CAREER: Complex Hierarchical Self-Assembly Templated by Block Copolymers: Phase Structures, Nano Fabrication and Nano-Electrooptic Properties

分层自组装是纳米技术的重要组成部分，它提供了制造纳米结构集成的少数实用策略之一。层次结构中的结构复杂性是特别重要的，因为它提供了在单一材料中组合不同功能的实用方法。该CAREER发展计划的目标是通过结合二维（2-D）液晶（LC）有序和嵌段共聚物微相分离工艺来实现复杂的分层自组装结构。建议的研究活动包括：(1)设计、合成并系统研究了一系列弯核液晶（BCLC）双嵌段共聚物，以实现包括嵌段共聚物片层（Col-in- lam）、柱状相（Col-in- cyl）和球状相（Col-in- sph）结构在内的新型复杂层次结构。等)使用这些分层自组装的二嵌段共聚物作为模板。(3)探索这些新型层次结构的纳米电光特性。所提出的双嵌段共聚物体系将实现独特的板层厚度控制铁-反铁电性能。电场可调谐纳米结构也将被研究。提出的研究将首次将二维LC有序纳入嵌段共聚物微相分离产生的有序纳米空间。所得的层次结构在1-5 nm和10-100 nm的长度尺度上都具有复杂的性质。从科学的角度来看，该系统提供了一个独特的机会来探索复杂的相几何形状，小相尺寸和大界面对LC以及嵌段共聚物相行为的影响。在这些小的环境中，LC的相稳定性可能被改变，并可能产生新的相结构。从技术的角度来看，这种分层结构可以作为纳米制造应用的模板。不同长度尺度上的良好相关结构也可能为纳米尺度上的新特性转移到更高长度尺度提供解决方案。此外，由于其特殊的结构复杂性，这些分层结构可以作为进一步纳米科学和纳米技术研究的支架，特别是纳米器件制造。结构的复杂性和层次也可能是设计合成材料的关键，这些材料可以模仿优雅的生命系统。拟议职业发展计划的教育部分包括：(1)通过开设一门名为“聚合物和纳米技术”的新课程，满足聚合物纳米科学和纳米技术现代发展的教育需求。(2)让高中学生和教师，特别是代表性不足的人群，参与拟议的聚合物纳米技术研究活动。(3)通过Drexel的Co-op系统，发展PI实验室与行业之间的长期合作。这些拟议的教育活动具有更广泛的影响。首先，将通过一系列指导计划，让高中学生和教师参与研究活动，缩小现有的教育发展水平差距。其次，由于费城地区未被充分代表的群体人口众多，拟议的外展计划将专门针对鼓励未被充分代表的群体参与。第三，拟议的研究成果将通过科学期刊的出版物、与工业界合作所产生的产品发展、以及由于参与研究活动而获得的知识的自然结果——训练有素的中等教育教师——广泛传播。最后，通过与费城周边地区的国家实验室和学区建立合作，拟议的计划将极大地增强研究和教育的基础设施。结合德雷塞尔大学提供的“启动包”，该计划还将使PI能够建立一个最先进的聚合物表征中心，这将使德雷塞尔大学和附近的工业受益。

Hierarchical self-assembly is an essential part of nanotechnology and it offers one of the few practical strategies for making ensembles of nanostructures. Structure complexity in the hierarchical structures is of particular importance since it provides a practical means to combine different functionalities within a single material. The aim of this CAREER development plan is to achieve complex hierarchical self-assembled structures via combining two-dimensional (2-D) liquid crystalline (LC) ordering and block copolymer microphase separation process. The proposed research activities include: (1) Design, synthesize, and systematically investigate a series of bent-core liquid crystalline (BCLC) diblock copolymers in order to achieve novel complex hierarchical structures including LC columnar phase (Col) in block copolymer lamella (Col-in-Lam), Col in cylinder (Col-in-Cyl) and Col in sphere (Col-in-Sph) structures, etc. (2) Fabricate well-defined nano building blocks (such as nano porous plates, rods, spheres, etc.) using these hierarchically self-assembled diblock copolymers as templates. (3) Explore the nano-electrooptic properties of these novel hierarchical structures. Unique lamellar thickness controlled ferro-antiferroelectric properties will be realized in the proposed diblock copolymer system. Electric field tunable nanostructures will also be investigated. The proposed research will, for the first time, incorporate 2-D LC ordering into the ordered nanospace created by block copolymer microphase separation. The resulting hierarchical structures possess complex natures at both 1-5 nm and 10-100 nm length scales. From a scientific point of view, this system provides a unique opportunity to explore the complex phase geometry, small phase size and large interface effects on LC as well as block copolymer phase behaviors. LC phase stability might be altered in these small environments and novel phase structures might be generated. From the technological point of view, the hierarchical structures could be used as templates for nano fabrication applications. Well-correlated structures at different length scales might also provide a solution for the transfer of the novel properties at the nanoscale into a higher length scale. Furthermore, these hierarchical structures can serve as a scaffold for further nanoscience and nanotechnology research, particularly for nano device manufacturing due to their specific structure complexity. The structural complexity and hierarchies might also hold the key to designing synthetic materials that can mimic the elegant living systems. The educational component of the proposed CAREER development plan includes (1) Address the needs for the education of modern developments in polymer nanoscience and nanotechnology by developing a new course entitled Polymers and Nanotechnology. (2) Involve high school students and teachers, particularly under-represented populations, in the proposed polymer nanotechnology research activities. (3) Develop long-term collaborations between the PI's laboratory and industry through Drexel's Co-op system. These proposed education activities impose a broader impact. First, the proposed plan will help to bridge the existing gap between levels of educational developments by involving high school students and teachers in research activities through a number of mentorship programs. Secondly, due to the high population of under-represented groups in the Philadelphia region, the proposed out-reach program will be specifically geared towards encouraging the participation of under-represented populations. Thirdly, the proposed research results will be widely disseminated through publications in scientific journals, product development resulting from collaborations with industry and, as a natural outgrowth of gained knowledge resulting from involvement in research activities, more highly trained secondary education teachers. Lastly, through the establishment of collaborations with national laboratories and school districts in the surrounding Philadelphia region, the proposed plan will dramatically enhance the infrastructure for research and education. Combined with the "start-up package" supplied by Drexel University, the proposed plan will also enable the PI to establish a state-of-the-art polymer characterization center that will benefit both Drexel University and nearby industry.