Mesoscale Block Copolymers

Materials composed of well‐defined mesoscale building blocks are ubiquitous in nature, with noted ability to assemble into hierarchical structures possessing exceptional physical and mechanical properties. Fabrication of similar synthetic mesoscale structures will offer opportunities for precise conformational tuning toward advantageous bulk properties, such as increased toughness or elastic modulus. This requires new materials designs to be discovered to impart such structural control. Here, the preparation of mesoscale polymers is achieved by solution fabrication of functional polymers containing photoinduced chemical triggers. Subsequent photopatterning affords mesoscale block copolymers composed of distinct segments of alternating chemical composition. When dispersed in appropriate solvents, selected segments form helices to generate architectures resembling block copolymers, but on an optically observable size scale. This approach provides a platform for producing mesoscale geometries with structural control and potential for driving materials assembly comparable to examples found in nature.     

Metallo‐Supramolecular Block Copolymers

Supramolecular copolymers have become of increasing interest in recent years for the search of new materials with tunable properties. In particular, metallo‐supramolecular block copolymers—copolymers in which the blocks are linked together by a metal–ligand complex—have seen important progresses, allowing better control over the synthetic strategies for various architectures, and providing a better understanding of the parameters governing their self‐assembly. We review here recent developments on the synthesis and self‐assembly of such materials achieved in this field.     

Block Copolymers as a Tool for Nanomaterial Fabrication

In this review the latest developments regarding the use of self‐assembled copolymers for the fabrication of nanomaterials will be presented and their real potential evaluated. Most of the strategies reported so far are herewith classified under two main approaches: a) use of block copolymers as nanostructured materials, either “as they are” or through a selective isolation of one or more component blocks, and b) as templates for the synthesis of metallic or semiconducting nanomaterials. The problems of the orientation and large‐scale order of self‐organizing block copolymer mesophases will be also introduced, due to their importance as a route towards further improvements of the nanofabrication means.     

Preparation of Metallic Line Patterns from Functional Block Copolymers

A simple route for the preparation of nanoscopic metallic line patterns from functional block copolymers (BCPs) containing poly(2‐vinylpyridine) or poly(methyl methacrylate) blocks is demonstrated. The time evolution of the surface morphologies of BCP thin films exposed to solvent vapors is studied to optimize the conditions for generating BCP microdomains oriented parallel or normal to the substrate. BCP templates are prepared by film reconstruction or by removal of one of the copolymer microdomains, depending on the properties of the functional BCPs. Finally, metallic line patterns are prepared by either electrochemical etching or direct metal deposition and lift‐off processes using the BCP templates.     

含氟丙烯酸酯嵌段共聚物乳液的合成及表征

以PEDB(二硫代苯甲酸苯乙基酯)为链转移剂,进行AA(丙烯酸)、BA(丙烯酸丁酯)可逆加成-断裂链转移(RAFT)自由基聚合,得到数均相对分子质量可控、相对分子质量分布窄的聚合物P(AA-BA).以得到的聚合物为大分子RAFT自由基聚合剂,进行舍氟丙烯酸酯的扩链反应,制得稳定的含氟嵌段共聚物P(AA-BA)-b-PTFEA(甲基丙烯酸三氟乙酯)乳液.为了克服RAFT链转移剂在水中迁移慢的缺点,引入了自发相倒置的实验过程,即先进行AA、BA的本体聚合,然后在温和搅拌条件下滴加NaOH溶液,体系发生自发相倒置,产生稳定的亚微型聚合物颗粒,DLS测量乳液颗粒平均大小为4nm.乳液经TEM、DLS观测,粒径为50～60nm,颗粒分布均匀.     

球状嵌段共聚物在方柱中的自组装

采用动态密度泛函理论,对本体为球状相的嵌段共聚物受限于方柱中的相行为进行了模拟研究。考察了在不同受限空间和不同表面场下嵌段共聚物的相转变。许多新颖的不同于本体的有序结构被发现,如浸润相、单排球、双螺旋球、四角排列的柱、方筒层、圆筒层、波浪层等。讨论和比较了相应的结果,这些有趣的相结构对新材料的制备提供了帮助。     

含有POSS的嵌段聚合物的制备及热性能

以单官能团笼状结构倍半硅氧烷(POSS)为引发剂,氯化亚铜/2,2-联吡啶为催化体系,甲苯为溶剂,采用原子转移自由基聚合法(ATRP)制备了大分子引发剂POSS/PMMA和POSS/PMMA-PS嵌段聚合物。通过核磁共振(1H-NMR)、X射线光电子能谱(XPS)和凝胶渗透色谱(GPC)表征了大分子引发剂和嵌段聚合物的结构,实现了POSS在聚合物中的单分散。此外,热重分析(TGA)结果表明,POSS/PMMA和POSS/PMMA-PS嵌段聚合物的分解温度与纯聚甲基丙烯酸甲酯(PMMA)相比分别提高了60℃和151℃。     

Asymmetric Block Copolymers for Supramolecular Templating of Inorganic Nanospace Materials

This review focuses on polymeric micelles consisting of asymmetric block copolymers as designed templates for several inorganic nanospace materials with a wide variety of compositions. The presence of chemically distinct domains of asymmetric triblock and diblock copolymers provide self‐assemblies with more diverse morphological and functional features than those constructed by EO_nPO_mEO_n type symmetric triblock copolymers, thereby affording well‐designed nanospace materials. This strategy can produce unprecedented nanospace materials, which are very difficult to prepare through other conventional organic templating approaches. Here, the recent development on the synthesis of inorganic nanospace materials are mainly focused on, such as hollow spheres, tubes, and porous oxides, using asymmetric triblock copolymers.     

线型与星型聚酰胺6-聚氨酯嵌段共聚物的性能比较

以聚醚多元醇(PPG)、二苯甲烷二异氰酸酯(MDI)以及己内酰胺为单体,在碱性催化剂条件下,通过单体浇铸(MC)工艺制备了线型和星型聚酰胺6/聚氨酯(PA 6-PU)嵌段共聚物。使用差热分析(DSC),扫描电镜分析(SEM)研究了两者的结晶和熔融行为以及微观结构,并进行了比较。研究发现,与线型PA 6-PU嵌段共聚物相比,随着PU组分含量的增加,星型PA 6-PU嵌段共聚物具有较高的熔融温度(Tm)和结晶温度(Tc),并且,两共聚物中的PU与PA的相容性好。比较两者的力学性能,结果显示,同等PU添加量时,星型PA 6-PU嵌段共聚物冲击性能的提高更为明显。