Ordering and Helical Structures of Nanoparticles in Block Copolymers

提出的项目的目的是控制由纳米颗粒（NP）在嵌段共聚物（BCP）约束下形成的复杂结构，这是令人惊讶的。目的是将纳米颗粒驱动到其中一个BCP域内，并利用BCP模板提供的约束效应，诱导纳米颗粒自组装形成定义良好的结构。由光学活性纳米粒子（如银或金）组成的螺旋结构引起了特别的兴趣。将纳米粒子与聚合物层进行合成和功能化，然后与嵌段共聚物混合，得到具有区域选择性NP排列的NP/BCP复合材料。我们最近的实验结果清楚地表明，在BCP约束下，纳米颗粒可以自组装形成螺旋结构。然而，关于决定和影响螺旋形成的可能机制和参数的信息有限。BCP结构域尺寸（主体）与纳米颗粒尺寸（客体）之比、链长、接枝密度、溶剂的选择性等因素都将对聚合物的反应产生重要影响。这些参数将系统地变化，并研究它们对BCP约束下NP螺旋结构形成的影响。在选择性溶剂的帮助下，NP/BCP复合材料将转化为孤立的纳米物体（即纳米纤维），其中纳米颗粒组装成螺旋结构。我们期望具有螺旋纳米粒子组件的NP/BCP复合材料可能显示出特定的光学性质，例如光学二色性或光偏振性。计算机模拟将用于指导这种多维参数空间中的结构形成，并提供对嵌段共聚物约束下纳米颗粒自组装的理解。这里，强选择性溶剂和共聚物的体相都将被考虑。实验与模拟相结合有助于了解纳米颗粒形成的细节。我们期望这个项目能够导致具有光学特性的新功能材料的发展，这些材料可以通过环境和化学来调节。

The aim of the proposed project is the control of complex structures formed by nanoparticles (NP) under block copolymer (BCP) confinement which surprisingly are observed. The purpose is to drive the nanoparticles inside of one of the BCP domains and, by exploiting confinement effects provided by BCP template, induce the nanoparticle self-assembly to form well-defined structures. Helical structures composed of optically active nanoparticles, such as silver or gold, are of particular interest. The nanoparticles will be synthesized and functionalized with polymer layer and then mixed with block copolymers to obtain NP/BCP composites with domain-selective NP arrangement. Our recent experimental results clearly demonstrate that under BCP confinement nanoparticles can self-assemble to form helical structures. There is limited information, however, about the possible mechanisms and parameters which determine and influence the helix formation. The ratio between the BCP domain size (host) and nanoparticle size (guest), the chain length and grafting density of particle-tethered polymer, the selectivity of solvent would play an important role. These parameters will be systematically varied and their impact on formation of NP helical structures under BCP confinement will be studied. With the aid of selective solvents NP/BCP composites will be converted into isolated nanoobjects, (i.e. nanofibers) bearing the nanoparticles assembled into helical structures. We expect that NP/BCP composites with helical nanoparticles assemblies may display specific optical properties, such as optical dichroic or light polarisation properties. Computer simulations will be used to guide structure formation in this multi-dimensional parameter space and provide an understanding of the self-assembly of nanoparticles under the block copolymer confinement. Here, both strongly selective solvents and the bulk phase of copolymers will be considered. The combination of experiment and simulation will help to understand details of formation of nanoparticle. We expect that this project can lead to the development of new functional materials with optical properties which can be tuned by the environment and by chemistry.