两亲性嵌段共聚物的自组装及载药胶束的研究

采用可逆-加成-断裂链转移自由基聚合(RAFT)技术合成了两亲性嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸聚乙二醇单甲醚-b-聚苯乙烯(PSt-b-POEOMA-b-PSt),通过FT-IR、1 HNMR、GPC确定共聚物的结构。将三个具有不同嵌段比的共聚物在水溶液中自组装,通过透射电子显微镜(TEM)观察得到的胶束的形貌,发现随着亲水性嵌段的比例减小,胶束的直径略微减小。通过透析方法,以共聚物作为载体,负载维生素E,TEM观察载药胶束的形貌,仍然为核-壳状的球形胶束。差示扫描量热仪(DSC)测试共聚物载药胶束前后的热性能,发现药物分子在载入内核的过程中,聚苯乙烯的玻璃化转变温度(Tg)有所降低。通过紫外(UV)分析计算得出共聚物的药物负载量(DLC)为70%～80%。     

两亲性壳聚糖衍生物的合成及其自聚集现象

以壳聚糖为主链, 聚乙二醇单甲醚为亲水性链段, 癸二酸为疏水链段, 合成了一系列两亲性壳聚糖衍生物. 通过FTIR, 1H NMR和X射线粉末衍射等手段对壳聚糖衍生物进行了结构表征, 由元素分析方法计算出衍生物的取代度. 采用直接溶解法制备了壳聚糖衍生物的空白胶束, 通过透射电子显微镜(TEM)观察了胶束的形态. 由动态光散射(DLS)测定了胶束的粒径及分布, 并以芘为分子探针, 通过荧光光谱法测定了壳聚糖衍生物的临界聚集浓度(CAC). 研究结果表明, 壳聚糖主链上疏水链段的取代度越大, 其衍生物的临界聚集浓度越低, 相同浓度下的胶束的粒径也越小.     

The Effect of Sodium Dodecylbenzenesulfonate (SDBS) Micelles on a BelousovZhabotinsky Oscillating System Catalyzed with a Tetraazamacrocyclic Copper(II) Complex

This article deals with the influence of micelles of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on the Belousov? Zhabotinsky (B? Z) oscillating reaction catalyzed by a tetraazamacrocyclic copper(II) complex [CuL](ClO₄)₂, an enzyme‐like catalyst (L=5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradeca‐4,11‐diene). Unlike the classical B? Z oscillator in which malonic acid is usually used as a substrate, malic acid (an intermediate in the Krebs cycle) is involved in this oscillating system. Experiments reveal that formation of the SDBS micelles markedly affects the behavior of the oscillating reaction. It is found that there is a linear relationship between the change in the oscillation amplitude (ΔA) and the concentration of SDBS, whereas the change in the oscillation period (ΔT) is linearly proportional to the SDBS concentration. The most likely mechanism that involves the formation of the SDBS micelles and the effects of the micelles on the oscillating chemical system can be rationalized by assuming that the SDBS micelles are so negatively charged that they attract more [CuL]³⁺ than [CuL]²⁺. This hypothesis was confirmed by UV/VIS spectrophotometric measurements of a constant concentration of [CuL](ClO₄)₂ in different concentrations of SDBS; as the SDBS concentration increased, the absorbance of [CuL](ClO₄)₂ increased, while the maximum absorption wavelength for [CuL](ClO₄)₂ remained at 502 nm.     

Rheological Behavior of Viscoelastic Wormlike Micelles in CTAB/SSS/H2O Systems

The effect of the addition of sodium 4-styrenesulfonate (SSS) and KNO3 as well as temperature and shear rate on the structural transition of aqueous micellar solutions of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) was studied by viscosity. The effect of hydrocarbons on viscoelastic CTAB solutions was also examined. Possible mechanism for formation of CTAB wormlike micelles in the presence of sodium 4-styrenesulfonate (SSS) and KNO3 was discussed. The rapid increase in the apparent viscosity of CTAB solutions on the addition of SSS and KNO3 was due to the transition in micellar shape from spheres to wormlike ones. The rheological properties of CTAB solutions fit Maxwell model at low shear frequency. AFM image indicated a structure of transient network of CTAB/SSS/KNO3/H2O solution.     

阳离子Gemini表面活性剂3,5-双(亚甲基十八烷基二甲基溴化铵)-1,2,4-三氮唑胶束对酯碱性水解的影响

在25℃条件下,研究了乙酸乙酯和乙酸戊酯在阳离子Gemini表面活性剂3,5—双(亚甲基十八烷基二甲基溴化铵)—1,2,4—三氮唑(简称18—triazole—18)胶束中的碱性水解反应。实验结果表明．在一定的表面活性剂浓度范围内,乙酸乙酯和乙酸戊酯在Gemini表面活性剂18—triazole—18胶束溶液中的碱性水解反应速率随表面活性剂浓度的增加呈上升趋势,达到一最大值后,随着浓度的增加呈下降趋势。实验结果还表明,18—triazole—18对乙酸乙酯碱性水解的影响较对乙酸戊酯碱性水解的影响大。随着底物疏水性的增加,乙酸乙酯和乙酸戊酯的碱性水解速率在18—triazole—18胶束中表观反应速率常数最大值分别为无表面活性剂时的5．5倍和1．1倍。     

Aggregation phenomena of linear and miktoarm star copolymers of styrene and dimethylsiloxane: Influence of the architecture

The micellar behavior of PS-b-PDMS, PS-b-PDMS-b-PS linear block and (PS)₂(PDMS) miktoarm star copolymers of polystyrene (PS) and polydimethylsiloxane (PDMS) is investigated in DMF, a selective solvent for PS. The linear PS-b-PDMS and star (PS)₂(PDMS) copolymers exhibit different macromolecular architectures but similar compositions and total molecular weight, while the linear PS-b-PDMS-b-PS copolymer has the same composition as the diblock and miktoarm star but double their molecular weight. Static, dynamic light scattering and viscometry were used for the structural characterization of the micelles. Aggregation numbers were found to increase in the order PS-b-PDMS-b-PS < (PS)₂(PDMS) < PS-b-PDMS. The corona thickness was dependent on the molecular weight of the soluble PS chains. In the case of (PS)₂(PDMS), although the core area per PS chain, A_C, was significantly lower than that of the linear copolymers, the coronal chains were not significantly stretched. This can be attributed to the stiff nature of the PS chains, which maintains the elongated form of the chains.     

Adsorption layer properties and foam film drainage of aqueous solutions of tetraethyleneglycol monododecyl ether

The aim of the present study is to clarify how the surfactant adsorption layer properties are related to the course of the drainage parameters of microscopic foam films in the special case of aqueous solutions of the non-ionic amphiphile tetraethyleneglycol monododecyl ether (C₁₂E₄), containing premicellar nanostructures. The scope of the research covers adsorption dynamics, construction of equilibrium adsorption isotherms, studies on surface rheology of the interfacial layers and microscopic foam film drainage kinetics. It is established that in the premicellar concentration domain considerable irregularities of the adsorption layer properties are observed: two plateau regions are registered in the experimental surface tension isotherm along with unusual changes of the surface rheological characteristics. The systematic investigation of the drainage of microscopic foam films obtained from these solutions show that the dependencies of basic kinetic parameters of the films on the amphiphile concentration run in synchrony with the changes in the adsorption layer properties. This fact is related to the presence of smaller surfactant aggregates (premicelles). They are presumed to be organized as Platonic bodies. The premicelles play also a significant role in the kinetic stability of the films. The importance of this research is in providing better insight into the initial stages of self-assembling phenomena and into the factors determining the adsorption layer properties and the drainage behaviour of thin liquid films.     

聚电解质微球多级自组装制备双重药物载体

将表面带正电荷的壳聚糖(CS)微球和表面带负电荷的聚(L-谷氨酸)-b-聚氧化丙烯-b-聚(L-谷氨酸)(GPG)胶束共混,制备了CS/GPG聚集体水溶液体系.通过改变CS/GPG的共混比例,研究了CS微球和GPG胶柬形成稳定CS/GPG聚集体水溶液体系的配比范围,并对其粒径分布和表面电位进行了表征.在此基础上,将CS...     

聚(辛二酸-四甘醇酯)的合成及其微相分离结构的研究

通过熔融缩聚合成了一种新型的两亲性聚酯——聚(辛二酸-四甘醇酯)(PTEGSub),利用GPC,NMR,FTIR,TG,DSC等手段对聚合物的结构进行了表征.研究发现,在25℃时,PTEGSub在水中可以形成胶束,粒径主要集中在20～120nm之间,其临界胶束浓度(CMC)随分子量的升高而降低.通过TEM观察了在选择性溶剂中的胶束形态.利用AFM研究了PTEGSub的微相分离,发现聚合物膜中存在有球状的相分离结构.     

Triton X-100在乙二醇中的胶体性质

表面活性剂在非水溶剂中聚集态的研究所见的报导与水体系相比要少得多．然而近年来对非水体系的研究日益增多．这是因为表面活性剂在非水溶剂中的应用日趋增加，但与水体系相反，对非水体系的性质了解甚少．对表面活性剂非水体系的研究还有助于对其聚集体的共溶剂效应有更深的认识．TritonX－100（以下简写为TX－100）是典型的非离子表面活性剂，在工业上有着广泛的应用．乙二醇在多醇中与水的化学结构最相近问，然而它却是水结构的破坏剂，加入少量的乙二醇会使水的冰点急剧下降．乙二醇又是蛋白质的变性溶剂．表面活性剂在乙二醇中的胶…