Theoretical Investigations of Structure and Properties in Complex Materials

自组装是无序系统的组成部分相互作用形成有组织的模式或新兴结构的过程。在纳米技术中，通过设计元件自组装并实现所需的复合物或器件，可以有效地实现器件向分子尺度的小型化。在有机电介质和有机半导体的栅极导体上逐层组装可以在纳米尺度上制造工作晶体管阵列，在制造更小、更强大的计算机芯片、电荷存储和机器人应用方面具有潜在的应用前景。嵌段共聚物可以自组装成具有设计性能的功能材料。自组装程序被预测为太阳能电池制造和体内诊断和治疗的可行方法。******尽管最近取得了重大进展，但目前对自组装过程的理解仍然主要是经验和零碎的。理论研究可以为了解众多相关因素如何相互作用和影响自组装过程提供有价值的见解。然而，在考虑整个系统时，考虑局部相互作用的方法仍然具有挑战性。总的来说，目前的理论研究要么解释实验数据，比如基于经验初始结构的模拟，要么忽略局部相互作用，以粗粒度的方式处理整个系统。我们感兴趣的自组装材料问题是层次结构的结果，从长远来看，我们的研究计划旨在开发多尺度方法来研究它们。这包括一系列步骤：发展对局部分子水平行为的理解，然后将这种理解作为一个整体用于宏观系统的处理，最后为局部计算提供关于整体的反馈。在短期内，我们将关注两个具有重要实际意义的现象：(a)固体表面的自组装，重点是复杂的相互作用，纳米结构表面，势能表面上竞争最小值的有效采样，以及纳米复合材料组装。这些现象在纳米级器件、生物传感器、功能材料的制造和对映体药物的分离上有直接的应用。(b)自组装光学和介电材料，着眼于与电荷存储、光伏和可调谐介电响应有关的应用。

Self--assembly is the process by which the components of a disordered system interact to form an organized pattern or emerging structure. In nanotechnology, miniaturization of devices towards the molecular scale can be efficiently achieved by designing the components to self--assemble and realize the desired complex or device. Working transistor arrays can be fabricated at the nanoscale using layer-by--layer assembly onto the gate conductor of an organic dielectric and an organic semiconductor, with potential application in the fabrication of smaller, more powerful computer chips, for charge storage and robotics applications. Block copolymers can be built to self--assemble into functional materials with designed properties. Self--assembly procedures are forecast as viable methods for fabrication of solar cells, and for in--vivo diagnosis and treatment.******Despite significant recent advances, the current understanding of the self--assembly process is still mainly empirical and fragmentary. Theoretical research can provide valuable insight into how a multitude of relevant factors interact and impact the self-assembly process. However, methodologies to account for local interactions when considering the system as a whole are still challenging to develop. By and large, current theoretical investigations either interpret experimental data, such as simulations based on empirical initial structures, or neglect local interactions and treat the entire system in a coarse--grained fashion. The self--assembled materials problems we are interested in are the result of a hierarchy of scales, and our research program aims, in the long run, to develop multi--scale approaches to investigate them. This involves a succession of steps: Developing an understanding of the local, molecular level behaviour, then using this understanding in the treatment of the macroscopic system as a whole, and finally providing feedback about the whole to the local calculations. In the short term, we will focus on two phenomena of significant practical importance: (a) Self--assembly at the solid surface, with an emphasis on complex interactions, nano--structured surfaces, the efficient sampling of competing minima on the potential energy surface, and nanocomposite assembly. These phenomena have immediate applications for nanoscale devices, biosensors, and the fabrication of functional materials and separation of enantiomeric drugs. (b) Self--assembled optical and dielectric materials, with an eye towards applications related to charge storage, photovoltaics and tunable dielectric response.