New Strategies for Patterning: Implications for Branched Nacromolecules

技术概述：该项目的目标是探索在100 nm以下长度尺度上形成聚合物薄膜图案化的新策略。该方法利用支化大分子具有三个特征性质：介观尺寸、明确的形状和共价键的机械张力。这些性质在捆绑在底物上的支化大分子中变得特别明显，这增强了紧密连接的支链之间的空间斥力。为了减轻限制引起的应力，支化的大分子可以选择经历导致化学上不同分子插入的正交相分离，或者破坏连接物导致膜中的分子空洞。这些现象的重大意义要求进行基础研究，以阐明支化结构在聚合物薄膜微结构中的作用。有鉴于此，建议研究两个互补的体系：(I)液体基质上的支化大分子和(Ii)与固体基质相连的支化大分子。其中一个将研究分子插层的热力学和动力学，以了解图案形成的机制和长度尺度。实验研究将指导支化结构的设计，并将用于验证分子构象和薄膜微相分离的理论预测。非技术总结：该项目将产生新的材料和物理工具，用于在分子长度尺度上控制聚合物薄膜的微结构，这对微电子、数据存储、光子学和燃料电池具有重要意义。推广计划包括三个主要活动领域：(I)通过高中生全面参与研究培养未来的科学家；(Ii)为大学和高中课堂开发分子成像技术；(Iii)通过与Suc-SEED项目合作，扩大代表不足群体的参与。该项目还将加强北卡罗来纳大学、卡内基梅隆大学、雅典大学和洛桑联邦理工学院化学系之间的合作。拟议的研究计划的跨学科和协作性质为学生为竞争激烈的全球经济做好准备提供了丰富的机会，在全球经济中，研究人员必须跨越学科和地理距离以及组织、文化和个人差异进行合作。

TECHNICAL SUMMARY: The goal of this project is to explore new strategies in patterning of thin polymer film on sub-100 nm length scales. The proposed approach takes advantage of branched macromolecules that possess three characteristic properties: mesoscopic size, well-defined shape, and mechanical tension in their covalent bonds. These properties become particularly evident in branched macromolecules tethered to a substrate which enhances steric repulsion between the densely connected branches. To alleviate the confinement-induced stress, branched macromolecules may opt to either undergo orthogonal phase separation leading to intercalation of chemically different molecules or break the linker leading to molecular cavities in the film. The significant implications of these phenomena call for fundamental studies to shed light on the role of the branched architecture in micro-structuring of thin polymer films. With thin intention in mind, it is proposed to investigate two complementary systems: (i) branched macromolecules on liquid substrate and (ii) and branched macromolecules tethered to a solid substrate. One will study thermodynamics and kinetics of molecular intercalation to understand the mechanisms and the length scale of the pattern formation. The experimental studies will guide the design of branched architectures and will be used to verify the theoretical predictions for molecular conformation and microphase separation in thin films. NON-TECHNICAL SUMMARY:This project will generate new materials and physical tools for controlling microstructure of thin polymer films on molecular length scales, which carry vital implications for microelectronics, data storage, photonics, and fuel cells. The outreach plan includes three key areas of activity: (i) nurturing prospective scientists through comprehensive participation of high-school students in research, (ii) the development of molecular imaging techniques for university and high-school classrooms, (iii) broadening participation of underrepresented groups through collaboration with the suc-SEED Project. The project will also strengthen collaboration between the chemistry departments at UNC, Carnegie Mellon University, the University of Athens, and Ecole Polytechnique Federale de Lausanne. The interdisciplinary and collaborative nature of the proposed research program provides rich opportunities for preparation of students for the competitive global economy where researchers must work together across disciplines and geographic distances, as well as organizational, cultural, and personal differences.