New Strategies for Patterning: Implications for Branched Nacromolecules

技术概述：本项目的目标是探索在亚100纳米长度尺度上的聚合物薄膜图案化的新策略。所提出的方法利用了具有三个特征性质的支链大分子：介观尺寸、明确的形状和共价键的机械张力。这些性质在拴在底物上的支链大分子中变得特别明显，这增强了紧密连接的分支之间的空间排斥力。为了减轻约束引起的应力，支链大分子可以选择进行正交相分离，导致化学性质不同的分子插入，或者破坏连接剂，导致膜中的分子空腔。这些现象的重要意义要求对分支结构在聚合物薄膜微结构中的作用进行基础研究。考虑到薄的意图，建议研究两个互补系统：(i)液体底物上的支链大分子和（ii）与固体底物相连的支链大分子。我们将学习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。实验研究将指导分支结构的设计，并将用于验证薄膜中分子构象和微相分离的理论预测。非技术概述：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观结构，这对微电子、数据存储、光子学和燃料电池具有重要意义。外联计划包括三个关键活动领域：(i)通过高中学生全面参与研究培养未来的科学家；（ii）为大学和高中教室开发分子成像技术；（iii）通过与此类种子项目合作扩大代表性不足群体的参与。该项目还将加强北卡罗来纳大学化学系、卡内基梅隆大学、雅典大学和洛桑联邦理工学院之间的合作。拟议研究计划的跨学科和协作性质为学生准备竞争激烈的全球经济提供了丰富的机会，研究人员必须跨学科和地理距离，以及组织，文化和个人差异一起工作。

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.