Functional Assemblies of Block Copolymers and Polymer-Stabilized Nanoparticles

光子学、信号处理、生物成像和传感领域对先进材料的需求刺激了纳米级调谐材料特性的研究领域的发展。嵌段共聚物是一种具有显著自组织倾向的合成分子，具有各种形态的复杂胶体结构，包括胶束和囊泡。金属和半导体纳米粒子由于其独特的光学和电子特性，可以作为尺寸的函数进行调节，因此作为各种纳米结构材料的基石，它们是令人兴奋的候选者。对于器件和先进材料的应用，在聚合物和纳米复合材料中控制纳米颗粒和嵌段共聚物的组装是一个关键的挑战。我的研究项目侧重于开发嵌段共聚物、金属和半导体纳米颗粒在聚合物系统中的分层组织的新方法，包括薄膜和胶体。我们的纳米颗粒组装策略利用由纳米颗粒封装在稳定的聚合物胶束内的混合构建块。我们利用每个纳米颗粒周围的聚合物刷层来控制各种自发结构形成过程，从而在多个长度尺度上控制纳米颗粒的自组装。这些自下而上的过程也可以耦合到自上而下的方法，如微接触印刷和微流体，以行使对尺寸，结构和复杂性的外部处理。我们还试图了解聚合-纳米粒子组合的集体光学性质，以及这些性质与不同长度尺度上的结构之间的关系。通过结构控制和聚合物-纳米颗粒材料结构-性能关系测定的结合发展，我们将建立各种应用的调谐功能方法，包括光子电路元件，化学和温度传感器，以及多功能药物递送载体。

The need for advanced materials for photonics, signal processing, biological imaging, and sensing has spurred a growing field of research into tuning material properties at the nano-scale. Block copolymers are synthetic molecules with a remarkable tendency to self-organize into complex colloidal structures of various morphologies, including micelles and vesicles. Metallic and semiconductor nanoparticles are exciting candidates as building blocks for a diverse range of nanostructured materials, due to unique optical and electronic properties that can be tuned as a function of size. For applications in devices and advanced materials, controlling the assembly of nanoparticles and block copolymers in polymeric and nanocomposite materials is a critical challenge. My research program focuses on developing new methods for hierarchical organization of block copolymers and metal and semiconductor nanoparticles in polymer systems, both in thin films and colloids. Our strategy for nanoparticle assembly utilizes hybrid building blocks consisting of nanoparticles encapsulated inside stable polymeric micelles. We use the polymeric brush layer surrounding each nanoparticle to harness various spontaneous structure-forming processes, resulting in controlled nanoparticle self-assembly on multiple length scales. These bottom-up processes can also be coupled to top-down methodologies such as microcontact printing and microfluidics, in order to exercise external handles on size, structure, and complexity. We also seek to understand the collective optical properties of the resulting polymer-nanoparticle assemblies, and how these properties relate to structure on various length scales. Through the combined development of structure control and determination of structure-property relations in polymer-nanoparticle materials, we will establish methodologies for tuning function toward various applications, including photonic circuit elements, chemical and temperature sensors, and multifunctional drug-delivery vehicles.