聚苯乙烯-b-聚丙烯酸/聚苯乙烯在水中的自组装及胶束尺寸的研究

利用动态光散射、透射电镜研究了嵌段共聚物聚苯乙烯 b 聚丙烯酸(PS b PAA)与均聚物聚苯乙烯(PS)在选择性溶剂水中的自组装行为.由于均聚物PS与PS嵌段具有相同的结构单元,均聚物PS参与胶束的形成,和嵌段共聚物的PS链段一同组成胶束的核;在适当的均聚物分子量和含量条件下,PS b PAA PS可以自组装形成单分散的纳米胶束;通过改变体系中均聚物PS的分子量和含量可在较大范围内调变胶束的尺寸.     

Voltammetric analysis of hydroquinone, ascorbic acid, nitrobenzene and benzyl chloride in aqueous, non-aqueous, micellar and microemulsion media

Voltammetric behaviour of hydroquinone, ascorbic acid, nitrobenzene and benzyl chloride in aqueous, micellar, microemulsion and aprotic media on glassy carbon electrode under identical experimental conditions was compared. A general trend of decreasing peak currents in the order was noticed. The only exception was hydroquinone, which exhibited a slightly lower current in micellar medium. The peak potentials for each of these compounds varied in the order with due consideration for the two oxidation and reduction processes (negative E _P values for reduction). In micellar systems, which contain a predominantly aqueous phase where the cationic surfactant exhibits a catalytic effect, lower peak potentials and higher current are obtained. The peak potential and peak current is lower in microemulsion when compared to aprotic medium. The causes for such systematic variations and their analytical implications are discussed.     

Amphiphilic random polycarbonate self-assemble into GSH/pH dual responsive micelle-like aggregates in water

Responsive polymers have been playing an increasingly important role in a wide variety of applications,such as biomedical materials and biosensors.Herein,we reported a dual-responsive polycarbonate(poly(MN-co-MSS)) based on the macrocyclic Sulfur/Nitrogen-substituted carbonate monomer(MSS/MN) via an enzyme-catalyzed ring-opening copolymerization and Lipase CA Novozym-435 as catalyst,with the disulfide and tertiary amine groups situated on the backbone.The structure of the random copolymers was confirmed by NMR and FTIR.In addition,size exclusion chromatography(SEC) results indicated that the copolymer had a symmetric peak and a relatively narrow polydispersity.Also,the random copolymers can self-assemble into micelle-like aggregates in water due to the hydrophilicity endowed by the amino groups,and the aggregates exhibited rich pH and GSH responsive behavior,which was verified by zeta masters instrument and dynamic light scattering(DLS).Moreover,transmission electron microscopy(TEM) demonstrated the morphology of the micellar aggregates and the variation subjected to the lower pH and GSH,and the responsive mechanism was elaborated.Therefore,these results highlighted a facile synthesis of the environment-responsive polymers and provided a novel GSH/pH responsive material platform for further application.     

A small angle neutron scattering study on the mixtures of pluronic L121 and anionic surfactant AOT

Small angle neutron scattering (SANS) experiments have been carried out on the micellar solutions containing mixtures of a hydrophobic triblock copolymer (L121, EO₅PO₆₈EO₅) and a hydrophobic anionic surfactant (AOT, sodium bis(2-ethylhexyl)sulphosuccinate) in water with varying ratio (R) of AOT to L121 for R = 0.15, 0.2, 0.3, 0.5 and 0.6. It is known that either L121 or AOT alone forms vesicles in water, but in the mixture with appropriate ratio of the two components a thermodynamically stable, isotropic solution of apparently small micelle-like aggregates is formed. We find that these micelles are prolate ellipsoidal.      

Beiträge zur Chemie der Pyrrolpigmente, 67. Mitt.

Bilatrienes-abc and 2,3-dihydrobilatrienes-abc are effectively solubilised by cationic, anionic and neutral surfactants, like cetyltrimethylammonium bromide, sodium dodecylsulfate and Triton-X-100. The absorption spectra of the solubilised pigments are comparable to those of solutions in common organic solvents. Accordingly, the configurations and conformations of the predominant populations remain unchanged in the micellar systems, compared to solutions. The apparent basicities and acidities of the pigments in micelles are different from those in aqueous solutions, however. This phenomenon may have implications for physiological systems. Two lipophilic pigments bearing long alkyl side chains are newly synthesised.

Herrn Prof. Dr.K. Komarek zum 60. Geburtstag gewidmet.     

Structural dynamics,phase behavior,and applications of polyelectrolyte complex micelles

Self-assembly between oppositely charged polyelectrolytes conjugated to neutral polymeric blocks form polyelectrolyte complex (PEC) micelles. These nanostructures have gained significant interest in the field of nucleic acid and protein delivery, along with emerging applications in biosensing and catalysis. These carriers are highly modular systems, with the ability to engineer stimuli-responsive and targeting properties, making them smart platforms for biomedical applications. In this review, we discuss the current understanding of mechanisms involved in the assembly and disassembly of these nanoparticles, and the structural and functional changes as a response to solution conditions. We also discuss the latest and most impactful applications of PEC micellar systems in the biomedical field, with far-reaching influence on the treatment of various human diseases.     

组装-聚合法制备聚苯乙烯-聚丙烯酸胶束和凝胶

通过苯乙烯和丙烯酸单体的预组装再聚合的制备方法,在不改变共聚物浓度的前提下制备了共聚物胶束溶液和凝胶,探讨了引发剂(偶氮二异丁腈)浓度对生成的共聚物的聚集体结构以及分子结构的影响.利用核磁共振氢谱、扫描电子显微镜和透射电子显微镜等表征了共聚物的分子结构和聚集行为,此外,借助耗散粒子动力学方法模拟了该体系,辅助实验阐明了不同引发剂浓度下生成的共聚物聚集体结构及相对应的共聚物分子结构,在此基础上,利用动态机械热分析和流变学的表征技术,研究了共聚物胶束溶液和凝胶的流变特性.结果表明,在单体浓度不变的情况下,高引发剂浓度时该体系趋于形成平均嵌段长度较长的两嵌段共聚物,生成稳定的胶束溶液,而低引发剂浓度时趋于形成交替共聚物,得到物理凝胶,耗散粒子动力学模拟得到了与实验一致的结果.流变学表征发现胶束体系和凝胶体系均呈现剪切变稀行为,并确定了凝胶体系的凝胶点及恢复性.     

两亲聚合物胶束自组装包药研究进展

两亲聚合物胶束具有突出的理化性能和独特功能,能够在溶液中自组形成具有核壳结构的聚合物胶束,同时实现药物的负载。自组装包药技术能够缓解我国药物辅料缺乏的现状,符合目前药物辅料发展的新趋势。通过自组装形成的聚合物胶束在药物控释、药物靶向载体、药物制剂开发、新型药物辅料等方面具有广阔的应用前景。本文综述了两亲聚合物胶束自组装包载药物的原理以及方法,重点介绍了三类两亲聚合物在自组装包药方面的最新研究成果和发展趋势。本文还对载药胶束在药物释放方面的应用进行了概述。     

meso-四(4-磺基苯基)卟啉(TPPS)在水及胶束体系中的二聚行为研究

研究了meso-四（4-磺基苯基）卟啉（TPPS）在胶束（TritonX－100）、KCl水溶液中的电子吸收光谱变化,计算了TPPS的二聚常数KD,用分光光度法研究了TPPS在KCI水溶液中的二聚反应动力学,提出了与实验结果相吻合的二聚机理．根据温度对二聚平衡的影响,计算了二聚平衡的乙和     

基于温敏性双亲嵌段共聚物的纳米胶束作为药物载体的研究

温度敏感性双亲嵌段共聚物由于其潜在的应用价值而引起广泛的关注。在药物控制释放领域,基于温敏性嵌段共聚物的纳米胶束作为药物载体显示了诸多特异的性能。在嵌段共聚物中引入具有温度敏感性的链段,使聚合物胶束具备天然被动靶向功能的同时,赋予了其主动靶向给药功能。本文从温度敏感性双亲嵌段共聚物的分子设计、合成、自组装性质和胶束的载药释药行为等方面进行了相关总结。重点介绍了含聚N-异丙基丙烯酰胺链段双亲嵌段共聚物的相关研究进展。