聚(偏氯乙烯-丙烯酸甲酯)-b-聚丙烯酸嵌段共聚物的胶束化行为

通过可逆加成-断裂链转移(RAFT)溶液聚合制备了不同组成的两亲性聚(偏氯乙烯-丙烯酸甲酯)-b-聚丙烯酸(PVDC-b-PAA)嵌段共聚物,采用动态光散射、表面张力仪和透射电镜等研究了PVDC-b-PAA共聚物在水溶液中的胶束化行为,结果表明采用N,N-二甲基甲酰胺溶解、水相渗析可实现PVDC-b-PAA共聚物的自组装,形成均一透明的胶束水溶液;随着亲水PAA嵌段含量的增加,PVDC-b-PAA共聚物的临界胶束浓度逐渐增大;PVDC-b-PAA共聚物自组装形成的胶束呈现典型的球状结构,胶束粒径在70.9~110.9 nm之间,粒径分布较窄;水相p H值影响PVDC-b-PAA共聚物胶束表面zeta电位及胶束的聚集行为,当水相p H值由3变为1,胶束表面由带负电荷变为带正电荷,胶束聚集程度和聚集体平均粒径显著增大,粒径分布变宽.     

阴离子型胶束液相色谱的溶质保留行为

以SDS阴离子表面活性剂作流动相,酸性、中性及两性药物为受试药物,运用三相平衡理论考察影响阴离子型胶束液相色谱（AMLC）溶质保留行为的几个因素。保留由溶质与胶束相及修饰后固定相的综合作用决定。有机调节剂正丙醇的加入改变了溶质从水相到固定相或到胶束相的平衡,保留取决于溶质疏水性和静电性间的平衡。此外对羟基苯甲酸酯类同系物的亲脂性与3种细菌最小抑菌浓度具有显著相关性,提示其抑菌机理主要取决于药物与生物膜的亲和性。     

DTAB-月桂酸钠体系表面活性剂双水相研究

绘制和分析了十二烷基三甲基溴化铵（DTAB） 月桂酸钠（SL）组成的表面活性剂混合体系相图,系统研究了温度和无机盐等因素对该体系表面活性剂双水相 (ASTP) 影响的规律性.结果表明:与富含负离子表面活性剂双水相 (ASTP A) 相比较,富含正离子表面活性剂双水相(ASTP C)区域更大、更稳定;温度升高,无机盐(NaBr)的浓度增大,都引起 ASTP 体系上相体积的减小和下相体积的增加;囊泡普遍存在于ASTP的上下相之中.     

表面活性剂双水相的性质及其应用 Ⅰ. 表面活性剂双水相的微环境性质

阴、阳离子表面活性剂混合体系, 在一定浓度及混合比范围内, 可以形成两个互不相溶、平衡共存的水相, 称为表面活性剂双水相。其中阳离子表面活性剂过量的双水相体系, 称为阳离子双水相。本文分别以芘和罗丹明B作为探针, 用荧光探针法研究了摩尔比为1.6:1的C12NE和SDS混合体系成形成的阳离子双水相,测定其上层和下层的胶束微环境的极性和微粘度, 取得了有意义的结果。     

SDS对PEO-PPO-PEO嵌段共聚物溶液行为的影响

对PEO-PPO-PEO（127）三嵌段共聚物的水溶液行为及添加十二烷基硫酸钠（SDS）后对共聚物溶液行为的影响进行了研究．利用荧光探针技术对不同SDS浓度下F127／SDS体系的胶来形成进行研究,并研究了SDS对F127浓溶液凝胶化行为的影响．结果表明：随着SDS浓度的增大,F127稀溶液胶束的形成受到抑制,SDS浓度愈大,形成的胶束结构就愈疏松．对F127浓溶液来说,SDS与F127摩尔比小于2时,体系易于凝胶化;但当SDS浓度增大,其与F127摩尔比大于2时,体系开始难于凝胶化,直至摩尔比大于5时,体系不再形成凝胶．     

表面活性剂双水相的性质及其应用 Ⅰ. 表面活性剂双水相的微环境性质

阴、阳离子表面活性剂混合体系，在一定浓度及混合比范围内，可以形成两个互不相溶、平衡共存的水相，称为表面活性剂双水相．其中阳离子表面活性剂过量的双水相体系，称为阳离子双水相．本文分别以芘和罗丹明B作为探针，用荧光探针法研究了摩尔比为1：6：1的C_12NE和SDS混合体系所形成的阳离子双水相，测定其上层和下层的胶束微环境的极性和微粘度，取得了有意义的结果．     

四-(4-苯基磺酸基)卟啉在反相微乳内相中的聚集行为

本文系统研究了四-(4-苯基磺酸基)卟啉(TPPS)在由聚乙二醇辛基苯基醚（TX-100）构筑的反相微乳液内相中的聚集行为。通过改变反相微乳水相液滴的pH值、粒径及TPPS的浓度,发现在反相乳液内相中TPPS的表观pKa明显小于在水溶液中的pKa（4.9）,并且,TPPS的表观pKa随着水相液滴粒径的减小而降低;当水相液滴的pH > pKa时,TPPS以去质子化单体H2TPPS4-形式存在,而当pH < pKa时,TPPS以质子化单体H4TPPS2-和J-聚集两种形式存在,并且TPPS浓度的增大,促进了H4TPPS2-向J-聚集转变;在pH值不变的条件下,随着水相液滴粒径的增大,TPPS的存在状态由H2TPPS4-向H4TPPS2-转变,并形成J-聚集。     

二苯胺重氮盐,重氮树脂与表面活性剂的相互作用及基于重氮树脂的超薄感光膜的研究

重氮树脂(DR)是二苯胺-4-重氮盐(DDS)与甲醛的缩合产物,它是最重要的阴图胶印版的感光剂.DR和DDS的缺点是热稳定性差,特别是在水中.本论文第一部分内容是关于DDS和DR与表面活性剂相互作用的研究.研究结果表明:DR和DDS的热稳定性在阴离子表面活性剂十二烷基硫酸钠(SDS)水溶液中得到显著提高.原因是DDS和DR分子与SDS分子间的疏水相互作用和静电吸引作用使它们可以进入SDS的胶束相,同SDS分子共同形成混合胶束.所以DR和DDS在S DS水溶液中存在胶束相和水相的分配平衡.处于胶束相的DDS或DR,由于胶束的静电及极性效应使它们的重氮基得到保护.进入胶束相的DDS和DR的量越多,它们水溶液的热稳定性提高越显著.由于DDS和DR与SDS间较强的相互作用使SDS浓度(≈10-5mol/L)在远低于临界胶束浓度(8×10-3mol/L)时形成了混合预胶束,预胶束对DDS和DR同样具有保护作用.     

激光光散射和电子自旋共振技术研究十二烷基硫酸钠与聚乙烯吡咯烷酮的相互作用

应用动态激光光散射(DLS)和电子自旋共振(ESR)测定研究了单长链表面活性剂十二烷基硫酸钠(SDS)与聚乙烯吡咯烷酮(PVP)相互作用.DLS测定结果表明:SDS在水中形成动力学半径约为61 nm的胶束聚集体,PVP在水中卷曲成动力学半径约为12 nm的线圈,DLS确定的SDS临界胶束浓度(cmc)为6.4×10^-3 mol·L^-1, PVP-SDS具有强的相互作用,PVP分子缠绕在SDS胶束聚集体的周围,屏蔽了SDS胶束聚集体表面碳氢基团与连续水相的接触;ESR结果表明:自由基探针5-doxyl stearic acid在SDS形成胶束聚集体后,从一个较强极性的连续相转变到较小极性的胶束聚集体内核中,胶束聚集体内核的微粘度较纯水的大,SDS与PVP复合聚集体的微观粘度较SDS胶束溶液的大,ESR确定SDS的cmc为6.8×10^-3 mol·L^-1.     

β-CD对SDS胶束生成与特性的影响

通过胶束的扩散系数D、聚集数N和β-CD在SDS胶束与水连续相间的分配系数P的测定,研究了β-CD对SDS胶束特性的影响.结果表明,β-CD浓度较小时,随着β-CD的加入,其在SDS胶束相中的分配增大,胶束的扩散系数D与聚集数N均降低.β-CD浓度较大时,其在水连续相中的分配增加,对SDS胶束的扩散系数D与聚集数N的影响显著降低.SDS浓度小于第一CMC,β-CD与SDS单体形成1∶1的包合物;SDS浓度大于第一CMC,β-CD与SDS形成1:8的混合球形胶束.     

Protein partitioning in thermoseparating systems of a charged hydrophobically modified ethylene oxide polymer

The phase behavior of a thermoseparating cationic hydrophobically modified ethylene oxide polymer (HM-EO) containing tertiary amines has been investigated at different pH, salt and sodium dodecyl sulfate (SDS) concentrations, in order to find a water/HM-EO two-phase system suitable for protein partitioning. The used polymer forms micellar aggregates that can be charged. By changing pH and SDS concentrations the netcharge of the SDS/HM-EO aggregate can be shifted from positive to negative. Bovine serum albumin (BSA) and lysozyme were partitioned in the thermoseparated two-phase systems of the cationic polymer at different pH, salt and SDS concentrations. The dominant attractive interactions between the polymer aggregates and the studied proteins were shown to be of electrostatic (Coulomb) nature rather than hydrophobic interaction. At low ionic strength the positively charged polymeric aggregates attracted negatively charged BSA and repelled positively charged lysozyme. Upon addition of SDS the negatively charged aggregates attracted lysozyme and repelled BSA. Thus, it was possible to direct proteins with different charges to the polymeric phase and redirect them to a polymer-depleted phase by changing the netcharge of the polymeric aggregates. The effect of different salts on the partitioning of BSA in a system of slightly positively charged HM-EO was studied. NaCl and KBr have a significant effect on driving the BSA to the polymer-depleted phase, whereas KF and K2SO4 have a smaller effect on the partitioning. The cloud point temperature of the charged polymer decreased upon addition of SDS near the isoelectric molar ratio of SDS to polymer and also upon salt addition. In the latter case the decrease was smaller than expected from model calculations based on Flory-Huggins theory, which were performed for a charged thermoseparating polymer at different charges and salt concentrations.     

胶束溶液体系对毛细管电动色谱酸性化合物分离的影响

以阴离子表面活性剂十二烷基硫酸钠（SDS）、非离子表面活性剂吐温20（ Tween 20）及两者组成的混合胶束体系作为毛细管胶束电动色谱（MECC）的分离介 质，进行4种结构相似的酸性化合物的MECC分离研究，考察了胶束的类型、表面活 性剂的浓度、缓冲溶液的pH值及有机改性剂乙醇对分离的影响。结果表明各因素对 酸性药物的MECC分离有不同的影响规律。SDS胶束体系对溶质的保留值最大， Tween 20体系的保留值最小，二者的分离选择性正好相反，混合胶束体系的分离行 为则介于两者之间；在SDS和Tween 20体系中，表面活性剂浓度增加，溶质的保留 时间均随之递增，混合胶束体系中，总浓度一定，随Tween 20配比的增加，溶质的 保留时间先减少后增加；缓冲溶液的pH值增大，使溶质的分离效果均能变差；有机 改性剂乙醇的加入对容量因子的影响主要与溶质的疏水性有关，并对分离作用机理 进行了探讨。在SDS和Tween 20 MECC体系下，分别进行了实样测定，取得了满意的 结果。     

Fate of excited probes in micellar systems

This article presents studies on the photophysical and photochemical behavior of probes within micellar systems: organized emulsifier/polymer aggregates; the intra- and interpolymer association of amphiphilic polymers; monomer-swollen micelles (microdroplets); and the interfacial layer. Pyrene (Py) as a probe is particularly attractive because of its ability to measure the polarity of its microenvironment. Dipyme yields information on the microviscosity of micellar systems. Probes such as laurdan and prodan can be used to explore the surface characteristics of micelles or microdroplets. The dansyl group has a special photophysical property that gives information about the local polarity and mobility (viscosity) of the microenvironment. The organized association of amphiphilic polymer and emulsifier introduces a heterogeneity in the local concentration of the reactants. This heterogeneity also results from the attractive interaction between hydrophilic monomer and emulsifier in the case when the monomer carries a positive charge and the counterpart a negative one, and vice versa. Some emulsifiers can bind to the amphiphilic copolymers by simple partitioning between the aqueous phase and the polymer--non-cooperative association. The interaction between micelles (microdroplets) and charged polymers leads to the formation of mixed micelles. Binding emulsifiers to these polymers was detected at emulsifier concentrations much below the critical micellar concentration (CMC). Emulsifiers often interact cooperatively with polymers at the critical aggregation concentration (CAC) below the CMC, forming micelle-like aggregates within the polymer. The CAC can be taken as a measure of interaction between the emulsifier and polymer. A decrease in the monomer fluorescence intensity of probe-labeled polymer results from increased excimer formation, or higher aggregates within the unimolecular polymeric micelles. An increase in the monomer fluorescence intensity of probe-labeled polymer within the micellar system can be ascribed to shielding of the probe chromophores by emulsifier micelles. The quenching of probe emission by (un)charged hydrophilic monomer depends on partitioning of the monomer between the aqueous phase and the micelles. Penetration of reactants into the interfacial layer determines the quenching of the hydrophobic probe by hydrophilic quencher, or vice versa. Quenching depends on the thickness, density and charge of the interfacial layer. Compartmentalization prevents the carbonyl compound and unsaturated monomer from coming into sufficiently close contact to allow singlet or triplet-monomer interaction. All negatively charged carbonyl probe molecules are quenched with significantly lower rates than the parent neutral hydrophobic benzophenone molecules, which were located further inside the aggregates. This results from the different conformation and allocation of reactants within the micellar system. In the reverse micelles, quenching depends on the amount of water in the interfacial layer and the total area of the water/oil interface.     

Correlation of surfactant/polymer phase behavior with adsorption on target surfaces

In this contribution, the phase behavior of a surfactant/polymer mixed system is related to the adsorption of a complex derived from the mixture onto a target surface. The phase map for the system sodium dodecyl sulfate (SDS, a model anionic surfactant)/pDMDAAC (poly(dimethyl diallyl ammonium chloride), a cationic polymer) shows behavior very typical of surfactant/oppositely charged polyelectrolyte mixtures. The predominant feature is a broad, two-phase region in the phase map which lies asymmetrically around the 1:1 stoichiometry of surfactant charge groups to polymer charge units. The overall controlling principle driving the phase separation is charge compensation. Excess of polymer yields an isotropic solution, as does a great excess of surfactant (termed resolubilization). The phase separating in the SDS/pDMDAAC system is characterized by a positive zeta-potential when the polymer is in excess and a negative zeta-potential when the surfactant is in excess. The surface charge properties of the precipitated phases are essentially identical to those of target particles (ground borosilicate glass) dispersed at the same approximate position in the phase map, suggesting that the surfactant/polymer complex at the precipitation boundary is the same as that adsorbing onto the pigment particle. This conclusion is confirmed by depletion studies which allow the polymer adsorption density to be determined. For polymer-rich systems, essentially all of the surfactant adsorbs along with the polymer via a high-affinity isotherm with a plateau coverage of about 0.8 mg polymer/m (2). Surfactant-rich systems adsorb with a similar affinity, despite the mismatch of the complex charge matching that of the particle surface. Once adsorbed, these complexes are not readily removed by rinsing, though complexes adsorbed from SDS-rich systems will lose excess surfactant upon extreme dilution. Over a wide range of surfactant-rich compositions, from 1:1 stoichiometry out toward the resolubilization zone, a chemical analysis reveals that the surfactant/polymer precipitate species consists of a 1:1 charge complex with the addition of about 0.25 mol of surfactant/mol of complex. Resolubilization of these sparingly soluble species is achieved simply by dilution to below their solubility limit.     

Micellar and aqueous‐organic liquid chromatography using sub‐2 μm packings for fast separation of natural phenolic compounds

The objective of the present work was to investigate the chromatographic behavior of natural phenolic compounds in micellar and aqueous‐organic LC using a short column packed with 1.8 μm particles. Firstly, the effect of ACN and SDS on elution strength and selectivity was examined by isocratic submicellar (0–30% ACN/5% 1‐butanol/1–6 mM SDS) and micellar (0–30% ACN/5% 1‐butanol/40–60 mM SDS) systems. The varied concentrations of two modifiers in the mobile phases revealed different eluting power. Then, the application of organic modifier gradient was discussed in both submicellar and micellar LC using mobile phases of 4 mM SDS/5% 1‐butanol or 50 mM SDS/5% 1‐butanol containing ACN gradient from 0 to 30%, respectively. For micellar system, the separation was found to be better in gradient than isocratic elution. Additionally, the sensitivity of aqueous‐organic LC was examined. The mobile phase was a mixture of ACN and water employing gradient elution at a flow rate of 0.5 mL/min, with analysis time below 9 min. It was found that separation efficiency was significantly better compared with micellar LC. Besides, the aqueous‐organic LC has been applied to separation of various phenolic compounds in Yangwei granule or Radix Astragali samples.     

Protein pre-fractionation in detergent-polymer aqueous two-phase systems for facilitated proteomic studies of membrane proteins

Pre-fractionation of a complex mixture of proteins increases the resolution in analytical separations of proteins from cells, tissues or organisms. Here we demonstrate a novel method for pre-fractionation of membrane proteins by a detergent-based aqueous two-phase system. Membrane proteins are strongly under-represented in proteomic studies based on two-dimensional electrophoresis (2-DE). As a model system, we have isolated mitochondria from the yeast Saccharomyces cerevisiae. Mitochondrial proteins were fractionated in an aqueous two-phase system consisting of the polymer poly(ethylene glycol) and either of two commonly used non-ionic detergents, Triton X-114 or dodecyl maltoside (DDM). Soluble proteins partitioned mainly to the polymer phase while membrane proteins were enriched in the detergent phase, as identified from one-dimensional electrophoresis (1-DE) and/or 2-DE followed by mass spectrometric analysis. Pre-fractionation was further enhanced by addition of an anionic detergent, sodium dodecyl sulfate, or a chaotropic salt, NaClO4, and by raising the pH in the system. The two-phase system pre-fractionation was furthermore combined with an alternative two-dimensional high-resolution separation method, namely ion-exchange chromatography and 1-DE. By this approach a larger number of membrane proteins could be identified compared to separation with conventional 2-DE. Thus, pre-fractionation of complex protein mixtures using the aqueous two-phase systems developed here will help to disclose larger proportions of membrane proteins in different proteomes.     

pH Induced Partitioning and Interactions of Ciprofloxacin Hydrochloride with Anionic Surfactant Sodium Dodecyl Sulfate Using Ultraviolet and Fourier Transformed Infrared Spectroscopy Study

Ultraviolet (UV) and Fourier transformed infrared (FTIR) spectra of ciprofloxacin hydrochloride (Cpf) were studied under different pH conditions. The effect of aqueous, strong acidic, (pH 0.5–1.0) and a basic (pH 9.2) conditions on spectral behavior of Cpf was investigated in aqueous as well as in micellar environment of sodium dodecyl sulfate (SDS). Cpf shows partitioning from aqueous to micellar phase in a strong acidic as well as in a basic environment. Cpf shows no partitioning or binding to micelle in aqueous phase. Conductivity studies show that critical micelle concentration of SDS is increased with increasing concentration of Cpf. Different sites are responsible for binding under different pH conditions.     

Aqueous surfactant two-phase systems in a mixture of cationic gemini and anionic surfactants

The phase behavior as well as the microstructures of the cationic gemini surfactant and anionic conventional surfactant aqueous two-phase system (ASTP) have been studied. The ASTP formation can be attributed to the coexistence of different kinds of aggregates in the upper and lower phases. The effects of temperature, shearing, surfactant concentration and mixing molar ratio on the phase separation of the ASTP-forming systems are systematically investigated. The ASTP can be destroyed by applying shear and increasing temperature. In this process, the lamellar structures (flat bilayers) in the ASTP are transformed into vesicles. Variation of surfactant structure also affects the phase behavior and the aggregates transformation. Appropriate molecular packing is crucial for the formation of ASTP.     

正负离子表面活性剂与高聚物混合双水相体系的相行为及蛋白质的分配

报道了由正负离子表面活性剂与高聚物混合溶液形成的一种可用于蛋白质的分离及分析的新型双水相萃取体系.研究了正负离子表面活性剂(溴化十二烷基三乙铵/十二烷基硫酸钠)分别与葡聚糖和聚乙二醇混合双水相体系的形成规律、相行为及牛血清蛋白和溶菌酶在双水相体系中的分配.通过在高聚物分子中接上亲和配基,研究蛋白质在双水相体系中的亲和分配.结果表明,在该体系中,表面活性剂与高聚物分别富集于不同相中.升高温度及加入无机盐均可促进双水相体系的形成,不同蛋白质可分配于不同的相中.亲和配基的引入极大地增强了蛋白质分配的选择性.     

Effect of added poly(oxyethylene)dodecyl ether on the phase and rheological behavior of wormlike micelles in aqueous SDS solutions

Upon the addition of a short EO chain nonionic surfactant, poly(oxyethylene) dodecyl ether (C12EOn), to dilute micellar solution of sodium dodecyl sulfate (SDS) above a particular concentration, a sharp increase in viscosity occurs and a highly viscoelastic micellar solution is formed. The oscillatory-shear rheological behavior of the viscoselastic solutions can be described by the Maxwell model at low shear frequency and combined Maxwell-Rouse model at high shear frequency. This property is typical of wormlike micelles entangled to form a transient network. It is found that when C12EO4 in the mixed system is replaced by C12EO3 the micellar growth occurs more effectively. However, with the further decrease in EO chain length, phase separation occurs before a viscoelastic solution is formed. As a result, the maximum zero-shear viscosity is observed at an appropriate mixing fraction of surfactant in the SDS-C12EO3 system. We also investigated the micellar growth in the mixed surfactant systems by means of small-angle X-ray scattering (SAXS). It was found from the SAXS data that the one-dimensional growth of micelles was obtained in all the SDS-C12EOn (n=0-4) aqueous solutions. In a short EO chain C12EOn system, the micelles grow faster at a low mixing fraction of nonionic surfactant.