SDS) and a cationic polymer (polydiallyldimethylammonium chloride, PDADMAC) was investigated. From the binding isotherm, the increasing free SDS concentration (Cf) above the critical aggregation concentration (cac) was clearly confirmed and used to calculate the Gibbs free energy change of solubilization. The maximum additive concentration of the alkylbenzene solubilizates remained almost constant around their aqueous solubilities below the cac and then increased with increasing SDS concentration above the cac and with decreasing alkyl chain length of the solubilizates. Also, their solubility increased with increasing temperature over the concentration range of the surfactant examined. Because the monomeric DS- concentration in the aqueous phase (Cf) increased with the SDS concentration above the cac in the SDS/PDADMAC system, Cf was evaluated from the binding isotherm to calculate the change in the Gibbs energies of transfer of the solubilizates using the phase separation model. The Gibbs energy change for the solubilizates decreased with increasing temperature and increasing alkyl chain length. The decrease in the Gibbs energy per CH2 group (DeltaGCH2 degrees) was favored by an increase of temperature, and it was larger in magnitude than that for micelles of single-surfactant systems. From the values of DeltaH degrees and TDeltaS degrees, the solubilization of alkylbenzenes into SDS/PDADMAC was found to be entropy-driven.     

Micellar solubilization thermodynamics of acetophenone in surfactant mixtures: Case of benzyldimethyltetradecylammonium chloride and trimethyltetradecylammonium chloride

The thermodynamics of micellar solubilization of acetophenone in mixtures of two cationic surfactants [benzyldimethyltetradecylammonium chloride +trimethyltetradecylammonium chloride] has been derived from calorimetric measurements at controlled solute activity. The partition coefficient between micelles and water as well as the standard enthalpy and entropy of transfer between micelles and water were calculated. The results were compared to the case of benzylalcohol in the same cationic mixtures. For acetophenone, the variation of all thermodynamic transfer functions with micellar composition may be described by the regular solution formalism. The same conclusion has been achieved for most polar solutes in various surfactant mixtures: favorable interaction between unlike surfactants induces an unfavorable micellar solubilization. Exceptions should be found with the cases where solute solubilization induces profound micellar changes. It seems to be the case with some alcohols in the cationic surfactant mixtures studied.     

The effect of structural variation of alcohols on water solubilization in nonionic microemulsions 1. From linear to branched amphiphiles--general considerations

This article is the first part of a two-part study that exemplifies how to treat the solubilization of water in multicomponent surfactant-based systems. In particular, it aims at clarifying the role of cosurfactants in water solubilization in these systems. The judicious selection of the components in such systems to maximize water solubilization is occasionally thought to be dictated by the chain length compatibility principle, which may be expressed quantitatively by the BSO (Bansal, Shah, O'Connell) equation. Here we demonstrate some limitations of the equation. For example, in our best model system, C12(EO)8/dodecane+pentanol=1:1 (by weight)/water at 27+/-0.2 degrees C, the BSO equation predicts that no alcohol is needed for maximum water solubilization, contrary to our experimental findings. We discuss how to optimize the alcohol/oil weight ratio needed for stabilizing four-component microemulsions. In our model systems C12(EO)8 or C(18:1)(EO)10/pentanol/dodecane/water, this optimal weight ratio is 1:1. We also highlight the difference between the effect of normal alcohols on water solubilization-which passes via a maximum-and their effect on percolation processes and structured changes of proteins, which depends solely upon the alcohol hydrophobicity. For the investigation of the effect of branching on phase behavior the utilization of an extended form of the geometrical branching factor F(b) is suggested. The meaning of this factor is elucidated by comparing it with topological indices.