聚苯乙烯-b-聚氧乙烯-b-聚苯乙烯三嵌段共聚物的自组装

小分子表面活性剂、磷脂、接枝及嵌段共聚物等两亲分子在选择性介质中能够自组装形成特定的分子聚集体 [1,2 ] .嵌段共聚物自组装的某些行为具有生物膜模拟性 ,如最近发现的嵌段共聚物自组装囊泡 [3～ 5] .诸多因素影响着嵌段共聚物在稀溶液中的自组装行为 [6] .对于 ABA型三嵌     

嵌段共聚物自组装的研究进展

自组装是分子间通过非共价键相互作用自发组合形成的一类结构明确、稳定,同时具有某种特定功能或性能的分子聚集体或超分子结构的现象.嵌段共聚物不仅可以在本体中自组装,还能在溶液中自组装.本文综述了嵌段共聚物在溶液中自组装的规律及其主要影响因素,包括嵌段共聚物链段长度、选择性溶剂的性质、嵌段共聚物的浓度、溶液的pH值等;并介绍...     

ABC三嵌段共聚物的聚合诱导自组装研究

聚合诱导自组装(PISA)是一种在高浓度溶液中可连续大量制备纳米材料的新技术,结合计算模拟方法,研究其动力学过程可强化对PISA的认识和调控.通过耗散粒子动力学(DPD)模拟,研究了ABC三嵌段共聚物的聚合诱导自组装过程.先利用亲溶剂A链段引发B单体聚合,随着疏溶剂B链段的增长,AB二嵌段共聚物可组装并发生聚集体结构的连续转变,由球形胶束→蠕虫状胶束→层状结构→囊泡.再将C单体逐步聚合到AB共聚物上,调控C链段的亲疏溶剂性,可聚合诱导组装或解组装形成不同的ABC三嵌段共聚物聚集体.     

双亲半柔性两嵌段共聚物在溶液中自组装形态的模拟退火研究

针对一系列疏溶剂嵌段与溶剂间的相互作用,用模拟退火方法研究了双亲半柔性两嵌段共聚物在溶液中的自组装形态.模拟结果显示共聚物在溶液中均形成核-壳聚集体,其中疏溶剂嵌段形成聚集体的核,亲溶剂嵌段形成聚集体的壳.当上述相互作用较小时,核呈球形,而壳如同长在核上的刺.随着上述相互作用的增大,核逐渐增大.在较大的相互作用时,核呈柱形;而随着相互作用的加大,长在核上的刺逐渐伏贴于核表面.在更大的相互作用时,核又呈球状,壳伏贴于核表面.     

基于P4VP-b-PBzMA嵌段聚合物在乙醇中的聚合诱导自组装

聚合诱导自组装是一种基于活性聚合的新型自组装策略,其特点是可以在较高固含量体系中一步制备不同形貌的聚集体结构.利用可逆加成-断裂链转移聚合(RAFT)活性聚合,在乙醇溶液中合成新型P4VP-b-PBz MA嵌段共聚物,发现聚合诱导自组装过程中聚集体结构发生球→蠕虫→囊泡的连续转变.亲溶剂链段P4VP的变化可有效调控聚集体的结构和尺寸.此外,采用无规共聚方法,研究了P4VP-b-(PHPMA-co-PBz MA)三嵌段共聚物在聚合诱导自组装过程中组装体结构的转变过程.     

嵌段共聚物调控纳米粒子自组装的研究进展

嵌段共聚物和纳米粒子复合纳米材料具有优异的性能,在生物医药、光电材料、催化材料等领域具有很大的应用价值,已成为备受关注的研究热点.利用嵌段共聚物自组装能够形成特定形态的纳米结构聚集体,将纳米粒子选择性的分布和定位于嵌段共聚物聚集体中,可以改善纳米粒子的性能及其应用.本文综述了近年来实验上利用自组装制备嵌段共聚物-纳米粒子复合纳米材料的方法,并总结分析了影响纳米粒子在嵌段共聚物聚集体中的分布和定位的各种因素,包括纳米粒子的大小、形状及其表面化学.最后总结了嵌段共聚物-纳米粒子的自组装在理论模拟方面的研究.     

稀溶液中Rod-Coil-Rod三嵌段共聚物组装结构的耗散粒子动力学模拟（英文）

采用耗散粒子动力学方法模拟研究了rod-coil-rod三嵌段共聚物在稀溶液中的聚集行为.分别考察了rod-coil嵌段的相互作用、溶剂性质、共聚物浓度以及coil嵌段长度对聚集体形貌的影响.模拟结果发现,随着rod-coil相互排斥作用的增加,共聚物由球形转变成洋葱状、笼形和柱状结构.随着coil嵌段疏水性的增加,笼形转变成洋葱状和补丁状结构.给出了聚集体形貌随共聚物浓度和coil长度变化的相图.当浓度较小和coil嵌段较长时,共聚物形成笼状聚集体,反之,则有利于洋葱状结构的形成.     

稀溶液中Rod-Coil-Rod三嵌段共聚物组装结构的耗散粒子动力学模拟

采用耗散粒子动力学方法模拟研究了rod-coil-rod 三嵌段共聚物在稀溶液中的聚集行为. 分别考察了rod-coil 嵌段的相互作用、溶剂性质、共聚物浓度以及coil 嵌段长度对聚集体形貌的影响. 模拟结果发现,随着rod-coil 相互排斥作用的增加,共聚物由球形转变成洋葱状、笼形和柱状结构. 随着coil 嵌段疏水性的增加,笼形转变成洋葱状和补丁状结构. 给出了聚集体形貌随共聚物浓度和coil 长度变化的相图. 当浓度较小和coil 嵌段较长时,共聚物形成笼状聚集体,反之,则有利于洋葱状结构的形成.     

双刚性共轭嵌段共聚物体系的自组装

棒杆-棒杆(rod-rod)共轭嵌段共聚物体系是近几年发展起来的一类新型共轭聚合物材料,由于其特有的电学活性以及通过自组装实现纳米尺度结构可控等特性正逐渐成为人们研究的热点.构筑单元的刚性棒状结构使得rod-rod共轭嵌段共聚物体系倾向于自组装形成囊泡或层状结构等低曲率聚集体.本文总结了近年来关于rod-rod共轭嵌段共聚物体系自组装行为的研究,分别介绍了溶液中以及薄膜状态下双刚性共轭嵌段共聚物体系的自组装行为,在此基础上进一步讨论了rod-rod共轭嵌段共聚物薄膜结构与性能的关系.     

刺激响应性刚柔嵌段共聚物的自组装

刚柔嵌段共聚物是指刚性链段和柔性链段以共价键相连形成的共聚物。不仅由于刚性链段有序排列的特点使得其自组装行为更为丰富多样,而且刚性分子将优异的功能特性赋予到超分子组装体中,有望实现超分子材料的功能应用。这类嵌段共聚物在溶液中自组装形成的聚集体会对外界的刺激(例如pH、光、温度、化学添加剂等)敏感,产生聚集体形态的变化。本文选取了部分典型的具有刺激响应性的刚柔嵌段共聚物,介绍了其智能自组装行为,并对其良好的发展前景做了展望。     

Block polyelectrolytes in aqueous environments

Analogous to the self-assembly of low-molecular-weight amphiphiles in aqueous solutions, the formation of spherical micelle-like aggregates has been observed in systems of amphiphilic block copolymers in water. The aggregates, often called micelles due to structural similarities with surfactant associates, are found to exist above the critical micelle concentration (cmc). The micellization of amphiphilic block copolymers has been investigated using a wide range of techniques, such as size-exclusion chromatography (SEC), static and dynamic light scattering (SLS and DLS), small-angle x-ray scattering (SAXS), small-angle neutron scattering (SANS), transmission electron microscopy (TEM), viscometry, and steady-state fluorescence spectroscopy. The present lecture is a review of recent work in our laboratory concerning the micellization of ionic block copolymers. These high-molecular-weight amphiphiles may contain one or more of a variety of ionic blocks, such as poly(4-vinylpyridinium alkyl halides), poly(metal acrylates), poly(metal methacrylates) and sulfonated polystyrene. In water, such polymers are referred to as block polyelectrolytes, as they combine the colloidal behavior of block copolymers with the long-range electrostatic interactions of polyelectrolytes. Early work in this field has been reviewed by Selb and Gallot.¹     

Self-assembly of Amphiphilic Alternating Copolymers

Polymer self-assembly has been a hot research topic for several decades. Different types of polymers with various architectures, like block copolymers, brush polymers, hyperbranched polymers and dendrimers, etc., are currently being investigated. Alternating copolymers (ACPs) are regular copolymers with an alternating monomeric unit structure in the polymer backbones. However, despite the great progress in the synthesis of ACPs, their self-assembly is still in an infant stage. Very recently, our group reported a new type of amphiphilic ACPs through click copolymerization and obtained spheres, vesicles, nanotubes, and even hierarchical sea urchin-like aggregates through the self-assembly process. In addition, we have found some intriguing features in the self-assembly of amphiphilic ACPs when compared with other copolymers, including their facile syntheses, readily functionalization, novel self-assembly structures, new folding-chain mechanisms, and uniform but ultrathin feature length. In this Concept article, we present the self-assembly of amphiphilic ACPs together with their unique features by reviewing our latest results and related studies. Moreover, the future perspective on the self-assembly of amphiphilic ACPs is also proposed. Our aim is to capture the attention and interest of chemists in this new area of polymerization.     

经两亲嵌段共聚物自组装制备纳米胶束

本文介绍两亲嵌段共聚物的合成,综述了经两亲嵌段共聚物自组装制备纳米胶束的研究进展,并对该领域的发展趋势进行了展望。     

聚醚树枝体－聚丙烯酸嵌段共聚物的水溶液自组装行为

应用UV－Vis、荧光、光物理探针、动态激光光散射和透射电镜(TEM)方法研究了聚醚树枝体与聚丙烯酸两亲嵌段共聚物(Dendr,PE-PAA)在水溶液中分子自组装行为。实验结果表明通过聚醚树枝体嵌段的疏水作用,易缔合形成聚集体,具有很低(10^-6～10^-7mol·L^-1)的临界缔合浓度(cac)。透过电镜观察到聚集体具有双层膜结构的球状、单室囊泡。临界缔合浓度(cac)以及聚集体的大小对枝状体的代数(Gi)及线性体的聚合度(n)具有明显的依赖关系。     

Poly(2-[dimethylamino]ethyl methacrylate)-b-poly(hydroxypropyl methacrylate)/DNA polyplexes in aqueous solutions

This study involves the investigation of the complexation ability of poly(2-[dimethylamino]ethyl methacrylate)-b-poly(hydroxypropyl methacrylate) (PDMAEMA-b-PHPMA) amphiphilic pH and thermoresponsive block copolymers, and their quaternized counterparts QPDMAEMA-b-PHPMA, toward short DNA in aqueous solutions. The PDMAEMA-b-PHPMA amphiphilic block copolymers present various self-assembly characteristics when inserted into aqueous media, depending on the composition, the solubilization protocol, the acidity and the temperature of the aqueous media. Copolymer aggregates-DNA interactions and nanostructure formation after complexation are investigated by dynamic light scattering and intensity measurements in aqueous solutions in a fixed temperature range, utilizing two different solubilization protocols for the copolymers. Ethidium bromide assays by fluorescence spectroscopy and ζ-potential measurements were also utilized to investigate the structure and properties of the DNA/copolymer polyplexes. The interpretation of such physicochemical characterization provides extra comprehension of the novel (Q)PDMAEMA-b-PHPMA copolymers self-assembly characteristics and assesses their ability for DNA complexation, stabilization, and delivery.     

双亲嵌段共聚物自组装特性的计算机模拟

双亲嵌段共聚物在不同体系下会自组装成各种形貌的超分子聚集体,是目前人们研究的热点,并在工业领域得到了广泛应用。计算机模拟是研究其自组装特性机理及聚集体结构、动态性质的有效工具。本文对近年来嵌段共聚物自组装特性的热力学模型和动力学模拟的研究进展进行了综述,分析了其中存在的问题并进行了展望。     

Poly(dimethylaminoethyl methacrylate)‐b‐poly(hydroxypropyl methacrylate) copolymers: Synthesis and pH/thermo‐responsive behavior in aqueous solutions

The synthesis and self‐assembly properties in aqueous solutions of novel amphiphilic block copolymers composed of one hydrophilic, pH and temperature responsive poly(dimethyl amino ethyl methacrylate) (PDMAEMA) block and one weakly hydrophobic, water insoluble, potentially thermoresponsive poly(hydroxy propyl methacrylate) (PHPMA) block, are reported. The block copolymers were prepared by RAFT polymerization and were molecularly characterized by size exclusion chromatography, NMR, and FTIR spectroscopies. The PDMAEMA‐b‐PHPMA amphiphilic block copolymers self‐assemble in different nanostructured aggregates when inserted in aqueous media. The effects of different solubilization protocols, as well as the effects of solution temperature and pH on the structure of the aggregates, are studied by light scattering and fluorescence spectroscopy measurements. Experimental results indicate that there is a number of solution preparation and physicochemical parameters that allow the control and manipulation of the structure and thermoresponsive properties of PDMAEMA‐b‐PHPMA aggregates in aqueous media. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1962–1977     

Poly(2-(dimethylamino)ethyl methacrylate)-b-poly(hydroxypropyl methacrylate) copolymers/bovine serum albumin complexes in aqueous solutions

Complexation ability of poly(2-(dimethylamino)ethyl methacrylate)-b-poly(hydroxy propyl methacrylate) (PDMAEMA-b-PHPMA) amphiphilic doubly thermo-responsive block copolymers, and their quaternized counterparts QPDMAEMA-b-PHPMA, toward bovine serum albumin (BSA) is studied in aqueous solutions. The PDMAEMA-b-PHPMA amphiphilic block copolymers self-assemble in nanostructured aggregates with PDMAEMA coronas having different inner structure and micro-polarity depending on the solubilization protocol utilized when inserted in aqueous media. By incorporating different BSA concentrations, we investigate the copolymer–protein interactions by light scattering measurements in aqueous solutions in a broad temperature range, utilizing different solubilization protocols for the copolymers. Fluorescence spectroscopy and ζ-potential measurements were also utilized to investigate the structure and properties of the copolymer/protein complexes formed in each case. Such knowledge may lead to a better understanding of the inner structure and micro polarity of the nanostructured aggregates formed by the novel (Q)PDMAEMA-b-PHPMA copolymers, along with their potential abilities in nanocarrier formation, protein complexation, stabilization, and delivery.     

Morphological control and molecular recognition by bis-urea hydrogen bonding in micelles of amphiphilic tri-block copolymers

Hydrogen bonding between urea groups of amphiphilic tri-block copolymers considerably affects their self-assembly in water, which results in a strong modification of morphology and viscosity of aqueous solutions; the hydrogen bonding motif in these amphiphilic copolymers allows molecular recognition of small molecules with complementary hydrogen bonding units.     

pH-responsive amphiphilic hybrid random-type copolymers of poly(acrylic acid) and poly(acrylate-POSS): synthesis by ATRP and self-assembly in aqueous solution

The synthesis and subsequent self-assembly of novel, random-type amphiphilic pH-responsive hybrid copolymers, having acrylic acid as pH-responsive hydrophilic and acrylate-polyhedral oligomeric silsesquioxane (POSS) as hydrophobic constituents are reported. The synthesis was carried out in two steps: first, t-butylacrylate and acrylate-POSS are copolymerized by ATRP, followed by the acid hydrolysis of t-butyl acrylate constituents of the synthesized poly(t-butylacrylate)-co-poly(acrylate-POSS) copolymers to achieve poly(acrylic acid)-co-poly(acrylate-POSS). It was found that POSS is a powerful hydrophobic unit. With very low POSS concentration in the copolymers, i.e., one POSS unit per 40 to 110 acrylic acid repeat units, the obtained amphiphilic hybrid copolymers could self-assemble in aqueous solution to form nanoaggregates, as revealed by the laser light scattering and fluorescence studies on the aqueous solutions of the obtained copolymers. The formation of hydrophobic core in the self-assembled aggregates is verified by the solubilization of pyrene (used as probe in fluorescence measurements) in aqueous solution of the copolymers. In addition to pH-dependent self-assembly behavior, it is also demonstrated that the particle size and aggregation number of the aggregates can be tuned simply by varying the composition of the copolymer, i.e., by changing the molar ratio of poly(acrylic acid) to poly(acrylate-POSS) in the copolymer. Finally, preliminary results on the influence of salt (NaCl) on the self-assembly of poly(acrylic acid)-co-poly(acrylate-POSS) in aqueous solution are also presented.